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<p>The synthesis of a dimeric boryloxorhodium complex having the Rh–O–Bpin scaffold from the reaction of [(cod)Rh(OMe)]2 or [(cod)Rh(OH)]2 with an arylboronate has been achieved. The obtained dirhodium complex is converted...</p>

DOI： 10.1039/d1dt00440a

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DOI： 10.1021/acs.orglett.0c02781

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DOI： 10.1021/acs.orglett.0c02671

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

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We report the design, synthesis, and physicochemical properties of an array of phenanthro[2,1-b:7,8-b’]dithiophene (PDT-2) derivatives by introducing five types of alkyl (CnH2n+1; n = 8, 10, 12, 13, and 14) or two types of decylthienyl groups at 2,7-positions of the PDT-2 core. Systematic investigation revealed that the alkyl length and the type of side chains have a great effect on the physicochemical properties. For alkylated PDT-2, the solubility was gradually decreased as the chain length was increased. For instance, C8-PDT-2 exhibited the highest solubility (5.0 g/L) in chloroform. Additionally, substitution with 5-decylthienyl groups showed poor solubility in both chloroform and toluene, whereas PDT-2 with 4-decylthienyl groups resulted in higher solubility. Furthermore, UV-vis absorption of PDT-2 derivatives substituted by decylthienyl groups showed a redshift, indicating the extension of their π-conjugation length. This work reveals that modification of the conjugated core by alkyl or decylthienyl side chains may be an efficient strategy by which to change the physicochemical properties, which might lead to the development of high-performance organic semiconductors.

DOI： 10.3390/molecules25173842

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DOI： 10.1021/acs.orglett.0c02215

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>Polymer libraries were synthesized in good yields from half-esters efficiently prepared by the selective monohydrolysis of symmetric diesters we reported.</p>

DOI： 10.1039/d0ob01252a

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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp(2))-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.

DOI： 10.1021/acs.joc.0c00640

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To investigate organic field-effect transistor (OFET) properties, a new thienoacene-type molecule, 4,14-dihexyldinaphtho[2,3-d:2’,3’-d’]anthra[1,2-b:5,6-b’]dithiophene (C6-DNADT), consisting of π-conjugated nine aromatic rings and two hexyl chains along the longitudinal molecular axis has been successfully synthesized by sequential reactions, including Negishi coupling, epoxidation, and cycloaromatization. The fabricated OFET using thin films of C6-DNADT exhibited p-channel FET properties with field-effect mobilities (µ) of up to 2.6 × 10−2 cm2 V−1 s−1, which is ca. three times lower than that of the parent DNADT molecule (8.5 × 10−2 cm2 V−1 s−1). Although this result implies that the installation of relatively short alkyl chains into the DNADT core is not suitable for transistor application, the origins for the FET performance obtained in this work is fully discussed, based on theoretical calculations and solid-state structure of C6-DNADT by grazing incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) analyses. The results obtained in this study disclose the effect of alkyl chains introduced onto the molecule on transistor characteristics.

DOI： 10.3390/ijms21072447

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Carboxylic acid derivatives containing acyl halides, anhydrides, esters, amides and acyl nitriles are highly appealing electrophiles in transition-metal-catalyzed carbon-carbon bond-forming reactions due to their ready availability and low cost, which can provide divergent transformations of carboxylic acids into other value-added products. In this Minireview, we focus on the recent advances of decarbonylative transformations of carboxylic acid derivatives in carbon-carbon bond formations using Ni or Pd catalysts. A series of reaction types, product classifications and reaction pathways are presented herein, which show the advantageous features of carboxylic acid derivatives as alternative to aryl or alkyl halides in terms of reactivity and compatibility. The well-accepted mechanism of nickel- or palladium-catalyzed decarbonylative transformations involves initial oxidative addition of carboxylic acid derivatives, followed by decarbonylation or transmetalation (or insertion), and reductive elimination to generate the products, thereby regenerating the catalysts.

DOI： 10.1002/asia.202000117

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DOI： 10.1021/acs.joc.9b02392

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Ni-catalyzed decarbonylative cyanation of acyl chlorides with trimethylsilyl cyanide has been achieved. This transformation is applicable to the synthesis of an array of nitrile compounds bearing a wide range of functional groups under neutral conditions. The step-by-step experimental studies revealed that the reaction sequences of the present catalytic reaction are oxidative addition, transmetalation, decarbonylation, and reductive elimination.

DOI： 10.1021/acs.orglett.9b02398

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Chemical Society of Japan  

DOI： 10.1246/cl.190304

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Ni/Cu-cocatalyzed decarbonylative silylation of acyl fluorides with silylboranes has been developed to afford various arylsilanes with high efficiency and good functional-group compatibility via carbon-fluorine bond cleavage and carbon-silicon bond formation. Such transformation can not only extend the functionalization type of acyl fluorides but complement the synthetic route for arylsilanes.

DOI： 10.1039/c9cc05325e

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We describe the (triphenylphosphine (PPh3)-assisted methoxylation of acyl fluorides with cyclopentyl methyl ether (CPME) accelerated by tetrabutylammonium difluorotriphenysilicate (TBAT) via regiospecific C–OMe bond cleavage. Easily available CPME is utilized not only as the solvent, but a methoxylating agent in this transformation. The present method is featured by C–O and C–F bond cleavage under metal-free conditions, good functional-group tolerance, and wide substrate scope. Mechanistic studies revealed that the radical process was not involved.

DOI： 10.3390/catal9070574

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© 2019 The Chemical Society of Japan. Bis[1]benzothieno[5,4-d:5¤,4¤-d¤]benzo[1,2-b:4,5-b¤]dithiophene (BBTBDT-2) and its phenyl-substituted derivative were successfully synthesized and characterized. From DFT calculations, highest occupied molecular orbitals (HOMOs) of both compounds are well delocalized and large orbital coefficients exist on sulfur atoms. Single-crystal X-ray analysis revealed that BBTBDT-2 derivatives formed herringbone structures in the solid state. In particular, BBTBDT-2 formed a layer-by-layer structure with effective 2D charge-carrier transporting capability. The fabricated OFETs based on BBTBDT-2 gave mobility up to 0.49 cm2 V11 s11 in the vacuum-deposited thin films, which is the highest value among BBTBDT derivatives including our previously reported syn-counterparts. We have also clarified a detailed structureproperty relationship of sulfur positions and phenyl substituents as indicated by theoretical calculation, GIWAXS, and AFM analyses.

DOI： 10.1246/bcsj.20180358

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DOI： 10.1021/acs.orglett.9b01059

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Nickel-catalyzed decarbonylative stannylation of acyl fluorides under ligand-free conditions was disclosed. A variety of aromatic acyl fluorides are capable of reacting with silylstannanes in the presence of cesium fluoride. A one-pot decarbonylative stannylation/Migita-Kosugi-Stille reaction of benzoyl fluoride, giving rise to the direct formation of the corresponding cross-coupled products, further demonstrated the synthetic utility of the present method. This newly developed methodology with a good functional-group compatibility via C–F bond cleavage and C–Sn bond formation under nickel catalysis opens a new area for the functionalization of acyl fluorides in terms of carbon-heteroatom bond formation.

DOI： 10.3390/molecules24091671

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DOI： 10.1246/cl.180937

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DOI： 10.1021/acs.joc.8b02557

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<p>A new class of an acceptor unit, vinylene-bridged 5,6-difluorobenzothiadiazole <bold>FBTzE</bold>, and three <bold>FBTzE</bold>-containing copolymers has been synthesized and characterized.</p>

DOI： 10.1039/c8tc05764h

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The first Ni(cod)(2)/PPh3 catalyst system has been established for decarbonylative borylation of aroyl fluorides with bis(pinacolato)diboron. A wide range of functional groups in the substrates were well tolerated. The ease of access of the starting aroyl fluorides indicates that these results might become an alternative to the existing decarbonylation events.

DOI： 10.1039/c8cc08504h

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/pola.29248

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/pola.29248

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Herein, nickel-catalyzed decarbonylative C-F bond alkylation of aroyl fluorides with organoboron reagents is reported. Aroyl fluorides are more chemically stable than the corresponding aroyl chlorides and can be readily synthesized from the corresponding carboxylic acids. The fluoronickel intermediate formed via oxidative addition interacts with Lewis-acidic trialkylboranes, and the subsequent decarbonylative alkylation proceeds. This new synthetic methodology allows 1,2-bifunctionalization of aromatic carboxylic acids via palladium-catalyzed ortho-C-H arylation. addition, an unprecedented 1,4-nickel migration on ortho-atylated aroyl fluorides was observed As a demonstration of the synthetic utility of the present reaction, the sequential 1-alkyl-2-arylation of 3-hydroxy-2-naphthoic acid was accomplished via chemoselective alkylation at a fluorocarbonyl moiety and the subsequent C-O bond arylation at an acetoxy group.

DOI： 10.1021/acsomega.8b02155

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DOI： 10.1246/cl.180644

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nature Publishing Group  

The incorporation of a highly extended π-electron system into a polymer backbone is an effective strategy to develop high-performance donor–acceptor (D–A) polymers suitable for organic electronics because this strategy can facilitate a dense π-π stacking structure, leading to efficient carrier transport. With this in mind, we developed phenanthro[1,2-b:8,7-b′]dithiophene (PDT) because this new phenacene-type molecule has a highly crystalline nature, deep HOMO level, and high hole mobility, which are characteristics known to be suitable for a donor unit in high-performance D–A polymers. In this focus review, we report recent progress in PDT-containing D-A polymers combined with various strong acceptor units. Incorporation of PDT into a polymer backbone results in deep HOMO energy levels of −5.4~−5.5 eV, strong aggregation, and a dense packing structure with a short π-stacking distance of 3.5~3.6 Å. PDT-based polymers with appropriate alkyl side chains exhibit high hole mobilities of up to 0.18 cm2 V−1 s−1 in organic field-effect transistor (OFET) devices due to their tendency to form highly ordered edge-on structures. Furthermore, we can adjust their level of molecular orientation from edge-on to face-on by increasing their molecular weight, leading to a high power conversion efficiency of over 6% in polymer solar cell (PSC) applications. These results demonstrate that PDT is a good candidate as a high-performance building block in D-A polymers.

DOI： 10.1038/s41428-018-0072-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Synthesis, characterization, and solar cell application of three 4,7-dialkylated phenanthro[1,2-b:8,7-b′]dithiophene (PDT)-difluorobenzothiadiazole (DFBT copolymers (P1-P3) with different linear alkyl side chains to improve solubility, molecular weight, and molecular orientation are described. The utilization of Ir-catalyzed direct borylation and sequential functionalization can selectively afford the target 4,7-dialkylated PDT as the monomers. Migita-Kosugi-Stille coupling in the presence of CuI can accelerate polymerization to afford high-molecular-weight polymers along with their improved solubility. The effect of alkyl substitution at the 4,7-positions on the electronic structure of PDT-DFBT copolymers is negligible. By installation of additional alkyl chains at the 4,7-positions of PDT, the synthesized polymers P1-P3 have lower intermolecular interaction than that of nonalkylated P0, but they still maintained aggregation behavior in solution. In addition, they formed a favorable face-on orientation with a short π-stacking distance of 3.6 Å, which can enhance their carrier transport ability, resulting in high Jsc and FF. As a result, their fabricated solar cells reached a PCE exceeding 6%, which are about 1.7-fold higher than that of P0. Comparison of alkyl side chain length at the 4,7-positions of PDT revealed that all polymers formed a predominantly face-on orientation and have a similar face-on ratio in blended films, but their crystallinity was decreased as the carbon chains at the 4,7-positions of PDT became shorter. On the other hand, the polymers with short alkyl side chains tended to have low surface roughness and small domain size of active layers, which is an ideal phase separation structure for high-performance PSCs. From these results, it could be seen that the polymers have a trade-off relationship between their domain size and crystallinity, but the impact of alkyl side chain length on their photovoltaic properties is rather small. Thus, the construction of face-on orientation is highly important to achieve a high PCE. Among three polymers, the P3/PC61BM-based solar cell with an optimal nanoscale phase separation structure with bicontinuous domain showed the highest PCE of up to 6.6%.

DOI： 10.1021/acs.macromol.7b02734

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This paper reports the synthesis of D-A polymers containing 1,2-dithienylethene (DTE) units via palladium-catalyzed direct arylation polymerization (DArP). The reaction of dibromoisoindigo (1-Br) and DTE (2-H), in the presence of Pd2(dba)3·CHCl3 (0.5 mol%), P(2-MeOC6H4)3 (L1) (2 mol%), pivalic acid (1 equiv) as catalyst precursors, and Cs2CO3 (3 equiv) as a base affords poly(1-alt-2) with a high molecular weight (Mn up to 44,900). Although, it has been known that monomers, with plural C–H bonds, tend to form insoluble materials via direct arylation at undesirable C–H positions
the reaction of 1-Br and 2-H cleanly proceeds without insolubilization. The resulting polymer has a well-controlled structure and exhibits good charge transfer characteristics in an organic field-effect transistor (OFET), compared to the polymer produced by Migita–Kosugi–Stille cross-coupling polymerization. The DArP product displays an ideal linear relationship in the current–voltage curve, whereas the Migita–Kosugi–Stille product shows a VG-dependent change in the charge mobility.

DOI： 10.3390/molecules23040981

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Language：Japanese   Publisher：Society of Synthetic Organic Chemistry  

Over the last two decades, transition-metal-catalyzed chelate-assisted direct functionalization of aryl C-H bonds has been well developed. These methodologies realized the efficient carbon -carbon, carbon-oxygen, carbon-nitrogen, and carbon-halogen bond formations. However, the related catalytic direct thiolation and selenation have yet to be disclosed despite the utilities of organosulfur and organoselenium compounds as building blocks in bioactive molecules and functional organic materials. Very recently, several research groups including our group have developed chelate-assisted intermolecular direct thiolation and selenation by using various transition metal catalysts, such as palladium, rhodium, nickel, copper, ruthenium, and cobalt. This article describes our recent studies on chelate-assisted catalytic direct thiolation and selenation of aryl C-H bonds. The reactions with thiols, disulfides, selenols, diselenides, and elemental selenium proceeded well in the presence of palladium or nickel catalyst to provide a variety of organochalcogen compounds. In addition, an appropriate choice of the directing group can be made to control the reaction sites.

DOI： 10.5059/yukigoseikyokaishi.76.11

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A palladium-catalyzed benzannulation with o-bromobenzyl alcohols enabled the facile construction of phenanthrene skeletons via the sequential multiple carbon-carbon bond formations. A variety of multisubstituted phenan-threnes were synthesized by the reaction of (Z)-beta-halostyrenes with o-bromobenzyl alcohols as well as by the three-component coupling of alkynes, aryl bromides, and o-bromobenzyl alcohols. The electron-deficient phosphine ligand played an important role to control the sequential oxidative addition of two different organic halides employed, which realized the selective formation of the desired phenanthrenes in good yields. This synthetic protocol was also applicable to the synthesis of the highly fused polycyclic aromatic hydrocarbons such as tetraphenes.

DOI： 10.1021/acs.joc.7b00848

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Phenanthro[1,2-b:8,7-b']dithiophene (PDT)isoindigo (IID)-based polymers 12OD (L) and 12OD (H) with a different molecular weight were synthesized and characterized. By using further purified PDT and IID monomers, the high-molecular-weight polymer 12OD (H) with number-average molecular weight (M-n) over 50 kDa was obtained. Both 12OD (L) and 12OD (H) polymers have the same energy gap and highest occupied molecular orbital (HOMO) energy levels, indicating that the influence of molecular weight on their electronic structure is negligible, although 12OD (H) has stronger aggregation behavior than 12OD (L). 12OD (H)-based solar cells fabricated by using optimal solvent and additives showed an increased short-circuit current density (J(sc)) with same open-circuit voltage (V-oc) and fill factor (FF), resulting in a significantly improved power conversion efficiency (PCE) of up to 6.1%, which is approximately 70% higher than that of the 12OD (L)-based cell (3.5%). This result is due to the different molecular orientation caused by the higher molecular weight. Grazing incidence wide-angle X-ray scattering (GIWAXS) analyses revealed that the blended film of 12OD (H)/[6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) formed a face-on orientation with a long-range ordered structure, while a low crystalline edge-on structure was observed in the blended film of 12OD (L)/PC61BM. Such high crystalline and favorable molecular orientation could promote light harvesting efficiency and hole transporting ability, resulting in high J(sc) and thus an excellent PCE. From the detailed GIWAXS analysis, the orientation change of 12OD (H) was induced by the addition of PC61BM. This result suggests that the strong aggregation ability of 12OD (H) can drive crystallization and favors active interaction with PC61BM to form a face-on orientation. In this study, the increase in molecular weight can improve not only the thin-film structure such as crystallinity and phase separation structure but also the molecular orientation in the PDT-based polymer system.

DOI： 10.1021/acs.macromol.7b00778

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nickel-catalyzed direct selenation of benzamides bearing an 8-quinolyl auxiliary with elemental selenium provides benzoisoselenazolones in good yield via carbon selenium and nitrogen-selenium bond formation under aerobic conditions. In addition to aryl C-H bonds, the method can also be applied to alkenyl C-H bonds, constructing an isoselenazolone skeleton. Simple mechanistic analysis shows that the reaction proceeds through a rate-determining C-H bond cleavage. The obtained benzoisoselenazolones are transformed into various organoselenium compounds and utilized as the catalyst for bromolactonization of alkenoic acids.

DOI： 10.1021/acs.orglett.7b00116

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Efficient synthesis and characterization of several piceno[4,3-b:9,10-b′]dithiophene (PiDT) derivatives by Negishi coupling, epoxidation, and Lewis acid-catalyzed cycloaromatization sequences and their potential utility in organic field-effect transistors (OFETs) have been reported. PiDT derivatives, with extended π-electron systems, showed high air stability due to their deep highest occupied molecular orbital energy levels (around -5.6 eV). OFET devices based on 2,11-dioctylated PiDT (C8-PiDT) showed excellent hole mobility, as high as 2.36 cm2 V-1 s-1. Their structure-property relationships were investigated by X-ray diffraction and atomic force microscopy.

DOI： 10.1021/acsomega.7b00015

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We report the straightforward synthetic method and characterization of bis[1]benzothieno[2,3-d:2',3'-d']anthra[1,2-b:5,6-b']dithiophene (BBTADT) having nine aromatic rings fused without solubilizing groups. The highest mobility of fabricated OFETs utilizing BBTADT exhibited 2.7 x 10(-2) cm(2) V-1 s(-1) in polycrystalline films formed by vapor deposition, depending on the annealing temperatures of a substrate.

DOI： 10.1039/c6ra27455b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

A new phenacene-type molecule with five fused aromatic rings was synthesized: 2,7-didodecylphenanthro[2,1-b: 7,8-b'] dithiophene ((C12H25)(2)-i-PDT), with two terminal thiophene rings. Field-effect transistors (FETs) using thin films of this molecule were fabricated using various gate dielectrics, showing p-channel normally-off FET properties with field-effect mobilities (mu) greater than 1cm(2) V-1 s(-1). The highest mu value in the thin-film FETs fabricated in this study was 5.4 cm(2) V-1 s(-1), when a 150 nm-thick ZrO2 gate dielectric was used. This implies that (C12H25)(2)-i-PDT is very suitable for use in a transistor. Its good FET performance is fully discussed, based on electronic/topological properties and theoretical calculations.

DOI： 10.1038/srep38535

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Language：Japanese   Publisher：SOC SYNTHETIC ORGANIC CHEM JPN  

In this paper, the efficient methodology for the synthesis of multi-substituted olefins by using zirconocene complexes is described. The key step is regioselective formation of zirconacyclopentenes from alkynylboron and alkynylsilane compounds. The subsequent Negishi and Suzuki-Miyaura coupling reactions of C-B and C-Zr bonds give rise to multi-substituted olefins. The developed reaction can be applicable to the synthesis of various functional molecules, for example, an anti-cancer agent. In addition, the mechanism for a regioselective formation of zirconacyclopentenes is analyzed by reactions of alkynylboronates and a zirconocene (II) complex. As a result, it is disclosed that an electrostatic interaction effected the regioselective formation of zirconacyclopentenes. The synthesis of various unprecedented tri- and tetra-alkylated olefins using beta-hydrogen containing alkyl electrophiles and alkylzinc reagents as coupling partners in regio- and stereocontrolled manners is also described.

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Multisubstituted olefins are fundamental motifs in organic compounds. In this account, we describe the synthesis of organic molecules bearing an olefinic moiety by the transition-metal-catalyzed regio- and stereoselective addition of a variety of interelement compounds to alkynes. Regio- and stereoselective silaboration, diborylation, and chlorothiolation have been achieved by using the transition-metal catalysts. The subsequent cross-coupling reactions of the boron-containing alkenes to install various aryl groups afforded the corresponding tri- and tetraarylated olefins. This account describes our research on the highly regio- and stereoselective synthesis of multifunctionalized olefins such as tetraarylethenes with four different aryl groups.

DOI： 10.1002/tcr.201600017

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Palladium-catalyzed carbothiolation of terminal alkynes with azolyl sulfides affords various 2-(azolyl)alkenyl sulfides with perfect regio- and stereoselectivities. The present addition reaction proceeded through a direct cleavage of carbon-sulfur bonds in azolyl sulfides. The resulting adducts that are useful intermediates in organic synthesis are further transformed to multisubstituted olefins containing azolyl moieties.

DOI： 10.1021/acs.orglett.6b00503

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New PDT-based polymers were combined with two types of benzothiadiazole (BT) derivatives to improve their crystallinity and solar cell performance. These polymers show several advantages, including strong intermolecular interactions, deep HOMO energy levels, and a dense packing structure with a short pi-pi stacking distance of 3.5-3.6 angstrom. Combinations of PDT and BT units in polymers formed highly crystalline thin films with a long-range order, even in films blended with a fullerene derivative. This suggests that the introduction of optimal acceptor units may increase the regularity of the polymers, leading to effective pi-pi overlaps between the polymer backbones. However, although the present polymers also formed an appropriate phase separation structure in blended films, in fabricated solar cell devices they yielded low power conversion efficiencies (PCEs) not exceeding 3.8%. GI-WAXS analysis revealed that both polymers were present in a predominantly edge-on orientation. This unsuitable orientation for PSCs prevented efficient carrier transport and reduced charge collection efficiency, resulting in low J(sc) and thus low PCE. On the other hand, these polymers also formed highly oriented edge-on structures on n(+)-Si/SiO2 substrates, which are suitable for high-performance field-effect transistors (FETs), and a fabricated FET device showed a hole mobility as high as 0.18 cm(2) V-1 s(-1).

DOI： 10.1039/c5py01878a

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Potential energy surface mapping was completed for the entire catalytic cycle of palladium-catalysed cyanoesterification onto norbornene (NBE) using density functional theory calculations. We found that after the oxidative addition step of the reagent methyl cyanoformate, the reaction proceeds through an insertion of olefin into a Pd-II-COOMe bond first. Subsequently, reductive elimination occurs by transferring the cyanide group from the Pd center to NBE. This rearrangement is triggered by the rotation of the ester group into a pi-interaction with the Pd-II centre. The regioselectivity of olefin insertion is controlled by ionic and covalent interactions in the precursor pi-complex formation step. Importantly, all of the intermediates and transition states along the exo pathway were found to be more stable than the corresponding structures of the endo pathway without any sign of crossing over between the two surfaces via isomerization. The rate-determining step is the reductive elimination despite the fact that the corresponding activation barrier is reduced by conformational changes via the rotation of a MeOOC-C(NBE) bond.

DOI： 10.1039/c6dt00341a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Direct chalcogenation of aryl C-H bonds has attracted a lot of attention because arylcharcogen compounds represent useful building blocks in bioactive molecules and functional organic materials. Very recently, chelate-assisted intermolecular direct thiolation and selenation have been developed using various transition-metal catalysts such as palladium, rhodium, nickel, copper and ruthenium. In addition, an appropriate choice of directing group can be used to control the reaction sites. This highlight review focuses on the recent advances in catalytic C-H chalcogenation.

DOI： 10.1039/c6dt02167k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

o-Bromobenzyl alcohol has been developed as a novel annulating reagent, bearing both nucleophilic and electrophilic substituents, for the facile synthesis of polycyclic aromatic hydrocarbons. A palladium/electron-deficient phosphine catalyst efficiently coupled o-iodobiphenyls or (Z)-,beta-halostyrenes with o-bromobenzyl alcohols to afford triphenylenes and phenanthrenes, respectively. The present cascade reaction proceeded through deacetonative cross-coupling and sequential intramolecular cyclization. An array of experimental data suggest that the reaction mechanism involves the equilibrium of 1,4-palladium migration.

DOI： 10.1021/acs.joc.5b01693

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Organic field-effect transistor (OFET) characteristics of phenanthrodithiophene (PDT)-isoindigo (IID) copolymers with different alkyl chains (12OD and BOBO) as an active layer, and their structure property relationships are described. The fabricated 12OD-based OFET device exhibited hole mobility of 0.16 cm(2)V(-1) s(-1). Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis revealed that 12OD formed highly ordered edge-on structure, whereas the BOBO film showed amorphous-like structure with no obvious pi-stacking crystallites. This may be attributed to a large steric hindrance of branched side chains in the BOBO polymer, which suppresses effective pi-pi overlaps between the adjacent polymer backbones.

DOI： 10.1246/cl.150357

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The synthesis;,characterization, and solar cell application of newly developed semiconducting polymers containing phenanthro[1,2-b:8,7-b']dithiophene (PDT) combined with A bis(thienyl)isoindigo (IID) unit are,described. The polymers with longer, alkyl Chains are sufficiently soluble to be compatible with the processes required to manufacture solar cells. In conventional solar cell, devices, polymers with all branched alkyl chains tend to form a higher proportion of a well-ordered face-on crystallite in the pi-stack direction than those with both linear and branched alkyl chains, which significantly improves the Ell factor (FF), resulting in higher power conversion efficiency (PCE). In terms of optimizing the alkyl chain lengths; the installation of longer alkyl side chains on the polymer backbone leads to low molecular weight polymer, which may promote a large phase separation. As a result, the polymers 12OD and BOBO, beating shorter alkyl groups, performed better, and a BOBO polymer-based solar cell (PSC) showed the best PCE value up to 3.83%. In the inverted PSCs, the polymers with all branched alkyl chains have a higher face-on ratio than those with both linear and branched alkyl chains. Because of their improved J(sc), inverted PSCs with BOBO/PC71BM gave the best performance, with a PCE up to 5.28%. Although an obvious dependence of photovoltaic properties on molecular order-was observed in conventional solar cell devices, no trend was observed in inverted cells, Possibly attributable to their amorphous nature, which arises from the axisymmetrical structure of PDT, leading to less effective pi-pi overlap and low crystallinity.

DOI： 10.1021/acs.macromol.5b00622

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

DOI： 10.1039/c5tc90044a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Synthesis, characterization, and polymer solar cell and transistor application of a series of phenanthro[1,2-b:8,7-b]dithiophene-based donor-acceptor (D-A)-type semiconducting polymers combined with a diketopyrrolopyrrole unit are reported. The present polymers showed some unique features such as strong aggregation behavior, high thermal stability, and short - stacking distance (3.5-3.6 angstrom), which are suitable for high performance organic materials. In addition, they have a significantly extended absorption up to 1000 nm with a band gap of ca. 1.2 eV. However, such strong intermolecular interaction reduced their solubility and molecular weights, which resulted in low crystalline nature and moderate field-effect mobility of 0.01 cm(2) V-1 s(-1). Furthermore, such strong aggregation behavior led to the large-scale phase separation in the blend films, which may prevent the effective photocurrent generation, limiting J(sc) and power conversion efficiency of 2.0%. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 709-718

DOI： 10.1002/pola.27500

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Field-effect transistors (FETs) have been fabricated with thin films of a series of 2,9-dialkylated phenanthro [1,2-b:8,7-b'] dithiophene derivatives (C-n-PDTs). The FET characteristics of C-n-PDT thin-film FETs with an SiO2 gate dielectric as well as high-k gate dielectrics were recorded, and the dependence of the field-effect mobility, mu, on the number (n) of carbon atoms in the alkyl chains was investigated, showing that the 2,9-didodecylphenanthro[1,2-b:8,7-b'] dithiophene (C-12-PDT) thin-film FET displays superior properties, with mu s as high as 1.8 cm(2) V-1 s(-1) for the SiO2 gate dielectric and 2.2 cm(2) V-1 s(-1) for the HfO2 gate dielectric. The average mu values, &lt;mu &gt;, reach 1.1(5) and 1.8(6) cm(2) V-1 s(-1), respectively, for the SiO2 and ZrO2 gate dielectrics. Low-voltage operation, showing an absolute average threshold voltage &lt;|V-th|&gt; of similar to 11 V, was implemented, together with the above high &lt;mu &gt; of similar to 2 cm(2) V-1 s(-1). Also, a flexible FET was fabricated with a parylene gate dielectric. The results of this study show the potential of the C-12-PDT molecule for application in a high-performance transistor.

DOI： 10.1039/c4tc02413c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHINESE CHEMICAL SOC  

A series of 3,10-dialkylated picenes has been synthesized from 3,10-dimethoxypicene through a divergent approach involving Ni-catalyzed alkynylation of a C-O bond, alkylation, and hydrogenation.

DOI： 10.1039/c5qo00039d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A palladium-catalyzed and picolinamide-directed C-H thiolation of naphthylamine derivatives with diaryl disulfides has been developed to provide a convenient route to 8-sulfenyl-1-naphthylamines. The reaction proceeds via a 5-membered palladacycle intermediates to afford the peri-thiolated products exclusively, in contrast to the conventional ortho-functionalization. Moreover, the related direct selenation was also achieved with diaryl diselenides, giving the corresponding selenated products with perfect site-selectivity.

DOI： 10.1021/jo502274t

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The radical addition of the ClS sigma-bond in sulfenyl chlorides to various CC triple bonds has been achieved with excellent regio- and stereoselectivity in the presence of a catalytic amount of a common iron salt. The reaction is compatible with a variety of functional groups and can be scaled up to the gram-scale with no loss in yield. As well as terminal alkynes, internal alkynes underwent stereodefined chlorothiolation to provide tetrasubstituted alkynes. Preliminary mechanistic investigations revealed a plausible radical process involving a sulfur-centered radical intermediate via iron-mediated homolysis of the ClS bond. The resulting chlorothiolation adducts can be readily transformed to the structurally complex alkenyl sulfides by cross-coupling reactions. The present reaction can also be applied to the complementary synthesis of the potentially useful bis-sulfoxide ligands for transition-metal-catalyzed reactions.

DOI： 10.1002/anie.201408121

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A direct selenation of inert C-H bonds of benzamide derivatives and their related compounds with diselenides has been achieved with the palladium catalyst. The reaction was compatible with a variety of functional groups, including a bromo group. Primitive mechanistic insights revealed that the reaction proceeded through a C H bond cleavage and the sequential oxidative addition of diselenides. The present synthetic method can be applied to the facile synthesis of selenoxanthone which can be regarded as promising heterocyclic materials.

DOI： 10.1021/ol502439m

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Language：English   Publisher：WILEY-V C H VERLAG GMBH  

The characteristics of field-effect transistors (FETs) fabricated from thin films and single crystals of phenacene molecules are fully reported in this review together with the electronic and crystal structures of phenacenes. Phenacene molecules possess a low HOMO level and a wide band gap. The highest mobility observed in the phenacene thin-film FETs is 7.4 cm(2)V(-1)s(-1) for [6]phenacene, and in single-crystal FETs the highest value is 6.3 cm(2)V(-1)s(-1) for [7]phenacene. The phenacene thin-film FETs show O-2-sensing properties unlike their single-crystal FETs. The bias-stress effect is fully investigated for phenacene single-crystal FETs. Furthermore, the low-voltage operation of phenacene single-crystal FETs with electric-double-layer (EDL) capacitors is reported. The temperature dependence of phenacene single-crystal FETs is reported to clarify the transport mechanism, which is suggestive of band-like transport.

DOI： 10.1002/ejic.201402168

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A variety of alpha-iminonitriles were formed as the minor products of three-component coupling reactions of arynes, isocyanides, and cyanoformates in the presence of the cationic palladium complex [Pd(NCPh)(2)(dppf)1(BF4)(2) as the catalyst, along with cyano-substituted iminoisobenzofurans as the major products. alpha-Iminonitriles obtained from this process are hardly accessible by conventional methods. In addition, when the isolated iminoisobenzofurans were treated with diisobutylaluminum hydride (DIBAL-H) or AlMe3, the transformation of cyano-substituted iminoisobenzofurans into alpha-iminonitriles was observed.

DOI： 10.1021/om500408h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Phenanthro[1,2-b:8,7-b']dithiophene (PDT) was prepared via Suzuki-Miyaura or Negishi cross-coupling of a 2-thienylboron or -zinc compound with 1,4-dibromobenzene, followed by Lewis acid-catalyzed regioselective cycloaromatization of the epoxide. A series of 2,9-dialkylated phenanthro[1,2-b:8,7-b']dithiophene (PDT) derivatives could also be synthesized in good yields by Suzuki-Miyaura coupling of the brominated PDT with alkylboranes by introducing linear alkyl substituents. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2014.05.035

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A series of picenes having methoxy groups was synthesized through Pd-catalyzed Suzuki-Miyaura couplings or Wittig reaction/intramolecular cyclization sequences, and their physicochemical properties and single-crystal structures were evaluated. The substitution position effects between the outer 1,12-, 2,11-, and 4,9-position and the inner 3,10-position are quite different; the former showed the same electronic structure as that of picene, but the latter results in a HOMO geometry different from those of picene and other methoxy picenes. In addition, crystal structures of four types of methoxy-substituted picenes 4a-c,e strongly depend on their substitution position and number of methoxy groups, which dramatically changes the structures from the fully anisotropic 1D pi-stacked structure to a unique 3D herringbone structure due to steric hindrance of methoxy groups. The calculations of transfer integrals based on their single-crystal structures reveal that the methoxy picenes have intermolecular overlaps less effective than that of the parent nonsubstituted picene. These results are attributed not only to the packing structure but also to electronic structures such as the HOMO distribution. The preliminary OFET of the representative 4c,e showed hole mobilities significantly lower than that of picene due to their less effective intermolecular overlaps, as predicted by the calculated transfer integrals.

DOI： 10.1021/jo500543h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

A catalytic variant of the direct thiolation of arenes, bearing directing groups, with disulfides or thiols has been developed under palladium and copper co-catalysis. Both sulfenyl moieties of the disulfide could be incorporated into the thiolated products, therefore, the reactions reached completion with only half an equivalent of disulfide, with respect to the starting arene. Experimental evidence suggested that the reaction proceeds through a Pd-II/Pd-IV mechanism.

DOI： 10.1002/chem.201304717

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Chlorothiolation of terminal alkynes with sulfenyl chlorides yields anti-adducts without transition-metal catalysts. In sharp contrast, transition-metal-catalyzed chlorothiolation has not been developed to date, possibly because organosulfur compounds can poison catalyst. Herein, the regio- and stereoselective palladium-catalyzed chlorothiolation of terminal alkynes with sulfenyl chlorides is described. syn-Chlorothiolation offers a complementary synthetic route to chloroalkenyl sulfides. 2-Chloroalkenyl sulfides can easily be transformed into various sulfur-containing products, most of which are often found in natural products and pharmaceuticals.

DOI： 10.1002/asia.201301295

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The synthesis of a series of gem- and vic-diborylated vinylsilanes was accomplished via highly selective transition-metal-catalyzed syn-dimetalation to the alkynylmetal species. This protocol served as a general synthetic method toward regio- and stereodefined multisubstituted olefins. The key steps are the diastereoselective Suzuki-Miyaura cross-coupling reactions of gem- and vic-diborylated vinylsilanes, in which the two boron groups showed discrete reactivities to afford diverse precursors of multisubstituted olefins.

DOI： 10.1021/jo4024057

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Platinum-catalyzed diborylation of phenylethynyl MIDA boronate with B-pin-B-pin proceeds to yield 1,1,2-triboryl-2-phenylethene with two different classes of the boron functionalities. Sequentially, the obtained 1,1,2-triboryl-2-phenylethene are subjected to Suzuki-Miyaura coupling to introduce a series of aryl groups chemoselectively to afford 1,1-boryl-2,2-diarylethenes.

DOI： 10.1021/ol403326z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A new picene-type molecule, phenanthro[1,2-b : 8,7-b'] dithiophene, has been synthesized for use in organic field-effect transistors (OFETs). The molecule consists of a phenanthrene core with two thiophene rings fused on the ends. This molecule can be recognized as a picene analogue. The electronic structure of the molecule was determined by its optical absorption spectrum together with a theoretical calculation based on density functional theory (DFT). The topological and electronic structures of thin films produced by direct thermal evaporation of the compounds and by deposition from a solution were characterized by optical imaging, X-ray diffraction, and atomic force microscopy. FET devices were fabricated with these thin films, and showed field-effect mobility as high as 10(-1) cm(2) V-1 s(-1).

DOI： 10.1039/c3ra44050h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Alkoxycarbonyl(chloro)(cyano)rhodium(III) complexes mer-[RhCl(CO2R)(CN)(PMe3)(3)] (1: R = Me; 2: R = Et; 3: R = Pr-n; 4: R = Pr-i; 5: R = Bu-n; 6: R = Bn) are prepared via oxidative addition of the corresponding cyanoformates to [RhCl(PMe3)(3)], derived in situ from [RhCl(cod)](2) and three equivalents of PMe3 in toluene at 70 degrees C, and their structures are characterized using NMR (H-1, C-13{H-1}, and P-31{H-1)) and X-ray diffraction.

DOI： 10.1246/cl.131072

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A series of cis-alkynyl(silyl)platinum(II) complexes was prepared via the chemoselective C(sp)-Si bond cleavage of alkynylsilanes by a platinum(0) complex ligated with the P-N hemilabile bidentate ligand. The coordination of the triple bond to the platinum center triggers selective C(sp) Si bond cleavage. Hammett plots of the P-31{H-1} NMR spectroscopic properties (delta and J values) reflect an electronic effect on platinum(II) complexes; trans substituents of arylethynyl groups are influenced, but cis-positioned silyl groups are not affected, as evidenced by Si-29{H-1} NMR. In comparison, Hammett plots show that C(sp) Si bond cleavage rates are accelerated by electron-rich alkynylsilanes, which is opposite to the ordinary oxidative addition of aryl halides to transition metals often observed in catalytic cross-coupling reactions. A DFT calculation reveals that intermediates and transition states are stabilized by electron-rich alkynylsilanes and that the five-membered hemilabile P-N ligand is essential, in which a reactive electron-deficient 14-electron platinum(0) species is produced via the dissociation of nitrogen, giving rise to a monodentate phosphine coordination. Electron-rich alkynylsilanes allow decreased pi back-donation from the platinum center to the ligand, accelerating the dissociation of the more labile nitrogen. Steric congestion between diisopropylphosphino and silyl groups thermodynamically disfavors C(sp)-Si bond cleavage.

DOI： 10.1021/om5002588

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

An efficient method for the direct conversion of cyano-substituted iminoisobenzofurans into their corresponding alkyl 2-cyanobenzoates has been developed. This transformation proceeds via cleavage of C-C, C-O, and C-N bonds in starting iminoisobenzofurans. DFT study revealed that intermediate a-iminonitriles are produced in situ via C-C bond formation between 2-iminium benzoates and a cyanide ion. Generation of isocyanide as the byproduct in a more thermodynamic manner in DFT calculations also supports the experimental results.

DOI： 10.1021/ol5026519

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A computational investigation has been carried out to elucidate the origin of the exclusive exo-selectivity in the Pd-catalyzed cyanoesterification of strained cyclic olefins, norbornene and norbornadiene. A hybrid density functional was selected for the level of theory with a triple-zeta quality basis set, which was proposed in an earlier study to provide an experimentally sound ground state electronic structure description for palladium(II) and palladium(IV) complexes from multi-edge X-ray absorption spectroscopic measurements. Given that the product of oxidative addition can be isolated, we focused on the olefin coordination as the earliest possible origin of exo-selectivity. The calculated geometric structure for the trans-Pd(CN)(COOR)(PPh3)(2) complex at the BHandHLYP/ def2TZVP/ PCM(toluene) level is in an excellent agreement with its experimental structure from crystallographic measurements. Upon dissociation of one of its phosphane ligands, the coordinatively unsaturated trans-isomer is only 17 kJ mol(-1) away from the isomerization transition state, leading to the 14-electron cis-isomers that are 17 to 37 kJ mol(-1) lower in energy than the trans-isomers. Regardless of the initial complex for olefin coordination, the exo-isomer for the norbornene complex is at least 8 kJ mol(-1) lower than the corresponding endo-isomer. The origin of this considerable difference in Gibbs free energy can be attributed to the remarkably different steric and agostic hydrogen interactions between the methylene and the ethylene bridges of the norbornene and the adjacent cis-ligands at the Pd-II center.

DOI： 10.1039/c4dt00839a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Treatment of o-iodobiphenyls with abromobenzyl alcohols in the presence of cesium carbonate under palladium catalysis affords a series of highly substituted triphenylenes. The reaction involves two C-C bond formations and C-C and C-H bond cleavages. A combination of palladium and an electron-deficient phosphine ligand proves to be effective for both decarbonylative cross-coupling and intramolecular cyclization.

DOI： 10.1021/oI4025869

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A highly regio- and stereoselective silylborylation of an alkynylboronate is disclosed. PhMe2Si-B-pin undergoes a Pd(OAc)(2)/(t)OctNC-catalyzed syn-addition to the alkynylboronate to yield 1-phenyl-1-silyl-2,2-diborylethene with high regioselectivity. The product 1-phenyl-1-silyl-2,2-diborylethene is then chemoselectively arylated by Suzuki-Miyaura coupling to afford (2)-1-silyl-2-borylstilbene derivatives. This approach is extended to the synthesis of a tetraarylated olefin with four different substituents.

DOI： 10.1021/ol401333j

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Synthesis of novel cyclic 1-alkenylboronates is accomplished through the zirconium-mediated regio- and stereoselective double functionalization of 1-alkynylboronates and the subsequent ruthenium-catalyzed ring-closing metathesis (RCM). The obtained substituted cyclic 1-alkenylboronates are transformed into o-terphenyl and triphenylene derivatives. © 2013 American Chemical Society.

DOI： 10.1021/ol400896u

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Palladium-catalyzed cross-coupling reaction of aryl- or alkenylboronic acids with acid chlorides in the presence of copper(I) thiophene-2-carboxylate (CuTC) as an activator in diethyl ether at room temperature under strictly non-basic conditions affords the diaryl ketones or chalcones in moderate to excellent yields. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring are compatible. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2013.01.058

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A series of unsymmetrical diarylethynes have been synthesized by the copper-catalyzed cross-coupling reaction of alkynylboronates with aryl iodides in high to excellent yields under palladium-free conditions. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring are compatible with this reaction. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2012.11.069

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

A series of substituted [6]phenacenes were synthesized through the Suzuki-Miyaura coupling and intramolecular double cyclization, using a polyhalobenzene and two different alkenylboronates. This methodology provides a direct route to unsymmetrical [6]phenacenes. The physicochemical properties of four [6]phenacenes were evaluated using UV-vis and fluorescence spectroscopies as well as cyclic voltammetry.

DOI： 10.1246/cl.130584

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel and versatile synthetic method for picene derivatives is developed using the Pd-catalyzed intramolecular double cyclization of the corresponding 2,3-bis[(1Z)-2-phenylethenyl]-1,4-dichlorobenzenes, which are readily prepared by Suzuki-Miyaura cross-coupling reactions of polyhalobenzenes with (Z)-arylethenylboronates. The physical properties of the obtained picenes can be modified via introducing a variety of functional groups to the picene frame-work All compounds are investigated by UV-vis and fluorescence spectroscopic measurements, CV, and DFT calculations as well as X-ray diffraction analysis.

DOI： 10.1021/ol401375n

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Iminoisobenzofuran derivatives have been prepared in moderate yields by the palladium-catalyzed three-component coupling reaction of arynes, isocyanides, and cyanoformates. This paper is dedicated to Professor Ei-ichi Negishi on the occasion of his 77th birthday.

DOI： 10.3987/COM-12-S(N)77

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Palladium/copper-cocatalyzed cross-coupling reactions of alkynylsilanes with aryl tosylates or mesylates afforded the corresponding unsymmetrical diarylethynes in moderate to good yields. The optimized reaction conditions to afford higher yields of cross-coupled products were found to be 5 mol % of [PdCl2(bpy)], 15 mol % of BrettPhos, and 10 mol % of (CuCl)-Cl-I in DMF as a solvent.

DOI： 10.1246/cl.2012.1503

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In this paper, we explore the copper/palladium-cocatalyzed cross-coupling reactions of 1-aryl-2-trimethylsilylethynes with aryl iodides, bromides, and chlorides as coupling partners, to furnish unsymmetrically disubstituted ethynes in moderate to excellent yields. Various aryl iodides were subjected to reaction under the optimized conditions with 5 mol % of Pd(PPh3)(2) and 50 mol % of CuCl. The steric properties of the aryl iodide proved more influential to the outcome of the cross-coupling reaction than electronic factors. In addition, we succeeded in synthesizing unsymmetrical diarylethynes using two different aryl iodides in one-pot. Furthermore, under the same reaction conditions with 10 mol % of PdCl2, 40 mol % of P(4-FC6H4)(3), and 50 mol % of CuCl as catalyst, we succeeded in synthesizing unsymmetrical diarylethynes from various aryl bromides. Finally, we explored reactions with aryl chlorides and duly discovered that unsymmetrical diarylethynes were obtainable in moderate to good yields when 10 mol % of Pd(OAc)(2), 10 mol % of (-)-DIOP, and 10 mol % of CuCl were used. These reactions proceed through a direct activation of a carbon silicon bond in alkynylsilanes by CuCl to generate the corresponding alkynylcopper species via transmetalation from silicon to copper. Mechanistic investigations on the reaction of alkynylsilanes with aryl bromides confirmed that the trimethylsilyl bromide generated in situ retarded both transmetalation steps between CuCl and alkynylsilane, and between palladium(II) species formed by oxidative addition and alkynylcopper species. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2012.03.093

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

beta-1,3-Dicarbonyl aldehydes were synthesized by iron-catalyzed oxidative reactions between 1,3-dicarbonyl compounds and two molecules of tertiary amines in the presence of tert-butyl hydroperoxide (TBHP). alpha,beta-Unsaturated aldehydes generated by tertiary amine oxidation In situ act as key intermediates under mild reaction conditions.

DOI： 10.1021/ol202749x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

An efficient and inexpensive catalytic system using a readily available CuCl/PPh3 combination for the catalytic cross-coupling reactions of alkynylsilanes with a variety of aryl iodides affords unsymmetrical diarylethynes in good to excellent yields.

DOI： 10.1246/cl.2011.972

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Carbonylative homocoupling of arylzinc compounds 1 using 1 atm of CO and 1,2-dibromoethane as an oxidant was achieved in the presence of Rh-dppf catalyst, affording symmetrical diaryl ketones in good yields. Under similar conditions, Pd or Ni catalysts induced oxidative homo coupling of 1 to yield biaryls instead. The beneficial catalysis by Rh in the carbonylation was presumed to stem from the facility by which the migration of the aryl ligand to CO at the Rh3+ intermediate occurred.

DOI： 10.1021/jo1025173

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A Ba-Ti composite oxide was formed on a NOx storage and reduction catalyst via impregnation of a Ba-Ti precursor solution composed of H2O2 added to a complex prepared using the citric acid method. The structure of the Ba-Ti composite in solution was analyzed by chemical composition analysis and FT-Raman and UV-vis spectroscopy. MM2 calculations were performed to propose its chemical structure. Both Ba and Ti together were found to form a composite molecule in the solution. Furthermore, TEM-EDX and XRD analyses of the Ba-Ti composite oxide on the catalyst prepared by impregnation with the Ba-Ti composite aqueous solution revealed that Ba and Ti in the catalyst were highly dispersed at the nm scale. The formation of the Ba-Ti composite oxide on the NSR catalyst enhanced sulfur desorption efficiency and led to high-performance NOX conversion as a NOX storage and reduction activity catalyst after desulfation treatment. It was assumed that the existence of nano-scaled Ba compounds combined with Ti was efficient for the inhibition of the sintering of barium sulfate and its facile decomposition. It was found that dispersion of Ba compounds for NOX storage materials using a Ba-Ti complex solution is an efficient way to improve the durability of NSR catalysts. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apcatb.2011.01.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

DOI： 10.1002/anie.201103601

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

3-Diphenylphosphino-2-(diphenylphoshino)methyl-2-methylpropyl acetate acted as an efficient ligand for a Rh catalyst, achieving cross-coupling between arylzinc compounds bearing electron-withdrawing groups and alkyl electrophiles. The beneficial effect of the tripodal ligand and such aryl nucleophiles was discussed with regard to the specificity of the Rh catalysis.

DOI： 10.1021/ol100210u

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

DOI： 10.1002/pola.23781

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Alkynylboronates can be employed as a practical and versatile precursor for a variety of pi-conjugated organic compounds. In the presence of Cu(I) salt, cross-coupling reactions of acid chlorides with alkynylboronates giving rise to the corresponding conjugated ynones takes place readily in aprotic polar solvents such as DMI under neutral conditions. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2009.11.001

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC SYNTHETIC ORGANIC CHEM JPN  

In this review, the results of studies on new methodology for bond activation by using transition metal complexes are described, in order to realize the expeditious and selective synthesis of organic compounds. Carbon-carbon bond formation reactions, accompanying with cleavage of unactivated bonds such as carbon-carbon, carbon-boron, and carbon-silicon bonds, are reported. This review involves, for examples, the new synthetic methodology to introduce both cyano and ester groups (cyanoesterification) via the C-C bond activation, regio- and stereoselective synthesis multi-substituted olefins mediated a zirconocene complex via the C-B bond activation, and cross-coupling reaction of alkynylsilanes activated by a copper salt via the C-Si bond cleavage. Each reaction can be applicable to synthesis of functional molecules such as opto-electronic materials, an anti-cancer agent, and liquid crystalline compounds.

DOI： 10.5059/yukigoseikyokaishi.67.889

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The palladium-catalyzed cross-coupling reactions of aryl iodides with alkynylsilanes in the presence of a substoichiometric amount (50 mol %) of copper(I) chloride as an activator in DMF under strictly non-basic reaction conditions afford the corresponding unsymmetrical diarylethynes in moderate to excellent yields. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring are compatible. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2009.05.112

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A series of novel multisubstituted vinylsilanes are prepared regio- and stereoselectively by carbozirconation of various alkynylsilanes through zirconacycles such as zirconacyclopropenes and zirconacyclopentenes and the subsequent transformation of the formed alkenylzirconocene complexes.

DOI： 10.1021/ol901236s

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Language：English   Publisher：ELSEVIER SCIENCE SA  

Reaction of HSi(OEt)(3) with IrCl(CO)(PPh3)(2) (5:1 molar ratio) at room temperature for 1 h gives IrCl(H){Si(OEt)(3)}(CO)(PPh3)(2) (1), which is observed by the H-1 and P-31{H-1} NMR spectra of the reaction mixture. The same reaction, but in 20:1 molar ratio at 50 degrees C for 24 h produces IrCl(H)(2)(CO)(PPh3)(2) (2) rather than the expected product Ir(H)(2){Si(OEt)(3)}(CO)(PPh3)(2) (3) that was previously reported to be formed by this reaction. Accompanying formation of Si(OEt)(4), (EtO)(3)SiOSi(OEt)(3), and (EtO)(2)HSiOSi(OEt)(3) is observed. On the other hand, trialkylhydrosilane HSiEt3 reacts with IrCl(CO)(PPh3)(2) (10:1 molar ratio) at 80 degrees C for 84 h to give Ir(H)(2)(SiEt3)(CO)(PPh3)(2) (4) in a high yield, accompanying with a release of ClSiEt3. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ica.2008.12.033

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The catalytic cross-coupling between ArZnX and ICH(2)(CH(2))(n)P(O)(OEt)(2) (n = 0-3) has been investigated to determine the utility of the Rh catalyst during the alkyl-aryl cross-coupling and to develop a new synthetic method for phosphoryl-substituted alkylarenes. Rh-dppf exhibits an excellent catalytic activity for the reaction with the alkylphosphonate of n = 1, whereas for the reaction with those of n = 2 or 3, P-hydride elimination mainly takes place. As for the reaction with an alkylphosphonate of n = 0, a polarity inversion of the coupling components is necessary in order to provide the coupling products; the phosphoryl analogue of the Reformatsky reagent and ArI give the cross-coupling products in good yields through the catalysis by Rh-dppf.

DOI： 10.1021/jo900142b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Graphitic carbon nitride (g-C(3)N(4)) with a band gap of 2.7 eV is studied as a nonmetallic photocatalyst for H(2) or O(2) evolution from water under ultraviolet (UV) and visible light. The g-C(3)N(4) catalyst exhibits activities for water reduction into H(2) or water oxidation into O(2) in the presence of a proper sacrificial electron donor or acceptor, respectively, even without the need for precious metal cocatalysts. When bis(1,5-cyclooctadiene)platinum complex [Pt(cod)(2)] (a nonionic complex) is used as a precursor of Pt cocatalyst instead of H(2)PtCl(6) (an ionic complex), enhanced H(2)) evolution activity is acquired. This difference in activity is primarily due to the better dispersion of Pt nanoparticles on g-C(3)N(4), which is considered to originate from the better access of Pt(cod)(2) to the g-C(3)N(4) surface, as compared to that of H(2)PtCl(6) in the preparation process. Unmodified g-C(3)N(4) produces O(2) from an aqueous silver nitrate solution upon UV irradiation (lambda &gt; 300 nm), although N(2), release due to self-decomposition of g-C(3)N(4) by photogenerated holes takes place. Modification of g-C(3)N(4) with RuO(2), improves not only O(2) evolution activity but also stability against the self-decomposition, resulting in stable visible-light-driven O(2) evolution (lambda &gt; 420 nm).

DOI： 10.1021/jp809119m

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

DOI： 10.1002/pola.23070

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

The palladium/copper-cocatalyzed sila-Sonogashira cross-coupling reactions of activated aryl chlorides with alkynylsilanes under strictly nonbasic conditions yield the unsymmetrical diarylethynes in moderate to good yields.

DOI： 10.1055/s-0028-1087345

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Language：English   Publisher：JOHN WILEY & SONS INC  

Doubly functionalized polar norbornenes 3a-3g substituted by both a variety of ester and cyano groups were polymerized by ring-opening metathesis polymerization (ROMP) with a Ru carbene complex 2 bearing 3-bromopyridine as a ligand (third generation Grubbs' catalyst) in a living manner. The successive hydrogenation of the main-chain double bond in the synthesized living ROMP polymers 4a-4g with a hydridoruthenium complex was exploited. The comparison of thermal properties of a series of ring-opening metathesis polymers 4a-4g with those of their hydrogenated derivatives 5a-5g revealed the decrease of glass transition temperatures (T-g) but little change of the 5% decomposition temperature (T-d(5)). In all cases examined in this study, a decrease of T-g by hydrogenation was around 20-40 degrees C, regardless of the ester substitutents. In the presence of the additional PCy3, triethylamine, and methanol after complete consumption of monomer 3a under the living ROMP condition, the tandem ROMP-hydrogenation of the resulting polymer 4a generated in situ was attained under a H-2 (9.8 MPa) atmosphere at 80 degrees C to afford the hydrogenated polymer 5a, retaining the narrow polydispersity of 1.03. (C) 2008 Wiley Periodicals, Inc.

DOI： 10.1002/pola.22671

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

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Pd-P(t-BU)(3) was found to be a chemoselective catalyst for the reaction of p-phenylenedizinc compound with equimolar amounts of carbon electrophiles to afford the single cross-coupling products in good yields, effectively suppressing the formation of double cross-coupling products. The subsequent additions of other electrophiles to the resulting solutions caused the second cross-coupling of the incipient products to take place, achieving a novel and efficient one-pot synthesis of unsymmetrically 1,4-disubstituted benzenes. The origin of the observed high chemoselectivity was speculated.

DOI： 10.1021/jo702103r

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Multisubstituted olefins are efficiently prepared by the zirconocene-mediated regio- and stereoselective coupling between 1alkynylboronates and ethylene, followed by sequential transformation in moderate to high yields. The proper combination of substrates and reaction conditions is important for high yields. The synthesis of various tetra substituted alkenes in a regio- and stereocontrolled manner is described. This methodology has been applied to the synthesis of (Z )-tamoxifen in a concise, regio and stereoselective manner. This multicomponent coupling strategy involves the characteristics of 1-alkynylboronates toward high selectivities followed by palladium(O)-mediated cross-coupling with aryl halides.

DOI： 10.1021/ja075234y

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Language：English   Publisher：AMER CHEMICAL SOC  

Alkoxycarbonyl(cyano)palladium(II) complexes trans-Pd(COOR)(CN)(PPh3)(2) (1, R = Me; 2, R = Et; 3, R = Pr-n; 4, R = Pr-i; 5, R = Bu-n; 6, R = Bu-t; 7, R = Bn) are prepared via oxidative addition of the corresponding cyanoformates to Pd(PPh3)(4) in toluene at room temperature or 50 degrees C and characterized by means of NMR (H-1, C-13{H-1}, and P-31{H-1}) and IR spectroscopy as well as elemental analyses. X-ray crystallography of 3, 4, and 6 showed a square-planar coordination around the Pd center that is bonded to alkoxycarbonyl and cyano ligands in the trans configuration. The Pd-CN and Pd-COOR bonds in 1, 3, 4, and 6 are similar to those of the cyanopalladium(II) and alkoxycarbonylpalladium(II) complexes reported to date. On reaction of Pd(PPh3)(4) with phenyl cyanoformate a thermally induced ligand exchange takes place to afford the dicyanopalladium(II) complex, trans-Pd(CN)(2)(PPh3)(2) (8). Complex 2 is able to catalyze the reaction of norbornadiene with ethyl cyanoformate to produce (2R*,3S*)-ethyl 3-cyanobicyclo[2.2.1]hept-5-ene-2-carboxylate (13) and is recovered after the reaction. This observation supports the identification of alkoxycarbonyl(cyano)palladium(II) complexes as intermediates in the catalytic cycle of cyanoesterification of norbornene derivatives.

DOI： 10.1021/om700343y

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ARKAT USA INC  

Treatment of 1,1,3,3-tetrakis(alkylthio)-2-silapropanes with t-BuLi in THF at -40 degrees C generated 1,1,3,3-tetrakis(alkylthio)-1,3-dilithio-2-silapropanes which reacted with various bifunctional chlorosilanes to give the corresponding 4- to 7-membered polysilacycloalkanes in moderate to good yields. Furthermore, double alkylation of the dilithiated silanes with bis(halomethyl)diorganosilanes or dihaloalkanes was found to proceed smoothly giving rise to 1,4-disilacyclohexanes or silacycloalkanes in good yields, respectively, in THF and an aprotic polar co-solvent such as hexamethylphosphoric triamide (HMPA) or 1,1,3,3-tetramethylurea (TMU). The sulfenyl groups in the cyclized products were smoothly removed by radical reduction with tributyltin hydride.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

Exo-ethyl 3-cyanobicyclo[2.2.1]hept-5-ene-2-carboxylate (A) and exo-(n)butyl 3-cyanobicyclo[2.2.1]-hept-5-ene-2-carboxylate (B) bearing both cyano and ester groups were subjected to homopolymerization by ring-opening metathesis polymerization with a well-defined Ru catalyst, (H(2)IMes)(3-bromopyridine)(2)Cl2Ru=CHPh (3) (H(2)IMes = N,N'-bis(mesityl)-4,5-dihydroimidazol-2-ylidine) at low temperature. The characterization of the synthesized homopolymers by GPC analyses showed a value of a number-average molecular weight (Mn) as high as 296,000 and a narrow polydispersity index (&lt; 1.06). The results imply that the initiator 3 had a compatibility of the polar functional groups and promoted fairly well-defined living polymerization. The glass transition temperatures of the homopolymers obtained from monomer A were significantly higher than those observed for polymers from monomer B obtained under the same reaction conditions. The rates of homopolymerizations of monomer A, B, and the parent norbornene (C) were determined by the monitoring the consumption of the monomers by the H-1 NMR spectra. It was revealed that the polymerization rate for the homopolymerization of monomer A was almost same as that of monomer B, but much slower than that of C. On the basis of the successful homopolymerization, the synthesis of block and random copolymers derived from monomers A, B, and C via living polymerization using catalyst 3 was also accomplished.

DOI： 10.1295/polymj.PJ2006129

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Addition of cyanoformates (NC-COOR) to norbornene at 110 degrees C in the presence of Pd(PPh(3))(4) (10 mol %) as a catalyst affords with high selectivity the corresponding doubly functionalized polar norbornane derivatives bearing both cyano and ester groups. By using benzonorbornadiene and norbornadienes as the substrates, the reaction can be extended to synthesis of various functionalized norbornene derivatives in moderate to excellent yields. In most cases alkyl groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, and benzyl in the ester functionalities are applicable to the reactions. Oxidative addition of cyanoformates to Pd(0), insertion of norbornenes, and reductive elimination of the corresponding adducts constitute the proposed catalysis pathway. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2006.08.025

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ma061781c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

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Rh-dppf was found to be an efficient catalyst for the cross-coupling between primary alkyl halides bearing beta-hydrogens and arylzinc compounds possessing carbonyl groups such as ester, amide, or ketone at the ortho position. Various functional groups such as ester, nitrile, or acyloxylate moieties on the halides were tolerated under the catalysis conditions. Arylzinc compounds free of ortho-carbonyl groups reacted well with ethyl 3-iodopropanoate, suggesting that the essential intramolecular interaction between carbonyl groups and Rh promotes the reductive elimination.

DOI： 10.1021/ol060969d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

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The catalytic activity of a Rh complex in cross-coupling between ArZnI and TMSCH2I was examined in which the Rh complex, generated in situ from [RhCl(1,5-cyclooctadiene)](2) and 1,1'-bis(diphenylphosphino)ferrocene, exhibited excellent catalytic activity for the production of various functionalized benzylsilanes in good yields. From P-31 NMR studies of various solutions containing several of the reaction components, confirmation of the rapid and quantitative transfer of aryl groups from ArZnI to the Rh complex to form arylrhodium species was ascertained. A catalytic cycle, commencing with the transmetalation, was thus proposed for the reaction.

DOI： 10.1021/jo0520994

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Alkynylboronates are employed as a practical and versatile precursor for a variety of it-conjugated organic compounds. In the presence of a Cu(I) or Cu(II) salt, transformation of alkynylboronates into the corresponding 1,3-diynes upon exposure to air takes place readily in aprotic polar solvents such as DMI. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2005.10.056

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

2-Phenyl-1-methylenecyclopropane is isometized into 2-phenyl-1,3-butadiene and 1-phenyl-1,3-butadiene in the presence of catalytic amounts of RhH(CO)(PPh3)(3) and RhH(PPh3)(4). The Rh-containing product of the reactions has a 2-phenyl-1-methylallyl (or 1-phenyl-1-methylallyl) ligand, and is formed also from the reaction of 2-phenyl-1,3-butadiene with RhH(CO)(PPh3)(3). RhH(CO)(PPh3)(3) promotes ring-opening isomerization of 4-phenyl-1-methylenespiro[2,2]pentane to afford Rh[eta(3)-anti-CH2C{C(=CH2)Ph}CHCH3](PPh3)(2) (2) at 50 degrees C and Rh{kappa(1),eta(2)-CH2CH(Ph)C(=CH2)CH=CH2}(CO)(PPh3)(2) (3) at -35 degrees C. X-ray crystallography of 2 shows the pi-allylic ligand having a methyl group at anti position. The mechanism for formation of 2 via intermediate 3 is discussed. (c) 2005 Elsevier B.V All rights reserved.

DOI： 10.1016/j.molcata.2005.06.045

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Reaction of PPh2H with Pd(PPh3)(4) in a 4:1 molar ratio produced the Pd complex with two diphenylphosphine ligands, Pd(PPh2H)(2)(PPh3)(2) (1). Complex (1) was characterized by n.m.r. (H-1 and P-31{H-1}) spectra as well as by elemental analysis. Reaction of (1) with RhCl(PPh3)(3) yielded a Pd-Rh heterobimetallic complex with bridging phosphide ligands, formulated as [(Ph3P)(2)Pd(mu-PPh2)(2)Rh(PPh3)(2)]Cl (2).

DOI： 10.1007/s11243-005-6408-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

1,4-Bis(dimethylsilyl) benzene reacted with [Pt3H(PEt3)(3)(mu-PPh2)(3)] at room temperature to yield trinuclear Pt complex [Pt-3(SiMe2C6H4SiMe2H)(PEt3)(2) (mu-PPh2)(3)] (1a). Heating a solution containing an equimolar mixture of [Pt3H(PEt3)(3)mu PPh2)(3)] and 1a at 60 degrees C produced a hexanuclear Pt complex [(PEt3)(2)( mu-PPh2)(3)Pt-3(SiMe2C6H4SiMe2)Pt-3(PEt3)(2)(mu-PPh2)(3)] (2a). Complex 1a was characterized by X-ray crystallography and NMR spectroscopy, while the structure of 2a was determined by X-ray crystallography of single crystals containing 2a and [Pt3H2(PEt3)(2)(mu-PPh2)(4)] in 1:1 ratio. [Pt-3(SiMe(2)fcSiMe(2)H)(PEt3)(2)( mu-PPh2)(3)] (fc = Fe(eta(5)-C5H4)(2)) (1b) and [(PEt3)(2) (mu-PPh2)(3)Pt-3(SiMe(2)fcSiMe(2))Pt-3(PEt3)(2)(mu-PPh2)(3)] (2b) were obtained similarly from the reactions of 1,1 '-bis(dimethyisilyl)ferrocene with [Pt3H(PEt3)(3)(mu-PPh2)(3)] and characterized by NMR spectroscopy and elemental analyses. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jorganchem.2005.05.030

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG KG  

The palladium-catalyzed cross-coupling reactions of acid chlorides with arylboronic acids in the presence of copper(l) thiophene-2-carboxylate (CuTC) as an activator under strictly nonbasic and mild reaction conditions afford the unsymmetrical ketones in moderate to excellent yields. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring is compatible.

DOI： 10.1055/s-2005-872661

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The reactions of arylboronic acids with transPtPh(I)(PMe2Ph)(2) afford new arylboronato platinum complexes, trans-PtPh(OB(OH)Ar)(PMe2Ph)(2), and diarylplatinum complexes, trans-PtPh(Ar)(PMe2Ph)(2).

DOI： 10.1021/om049050t

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

[IrH(CO)(PPh3)(3)] promotes ring opening of 2-phenyl-l-methylenecyclopropane at room temperature to produce the Ir complex with a chelating 2-phenyl-3-butenyl ligand, [Ir{eta(2)-CH2CH(Ph)CH=CH2-kappa C-1}(CO)(PPh3)(2)] (1). The reaction of excess 2-phenyl-l-methylenecyclopropane with [IrH(CO)(PPh3)(3)] at 50 degrees C yields [Ir{eta(2)-(o-C6H4)CH(Me)CH= CH2-kappa C-1)(CO)(PPh3)(2)] (2), accompanied by the formation of 1-phenyl-1,3-butadiene and 2-phenyl-1.3-butadiene. 2,2-Diphenyl-l-methylenecyclopropane reacts with [IrH(CO)(PPh3)(2)] to afford [Ir{eta(2)-CH2-CPh2CH=CH2-kappa C-1}(CO)-(PPh3)(2)] (3) at 50 degrees C and [Ir{eta(2)-(o-C6H4)CMe(Ph)CH=CH2-kappa C-1)(CO)(PPh3)(2)] (4) at 100 degrees C. Heating a solution of 3 at 100 degrees C also forms 4 quantitatively. X-ray crystallography of 3 reveals a penta-coordinated structure around the Ir center bonded to a chelating 2,2-diphenyl-3-butenyl ligand. The reactions of 2,2-diphenyl-l-methylenecyclopropane and of 2,2-di(4-fluorophenyt)-1-methylenecyclopropane with [RhH(CO)(PPh3)(3)] at room temperature yield [Rh{eta(2)- CH2CAr2CH=CH2-kappa C-1}(CO)(PPh3)(2)] (5a: Ar = Ph, 5b: Ar = C6H4-F-4). The reactions at 50 degrees C cause ring opening of the substrate and orthometalation of the phenyl group to afford [Rh{eta(2)-(o-C6H4)CMe(Ph)CH=CH2-kappa C-1}-(CO)(PPh3)(2)](6a) and [Rh{eta(2)-(o-C6H3-F-4)CMe(C6H4-F-4)CH=CH2-kappa C-1}(CO)(PPh3)(2)](6b), respectively. Formation of 1,1-diaryl-1,3-butadiene is observed during the reaction. Heating a solution of 5a at 50 degrees C produces 1,1-diphenyl-1,3-butadiene and an allylrhodium complex, 8, rather than 6a, although the reaction of excess 2,2-diphenyt-1-methylenecyclopropane with 5a at 50 degrees C affords 6a in 60 %. The mechanisms of the above reactions are discussed based on the products and reaction rates. Coordination of P(OMe)(3) to the Rh center of 5a causes insertion of the CO ligand into the Rh-C bond to afford [Rh{eta(2)-CO-CH2CPh2CH=CH2-kappa C-1}(P(OMe)(3))(3)] (7).

DOI： 10.1246/bcsj.78.1469

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Reactions of PPh2H with [M(PCy3)(2)] (M = Pt, Pd) produce the dinuclear complexes with bridging PPh2 ligands of these metals, [{Pt(H)(PCy3)}(2)(mu-PPh2)(2)] and [{Pd-(PCy3)}(2)(mu-PPh2)(2)], respectively.

DOI： 10.1246/bcsj.78.1288

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Palladium-catalyzed cyanoesterification of norbornenes proceeds stereoselectively via NC-Pd-COOR (R = Me and Et) complexes as intermediates.

DOI： 10.1021/ol050749k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

(2,4,6-Trifluorophenyl)- and (2,6-difluorophenyl)boronic acids react with PdI(C6H4O4-Me)(tmen) (tmen = N,N,N',N'-tetramethylethylenediamine) in the presence of Ag2O to produce cis-diarylpalladium complexes with a tmen ligand via intermolecular transfer of the fluorophenyl group from B to Pd. The isolated complexes undergo coupling of the two aryl ligands upon heating the solution to 45-60 degreesC to afford unsymmetrical biaryls.

DOI： 10.1021/om049217i

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Language：English   Publisher：AMER CHEMICAL SOC  

2,2-Bis(2-phenylethyl)-1-methylenecyclopropane reacts with RhH(CO)(PPh3)(3) at room temperature and with IrH(CO)(PPh3)(3) at 70 degreesC to form the 3-butenyl complexes of these metals, M{eta(1):eta(2)-CH2C(CH2CH2Ph)(2)CH=CH2}(CO)(PPh3)(2) (1, M = Rh; 2, M = Ir). Heating 1 at 55 degreesC liberates 1,1-bis(2-phenylethyl)-1,3-butadiene, while the thermal reaction of 2 at 110 degreesC forms a mixture of 3-methyl-3-vinyl-1,5-diphenyl-1-pentene (48% NMR yield) and 3-methyl-3-vinyl-1,5-diphenylpentane (15% NMR yield). The reactions of excess amounts of 2,2-bis(2-phenylethyl)-1-methylenecyclopropane with RhH(CO)(PPh3)(3) at 55 degreesC and with IrH(CO)(PPh3)(3) at 115 degreesC afford the alkenyl complexes trans-Rh{(Z)-CH=CHC(CH2CH2Ph)(2)CH3}-(CO)(PPh3)(2) (3) and trans-Ir{(E)-CH=CHC(CH2CH2Ph)(2)CH3}(CO)(PPh3)(2) (4), respectively. The reaction mechanisms are discussed on the basis of the results of the reactions under different conditions. HCequivalent toCC(CH2CH2Ph)(2)CH3 reacts with MH(CO)(PPh3)(3) (M = Rh, Ir) to afford the alkynyl complexes trans-M{Cequivalent toCC(CH2CH2Ph)(2)CH3}(CO)(PPh3)(2) (5, M = Rh; 6, M = Ir) via oxidative addition of the C(alkyne)-H bond to the metal center and subsequent elimination of H-2.

DOI： 10.1021/om049632a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Ar-B(OH)(2) (1a: Ar = C6H4OMe-4, 1b: Ar = C6H3Me2-2,6) react immediately with Rh(OC6H4Me-4)(PMe3)(3) (2) in 5 : 1 molar ratio at room temperature to generate [Rh(PMe3)(4)](+)[B5O6Ar4](-) (3a: Ar C6H4OMe-4, 3b: Ar = C6H3Me2- 2,6). p-Cresol (92%/Rh), anisole (80%/Rh) and H2O (364%/Rh) are formed from 1a and 2. The reaction of 1a with 2 for 24 h produces [Rh(PMe3)(4)](+)[B5O6(OH)(4)](-) (4) as a yellow solid. This is attributed to hydrolytic dearylation of once formed 3a because the direct reaction of 3a with excess H2O forms 4. An equimolar reaction of 2 with phenylboroxine (PhBO)(3) causes transfer of the 4-methylphenoxo ligand from rhodium to boron to produce [Rh(PMe3)(4)](+) [B3O3Ph3(OC6H4Me-4)](-) (5). Arylboronic acids 1a and 1b react with Rh(OC6H4Me-4)(PR3)(3) (6: R = Et, 8: R = Ph) and with Rh(OC6Me-4)(cod)(PR3) (11: R = Pr-i, 12: R = Ph) to form [Rh(PR3)(4)](+)[B5O6Ar4](-) (7a: R = Et, Ar = C6H4OMe-4, 7b: R = Et, Ar = C6H3Me2-2,6, 9a: R = Ph, Ar = C6H3Me2-2,6) and [Rh(cod)(PR3)(L)](+)[B5O6Ar4](-) (13b: R = Pr-i, L = acetone, Ar = C6H3Me2-2,6,14a: R = Ph L = PPh3, Ar = C6H4OMe-4, 14b: R = Ph, L = PPh3, Ar - C6H3Me2-2,6), respectively. Hydrolysis of 14a yields [Rh(cod)(PPh3)(2)](+)[B5O6(OH)(4)](-) (15) quantitatively.

DOI： 10.1039/b315902g

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RhI(PPh3)(3) or [RhI(cod)](2) (cod = 1,5-cyclooctadiene) as a catalyst delivers both (Z)- and (E)-alkenylsilanes in the stereodivergent hydrosilylation of terminal alkynes with heteroatom-substituted organosilane reagents. Treatment of the rhodium catalyst and the silane reagent followed by addition of terminal alkyne at room temperature leads to (Z)-silanes, while addition of the silane and the alkyne to the rhodium catalyst in one portion and heating at 60 degreesC affords (E)-silanes highly selectively. The obtained (E)- and (Z)-alkenylsilanes bearing heteroatom substituents on the silicon atom are subjected to the palladium-catalyzed cross-coupling reaction with aryl halides to form a carbon-carbon bond with retention of stereochemistry. The stereodivergent hydrosilylations are applied to the polyaddition with bifunctional alkynes (1,3- and 1,4-diethynylbenzene) and silanes (1,3- or 1,4-bis(dimethyl-silyl)benzene), giving silicon-containing polymers, poly(aryleneethenylenesilylene)s, in highly stereocontrolled manners. A fluorine-containing silicon reagent bearing a 3,3,3-trifluoropropyl group is also subjected to the polymerization, in which [RhI(cod)12 is found to be an efficient catalyst. Measurement of UV-vis absorption/emission spectra and several. thermal analyses of the polymers are also conducted.

DOI： 10.1021/om049922r

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The reaction of Ph2PH with Pt(PEt3)(3) in 2:1 molar ratio produces the linear triplatinum Complex [Pt3H2(mu-PPh2)(4)(PEt3)(2)] (1). X-ray crystallography of I shows the structure of the complex with two PEt3 ligands at anti positions, while it exists as a mixture of the isomers with PEt3 at anti and syn positions. Pt(PEt3)(3) reacts with equimolar Ph2PH to afford the dinuclear complex [Pt2H2(mu-PPh2)(2)(PEt3)(2)] (2) and the cyclic trinuclear complex [Pt3H(mu-PPh2)3(PEt3)31 (3) depending on the reaction conditions. A dinuclear platinum(II) complex with a structure similar to 2, [Pt2H2(mu-(PBu2)-Bu-t)(2)(PEt3)(2)] (4), is obtained by the reaction of (t)-Bu2PH with Pt(PEt3)(3). Isolated complexes 2 and 3 cleanly react with Ph2PH to form 1, indicating that the reaction of Ph2PH with Pt(PEt3)(3), giving 1, involves these complexes as the intermediates. Complex 3 contains a triangular Pt-3 core with Pt-Pt bonds in the range 2.9784(4)-2.9983(3) Angstrom, as shown by X-ray crystallography. The H-1 NMR spectrum of 3 exhibits the hydrido signal at delta - 7.98 accompanied by splitting due to H-P and H-Pt coupling. Complex 3 reacts with Ph3SiH and Ph2SiH2 to give silylplatinum complexes [Pt-3(SiHn+1Ph4-n)(mu-PPh2)(3)(PEt3)(2)] (5, n = 1; 6, n = 2). Cationic triangular complexes [Pt-3(mu-PPh2)(3)(PEt3)(3)]I-+(-) (7) and [Pt-3(mu-PPh2)(3)(PEt3)(3)](+)[B4O4Ar4(OH)](-) (8, Ar = C6H4Me-4; 9, Ar = C6H4F-4; 10, Ar = C(6)H(4)CF(3-)4) are obtained from the reactions of complex 3 with MeI and with ArB(OH)(2), respectively.

DOI： 10.1021/om034131v

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The reactions of 2,4,6-trifluorophenylboronic acid with aryl(iodo)palladium(II) complexes, trans-Pd(C6F5)I(PR3)(2)(PR3 = PEt3, PMe2Ph, PMePh2) in the presence of Ag2O afforded transPd(C6F5)(2,4,6-C6F3H2)(PR3)(2) which are stabilized by fluorine atoms in the ortho positions.

DOI： 10.1039/b308741g

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Two anionic complexes of Au(III) with the bioligand biuret, cis-[Au(Biu)X-2](-) (BiuH(2)=biuret, X=Cl, Br), have been synthesized and characterized. The molecular structure of cis-[Au(Biu)Br-2]PPh4 has been determined by X-ray diffraction analysis. The complex anion has square-planar geometry with one deprotonated biuret dianion coordinated bidentately to the metal center via the terminal amino nitrogen atoms and two bromide ions in cis positions. There are no significant intermolecular Au-Au interactions in the solid state. Ab initio calculations of the geometric structure at different computational levels for biuret and both anionic complexes as well an IR study of the structures obtained are performed.

DOI： 10.1080/0095897031000069049

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PtI2(PPh3)(2) catalyzes hydrosilylation of 2,2-diphenyl-1-methylenecyclopropane with HSiEt3, HSiPh3, HSiEt2Ph, HSiPhCl2, and HSiCl3 under solvent-free conditions at 140 degreesC to produce the silyl compounds with a (2,2-diphenyleyclopropyl)methyl substituent in moderate to high yields without ring-opening of the substrate. PtI2(PPh3)(2) is converted by the reaction into PtH(I)(PPh3)(2), which also catalyzes the hydrosilylation of the methylenecyclopropanes. The reaction of 2-phenyl-1-methylenecyclopropane, 2-methyl-2-phenyl-1-methylenecyclopropane, 2,2-diphenethyl-1-methyl-enecyclopropane, and alkylidenecyclopropanes with HSiEt3 catalyzed by PtI2(PPh3)(2) causes addition of hydrosilane to the substrate accompanied by ring-opening. 2,2-Diphenyl-1-methylenecyclopropane undergoes ring-opening isomerization in the presence of HSi(OEt)Me-2 and Pt(PEt3)(3) catalyst to give 1,1-diphenyl-1,3-butadiene. The pathways for the hydrosilylation and the isomerization are discussed.

DOI： 10.1021/jo020293+

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The reactions of (4-methoxyphenyl)boronic acid (1a) and of (2,6-dimethylphenyl)boronic acid (1 b) with (PMe3)(3)Rh-(OC6H4Me-4) (2) in a 5:1 molar ratio result in the formation of cationic rhodium complexes with new tetraarylpentaborates [Rh(PMe3)(4)](+)[B5O6Ar4](3a, Ar = C6H4OMe-4; 3b, Ar = C6H3Me2-2,6). The characterization of 3a is as follows: orthorhombic space group P2(1)2(1)2(1), a = 14.7600(5) Angstrom, b =17.1675(5) Angstrom, c = 19.8654(5) Angstrom; V = 5033.7(3) Angstrom(3); Z = 4. The characterization of 3b is as follows: orthorhombic space group Pnma, a = 23.704(6) Angstrom, b = 17.254(8) Angstrom, c = 13.304(2) Angstrom; V = 5441(2) Angstrom(3); Z = 4. An intermediate complex, [Rh(PMe3)(4)](+)[Ph3B3O3(OC6H4Me-4)](-) (4), was isolated from the reaction of phenylboroxine, (PhBO)(3), with 2. The tetraarylpentaborates smoothly undergo hydrolysis to give [Rh(PMe3)(4)](+)[B5O6(OH)(4)](-) (5).

DOI： 10.1021/ic015630w

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PtI2(PPh3)(2)-catalyzed hydrosilylation of 2.2-diphenyl-1-methylenecyclopropane with HSiEt3 forms (2,2-diphenylcyclopropyl)methyl(triethyl)silane in 87% yield as a sole product. This highly selective addition of Si-H bond converts 2,2-diaryl-1-methylenecyclopropane into its silylated derivative without ring-opening. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4039(02)00165-X

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Silylrhodium(III) complexes RhX(H)((SiRnR3-n2)-R-1)(PPh3)(2) (1: X = I, R-1 = OSiMe3, R-2 = Me, n = 1; 2: X= I, R-1 = OEt,n = 3; 3: X = I, R-1 = OEt, R-2 = Me, n = 2; 4: X=I, R-1 = OEt, R-2 = Me, n = 1; 5: X= Cl, R-1 = OSiMe3, R-2 = Me, n = 1; 6: X = Cl, R-1 = OEt, n = 3; 7: X = Cl, RI = OEt, R2 = Me, n = 2; 8: X = Cl, R-1 = OEt, R-2 = Me, n = 1) were prepared by oxidative addition of (HSiRnR3-n2)-R-1 to RhX(PPh3)(3) and characterized by means of NMR (H-1, C-13{H-1}, P-31{H-1}, and Si-29{H-1}) and IR spectroscopy as well as elemental analyses. X-ray crystallography of 1, 2, and 6 showed a distorted square-pyramidal coordination around the Rh center that is bonded to the silyl ligand at the apical position and to halo and hydrido ligands in trans positions in the basal plane. The Rh-Si bonds in 2 and 6 are the shortest among Rh-Si bonds of the silylrhodium complexes reported to date. Si-29{H-1} NMR spectra of 1-8 show that the J(RhSi) value increases with an increase in the number of alkoxy substituents on the Si atom. Complex 2 reacted with HSiMe2(OSiMe3), HSi(OEt)(2)Me, and HSi(OEt)Me-2, respectively, to cause exchange of the silyl group between the Rh complex and the organosilane, forming an equilibrium mixture. Complexes 5-8 undergo thermally induced coupling of their chloro and triorganosilyl ligands at 60 degreesC to liberate the respective chloro(triorgano)silane. The reaction obeys first-order kinetics in the Rh complex with the observed rate constants in the order 5 congruent to 8 &gt; 7 &gt; 6. The OEt groups at the Si retard the coupling of chloro and triorganosilyl ligands significantly. Formation of ISiMe2(OEt)(2) from 4 takes place at a slightly slower rate than the reaction of 6, while complexes 2 and 3 do not undergo coupling of their iodo and silyl ligands at 60 degreesC.

DOI： 10.1021/om010862o

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL RESEARCH COUNCIL CANADA  

Isomerization of (E)-2-phenylethenylsilanes to the (Z)-isomers is found to easily take place at 60 degreesC within 1 h using 20-100 mol% of a hydrosilane and 0.1 mol% of RhI(PPh3)(3) and is understood in terms of insertion of alkenylsilanes to hydridorhodium followed by beta -hydride elimination.

DOI： 10.1139/cjc-79-11-1522

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Homo-coupling polycondensation of aromatic compounds bearing two (trimethylsilyl)ethynyl groups mediated by copper(I) chloride in DMF gives conjugated poly(arylenebutadiynylene)s in up to 94% yield with molecular weight of 4000-8900 (M-w/M-n = 1.78-2.09).

DOI： 10.1246/cl.2001.950

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

A combination of CP2TiCl2-2EtMgBr was found to be very effective for the formation of monocyclic titanacyclopentenes in excellent yields. On the other hand, a combination of Cp2TiCl2-2n-BuLi was used for intermolecular coupling of two alkynes to form titanacyclopentadienes in good to excellent yields. A reaction temperature range from -10 to -30 degreesC was critical for the success of the combinations. Reactions of these in situ-prepared titanacycles show interesting similarities to or differences from their zirconacycle analogs. (C) 2001 Published by Elsevier Science BN.

DOI： 10.1016/S0022-328X(01)01072-5

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PtI2(PPh3)(2) reacts with HOSiMe2(C6H4CF3-4) at 60 degreesC in the presence of AgBF4 to give a mixture of trans-PtI(C6H4CF3-4)(PPh3)(2) (1) and [Pt-2(mu -I)(2)(PPh3)(4)](BF4)(2) (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or NMR spectroscopy. The P-31{H-1}-NMR study of the reaction of AgBF4 with PtI2(PPh3)(2) in acetone-d(6) revealed the formation of trans-[PtI(PPh3)(2)(acetone)]BF4 (3) although isolation of the cationic complex was not feasible due to its facile conversion to 2. Addition of HOSiMe2(C6H4CF3-4) and Ag2O to a toluene Solution of trans-PtI(Ph)(PPh3)(2) causes replacement of the iodo ligand with the siloxo group to afford trans-[Pt(Ph) {OSiMe2(C6H4CF3-4)} (PPh3)(4)] (4). Crystallographic results of 4 show the coordination of the phenyl, siloxo, and PPh3 ligands to the square-planar Pt center with a large Pt-O-Si angle. Complex 4 does not decompose below 60 degreesC in a toluene solution, but reacts with CH2Cl2 and CHCl3 at room temperature to form trans-Pt-Cl(Ph)(PPh3)(2) (5). (C) 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-328X(01)00796-3

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2-Phenyl-1-methylenecyclopropane and 2,2-diphenyl-1-methylenecyclopropane react with MH(CO)(PPh3)(3) (M = Rh, Ir) to produce 1,3-dienes or the intermediate Rh and Ir complexes having a 3-butenyl ligand, depending on the conditions. The structures and chemical properties of the obtained complexes suggest plausible pathways for the ring-opening isomerization of the methylenecyclopropanes to the corresponding dienes.

DOI： 10.1021/om010081n

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The palladium(O)-catalyzed polycondensation of bis-trimethylsilylethynylated compounds with diiodoarenes to give the polymers bearing arylene-ethynylene moieties is carried out by the use of silver(I) oxide as an activator. Polycondensation of bifunctional terminal alkynes and aryl halides is also accomplished by the palladium-catalyzed cross coupling in the presence of tetrabutylammonium hydroxide (TBAOH), tetrabutylammonium fluoride (TBAF), or silver(I) oxide.

DOI： 10.1246/cl.2001.286

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[PtBr(PEt3)(3)]BF4 (1) reacts with art excess of dimetliyl{4-(trifluoromethyl)phenyl}silanol in the presence of Ag2O and 4 Angstrom molecular sieves at 60 OC to afford trans-Pt(C6H4CF3-4)(2)(PEt3)(2) (2) The reaction without molecular sieves and that with addition of a smalE amount of water give a mixture of 2 and [Pt-2(mu -OH)(2)-(PEt3)(4)](BF4)(2). The organic products of the reaction are composed of ArSiMe2-O-(SiMe2-O)(n)-SiMe2Ar (Ar = C6H4 CF3-4, n = 0, 1, 2) a nd cyclooligodimethylsiloxanes in lesser amounts. The obtained complexes were characterized by NMR spectroscopy and X-ray crystallography.

DOI： 10.1021/om010006c

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The reaction of 1-phenyl-2-trimethylsilylethyne with CuCl at 80-100 degreesC in N,N-dimethylformamide (DMF) or N,N-dimethylimidazolidinone (DMI) yielded the alkynylcopper species[Cu2Cl(C drop CPh)(n)] (1) in 56-63% yields. Heating 1 at 80 degreesC under aerobic conditions gave 1,4-diphenyl-1,3-butadiyne in 82% yield via an oxidative coupling of the phenylethynyl ligands. (C) 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-328X(00)00794-4

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Palladium-catalyzed reaction of aryl and alkenyl halides with terminal alkynes in the presence of silver(I) oxide as an activator furnishes various arylated or alkenylated alkynes in good to excellent yields, The similar coupling reaction is also found to proceed using tetrabutylammonium fluoride (TBAF) or tetrabutylammonium hydroxide (TBAOH) as an activator.

DOI： 10.1021/ol0061586

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Palladium-catalyzed cross-coupling of aryl- or alkenylsilanols, silanediols, and silanetriols with a variety of iodoarenes by the catalysis of palladium(0) and in the presence of silver(I) oxide furnished the coupling products in good to excellent yields. The reactions of silanediols or silanetriols under similar conditions proceeded much faster than those of silanols to afford the corresponding coupling products in excellent yields within shorter reaction periods (5-12 h). The measurement of the X-ras diffraction (XRD) pattern of the silver residue after the reaction revealed that silver(I) oxide was converted to silver(I) iodide.

DOI： 10.1021/jo000679p

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The reaction of dimethyl(phenyl)silanol with butyl acrylate in the presence of a stoichiometric amount of Pd(OAc)(2) or by a combined use of 0.1 molar amount of Pd(OAc)(2) and Cu(OAc)(2)/LiOAc (molar ratio 3/2) gave butyl cinnamate in 76% or 57% yield, respectively. The similar reaction with tributyl(phenyl)tin also proceeded in 77% yield. The organotin compound was shown to react faster than the silanol, although the tin reagent sometimes induced undesirable homo-coupling, while the reaction with silanol did not give such by-product.

DOI： 10.1246/bcsj.73.1409

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DOI： 10.1021/ma9908301

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Home-coupling reactions of an alkenyl- or arylsilane readily occur with a copper(I) salt in an aprotic polar solvent such as N, N-dimethylformamide or dimethyl sulfoxide under an aerobic condition to give the corresponding conjugated dienes or biaryls, respectively. Optimization of a copper salt and a solvent for the home-coupling reaction is discussed. The formation of the organocopper intermediates is evidenced by trapping experiments with iodine and by a conjugate addition to methyl vinyl ketone.

DOI： 10.1246/bcsj.73.985

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Reaction of 1-trimethylsilylalkyne with copper(I) chloride in a polar solvent, DMF, at 60 OC under an aerobic conditions smoothly undergoes home-coupling to give the corresponding symmetrical 1,3-butadiynes in 70-99% yields. In addition, (arylethynyl)trimethylsilanes are found to couple with aryl triflates and chlorides in the presence of Cu(I)/Pd(0) (10 mol %/5 or 10 mol %) cocatalyst system to give the corresponding diarylethynes in 49-99% yields. The cross-coupling reaction is applied to a one-pot synthesis of the corresponding unsymmetrical diarylethynes from (trimethylsilyl)ethyne via sequential Sonogashira-Hagihara and the present cross-coupling reactions using two different aryl triflates. The reactions of (arylethynyl)trimethylsilanes with aryl(chloro)ethynes in the presence of 10 mol % of CuCl also yield the corresponding unsymmetrical 1,3-butadiynes in 43-97% yields.

DOI： 10.1021/jo991686k

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The Mizoroki-Heck type reaction of methyl(phenyl)(3,3,3-trifluoropropyl)silanol (1a) with ethyl acrylate in the presence of Pd(OAc)(2) (10 mol%) and Cu(OAc)(2)/LiOAc gave ethyl cinnamate in 70% yield. The palladium-catalyzed cross-coupling of la with 4-iodomethoxybenzene in the presence of Ag2O also afforded 4-methoxybiphenyl in 51% yield.

DOI： 10.1246/bcsj.73.749

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Hydrosilylation of 1-alkynes catalyzed by RhI(PPh3)(3) gives (E)- and (Z)-alkenylsilanes in a stereodivergent manner by switching the reaction conditions and the order of the addition of the reagents. The reaction is also applied to the synthesis of silicon-containing polymers with (E) and (Z) main-chain structures via polyaddition. (C) 2000 Elsevier Science Ltd All rights reserved.

DOI： 10.1016/S0277-5387(99)00409-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ma9913360

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Unprecedented zirconium(II) complexes bearing tethered olefin-phosphine ligands were synthesized and characterized. The molecular structures of the newly synthesized complexes (eta(5)-1,2-Me2C5H3)(2)Zr(CH2=CHCH2CH2PPh2) (1c) and Cp2Zr(CH2=CHCH2CH2CH2PPh2) (2a) were determined by single-crystal X-ray diffraction methods. The stability and reactivity of the series of complexes Cp2Zr{CH2=CH(CH2)(n)PR2} (n = 2, 3; R = Et, Ph) were examined. The complex 2a showed simultaneously both sufficient stability and high reactivity.

DOI： 10.1021/om990103u

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Language：English   Publisher：AMER CHEMICAL SOC  

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Silanols bearing an asymmetric center on silicon, methyl(2-phenylethenyl) (3,3,3-trifluoropropyl)silanol and methyl(phenyl)(vinyl)silanol are synthesized by alkylative cleavages of cyclic siloxanes with an organolithium. Optical resolution of their enantiomers is performed by HPLC with a chiral stationary phase column. Optical characters of thus separated enantiomers are also examined.

DOI： 10.1246/cl.1999.549

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The reactions of aryl- and alkenylsilanols with organic halides are found to proceed in a catalyst system of 5 mol % of Pd(PPh3)(4) and Ag2O (1 equiv) to give the corresponding coupling products in up to 84% yield.

DOI： 10.1021/ol990614c

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The scandium trifluoromethanesulfonate-catalyzed cleavage of acetate bearing two or three fluorine atoms at a position beta to an acetoxy group proceeds exceptionally rapidly. The high efficiency of the hydrolysis is caused by a chelating effect of scandium with the fluorine atoms and an acetate moiety.

DOI： 10.1246/cl.1999.459

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Reduction of several alpha,beta-unsaturated ketones with dimethylphenylsilane and 10-100 mol% of CuF(PPh3)(3). 2EtOH or CuCl/PPh3/Bu4NF proceeds in a 1,4-selective manner to give the corresponding saturated ketones in up to &gt;99% yield. (C) 1999 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0040-4020(99)00141-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GEORG THIEME VERLAG  

Phenytributyltin is found to react with butyl acrylate in the presence of Pd(OAc)(2) (10 mol%), Cu(OAc)(2) (3 mel), and LiO-Ac (2 mel) in DMF to afford butyl 3-phenylpropenoate in 77% yield. Methyl vinyl ketone, acrolein, acrylonitrile, and styrene are also applicable to this reaction as a substrate.

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DOI： 10.1016/s0040-4039(98)00662-5

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DOI： 10.1246/cl.1998.443

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Language：English   Publisher：Elsevier  

DOI： 10.1016/s0040-4039(98)01750-x

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Language：English   Publisher：The Chemical Society of Japan  

Alkenylsilanols are prepared by the reaction of hexamethyltrisiloxane (D₃) with alkenyllithiums or alternatively by the reaction of cyclic siloxanes substituted by an alkenyl group with organolithiums and transformed to the corresponding cyclopropylsilanols using diiodomethane and diethylzinc. Lithium alkenylsilanolates, primary products of the preparation, also undergo cyclopropanation. As in the case of allylic alcohols, the silanol functionality is found to enhance the rate of cyclopropanation compared with that of alkenyltrialkylsilane or alkoxydialkylsilane. The obtained cyclopropylsilanols are further converted into the corresponding cyclopropanols by the Tamao oxidation.

DOI： 10.1246/bcsj.71.2409

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Reaction of Cp2HfCl2 with R3Al (R = Et, n-Pr, or n-Bu) in hexane selectively produced monoalkylhafnocene complexes, Cp2HfRCl (1), in high yields. Cp2HfMeCl (1a) was prepared by the reaction of oxo-bridged hafnocene complex (Cp2HfCl)2(μ-O) with Me3Al. The treatment of 1 with alkylating reagents such as R′Li or EtMgBr afforded unsymmetrical dialkylhafnocene complexes Cp2HfRR′ (3) in good to excellent yields. The kinetic study of thermolysis of Cp2HfEtR (R = Me, Et, n-Bu, sec-Bu, t-Bu or Ph) suggested that decomposition of Cp2HfEt(sec-Bu) was much faster than the others. Cp2Hf(sec-Bu)2 (2e) can be used as a good precursor of Cp2Hf(II) species. Hafnacyclopent-2-enes (4) were prepared in good yields by the reaction of Cp2HfEt2 (2b) with alkynes. © 1997 Elsevier Science S.A.

DOI： 10.1016/S0022-328X(97)00375-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Reaction of unsymmetrical zirconacyclopentanes with allyl chloride or benzoyl chloride in the presence of copper chloride gave allylated or benzoylated products with high regio- and diastereo-selectivities.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Treatment of Cp2ZrCl2 with 2 equiv of EtMgBr in THF, followed by addition of an internal alkyne and subsequent treatment with CO/I-2 gave alpha,beta-disubstituted cyclopentenone in good to high yields. When a conjugated enyne was used as an alkyne component, alpha-alkenyl cyclopentenone was selectively formed in 80-89% yields. In the case of 4,6-decadiyne, alpha-alkynylcyclopentenone was formed in 88% yield. Bridged alkynes such as 1,4-dihexynytbenzene afforded alpha alpha'-bridged cyclopentenone compounds in good yields. (C) 1997 Elsevier Science Ltd.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Trisubstituted alkenylalkoxyzirconocenes which have been prepared from carbozirconation reactions of internal alkynes via zirconacyclopentenes reacted with aryl or alkenyl iodides in the presence of CuCl and a catalytic amount of Pd(PPh(3))(4) to give coupling products. Copyright (C) 1996 Elsevier Science Ltd

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Language：English   Publisher：The Chemical Society of Japan  

Alkynylsilanes reacted with aryl or alkenyl triflates in the presence of 5 mol% of Pd(PPh₃)₄ and 10 mol% of CuCl in DMF to give the corresponding cross-coupling, namely "sila"-Sonogashira-Hagihara coupling, products in good to excellent yields. The present reaction is highly effective for one-pot synthesis of unsymmetrical diarylacetylenes.

DOI： 10.1246/cl.1997.1233

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Other Link： http://orcid.org/0000-0002-1163-264X

DOI： 10.1039/a701898c

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Other Link： http://orcid.org/0000-0002-1163-264X

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Other Link： http://orcid.org/0000-0002-1163-264X

Language：English   Publisher：RSC Publishing  

DOI： 10.1039/a706032g

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Other Link： http://orcid.org/0000-0002-1163-264X

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

When aromatic halides were treated with alkylmagnesium reagents (which have beta-hydrogens) and a catalytic amount of zirconocene dichloride, dehalogenation proceeded smoothly in high yields. The stoichiometric dehalogenation using dialkylzirconocenes also proceeded with high selectivities.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA LAUSANNE  

Selective monofunctionalization was investigated for symmetrical zirconacyclopentanes or symmetrical dialkylzirconocenes. Reaction of zirconacyclopentanes, which were prepared by intermolecular coupling of two alkenes, or intramolecular cyclization of dienes, trienes or tetraenes on zirconium, with PPh(2)Cl or SnR(3)Cl (R = Me, Ph) gave monofunctionalized products in good to high yields with high selectivities. Even in the presence of 2 equiv, of PPh(2)Cl or SnR(3)Cl, only one Zr-carbon bond reacted. Treatment of zirconacycropentanes with methanol yielded monoprotonated complexes. Subsequent addition of halogen such as Br-2 and I-2 to these monoprotonated complexes gave highly selective monohalogenated products. Similar monoprotonation reactions proceeded for dialkylzirconocene or -hafnocene complexes. Reaction of Cp(2)MR(2) (M = Zr or Hf, R = alkyl or aryl) with alcohols afforded alkylalkoxyzirconocene or -hafnocene complexes, Cp(2)MR(OR') (M = Zr or Hf, R' = alkyl or aryl) in high yields with high selectivities. High selectivity of monofunctionalization using PPh(2)Cl, SnR(3)Cl or alcohols can be attributed to the different reactivities between monoalkylzirconocenes which are monofunctionalized products and zirconacyclopentanes or dialkylzirconocenes.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Practical method for preparation of Cp(2)HfRCl and Cp(2)HfRR' has been investigated. Mono(alkyl)hafnocene chloride complexes were selectively prepared by the following methods; (i) a reaction of Cp(2)HfR(OMe) with MeCOCl and (ii) a reaction of Cp(2)HfCl(2) with an excess of R(3)Al. Treatment of Cp(2)HfRCl with R'Al-3 led to an alkyl exchange reaction to form Cp(2)HfR'Cl. Mono(alkyl)hafnocene complexes prepared by (ii) reacted with one equiv of R'Li to give Cp(2)HfRR' (R not equal R') with a high selectivity.

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/ja00149a040

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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