Faculty Profiles - SUGA Seiji

Papers - SUGA Seiji

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Synthesis and Properties of Dithieno-Fused 1,4-Azaborine Derivatives Reviewed

Koichi Mitsudo, Keisuke Shigemori, Hiroki Mandai, Atsushi Wakamiya, Seiji Suga

Organic Letters 20 ( 22 ) 7336 - 7340 2018.11

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

The first synthesis of dithieno[3,2-b:2',3'-e][1,4]azaborinine (DTAB) derivatives has been achieved by Buchwald-Hartwig coupling and subsequent Friedel-Crafts-type C-H borylation. A facile method for further pi-extension of DTAB was also developed via stannylation and subsequent Kosugi-Migita-Stille cross-coupling reaction. The fundamental properties of DTAB derivatives were also investigated.

DOI： 10.1021/acs.orglett.8b03316

Efficient Synthesis and Properties of [1]Benzothieno[3,2-b]thieno[2,3-d]furans and [1]Benzothieno[3,2-b]thieno[2,3-d]thiophenes Reviewed

Yuji Kurimoto, Koichi Mitsudo, Hiroki Mandai, Atsushi Wakamiya, Yasujiro Murata, Hiroki Mori, Yasushi Nishihara, Seiji Suga

ASIAN JOURNAL OF ORGANIC CHEMISTRY 7 ( 8 ) 1635 - 1641 2018.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Efficient syntheses of benzodithienofuran (BDTF; [1]benzothieno[3,2-b]thieno[2,3-d]furan) and benzodithienothiophene (BDTT; [1]benzothieno[3,2-b]thieno[2,3-d]thiophene) were achieved by the combination of an addition-elimination reaction, reduction, and Pd-catalyzed dehydrogenative cyclization. We also achieved the synthesis of pi-ex- tended BDTF and BDTT derivatives through the use of coupling reactions. The detailed physical properties of these compounds were investigated. The newly synthesized BDTFs exhibited strong fluorescence compared with BDTTs. 2,2'-Bis([1]benzothieno[3,2-b]thieno[2,3-d]furan) (BBTTF) exhibited p-type organic field-effect transistor (OFET) properties.

DOI： 10.1002/ajoc.201800270

Cu/Fe/O=PPh3-Catalyzed Etherification for the Synthesis of Aryl 3-Benzo[b]thienyl Ethers Reviewed

Koichi Mitsudo, Takuya Asada, Tomohiro Inada, Yuji Kurimoto, Hiroki Mandai, Seiji Suga

Chemistry Letters 47 ( 8 ) 1044 - 1047 2018.8

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

Cu/Fe-cocatalyzed cross-coupling reactions between 3-bromobenzo[b]thiophene and hydroxyaryls are described herein. The combination of Cu and Fe catalysts is important for the progress of the reactions, and the use of triphenylphosphine oxide as a ligand suppresses the dehalogenation of 3-bromobenzo[b]thiophene, and promptly facilitates the reaction. The obtained aryl benzo[b]thienyl ethers can be converted to pextended thienobenzofuran derivatives via Pd-catalyzed dehydrogenative cyclizations.

DOI： 10.1246/cl.180425

Dynamic Kinetic Resolution of Azlactones by a Chiral N,N-Dimethyl-4-aminopyridine Derivative Containing a 1,1 '-Binaphthyl Unit: Importance of Amide Groups Reviewed

Hiroki Mandai, Kohei Hongo, Takuma Fujiwara, Kazuki Fujii, Koichi Mitsudo, Seiji Suga

Organic Letters 20 ( 16 ) 4811 - 4814 2018.8

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

A dynamic kinetic resolution (DKR) of azlactones in the presence of benzoic acid and a binaphthyl-based N,N-4-dimethylaminopyridine (DMAP) derivative 1i having two amide groups at the 3,3'-positions of a binaphthyl unit is developed. The reaction proceeded smoothly with a wide range of azlactones to provide alpha-amino acid derivatives with good to high enantiomeric ratios (er's). A multigram-scale reaction (2.5 g) for the DKR of azlactone 2d was also demonstrated, and the resulting product was converted to unnatural alpha-amino acid 6d'.

DOI： 10.1021/acs.orglett.8b01960

SYNTHESIS OF OXAZOLINES FROM N-ALLYLAMIDES USING AN ELECTROCHEMICALLY GENERATED ArS(ArSSAr)(+) POOL Reviewed

Yu Miyamoto, Naoya Mitani, Rina Yanagi, Shigenori Kashimura, Seiji Suga, Jun-ichi Yoshida, Kouichi Matsumoto

HETEROCYCLES 96 ( 8 ) 1373 - 1382 2018.8

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

The reaction of N-allylamides with ArS(ArSSAr)(+), which was generated and accumulated by the low-temperature anodic oxidation of ArSSAr, afforded the corresponding ArS-substituted oxazolines in moderate to good yields. In-situ electrochemical oxidation of ArSSAr in the presence of N-allylamides was also applicable. Oxazolines bearing various substituents were successfully synthesized by using the present reactions.

DOI： 10.3987/COM-18-13942

Miniaturization and Combinatorial Approach in Organic Electrochemistry Invited Reviewed

Koichi Mitsudo, Yuji Kurimoto, Kazuki Yoshioka, Seiji Suga

CHEMICAL REVIEWS 118 ( 12 ) 5985 - 5999 2018.6

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

Recent advances in electro-organic chemistry involving miniaturization, integration, and combinatorial chemistry were reviewed. Microelectrode array technology for site-selective electro-organic reactions and addressable libraries provides a direct and unlabeled method for measuring small-molecule-protein interactions. Electrochemical systems using solid-supported bases and acids ("site separation") can realize electrolysis without the addition of supporting electrolytes. Well-designed "bipolar electrodes" have enabled the production of patterned gradient polymer brushes and microfibers. For the display of combinatorial organic electrochemistry, batch and flow electrolysis systems for the optimization and screening of electro-organic reactions as well as the building of chemical libraries for organic compounds are described.

DOI： 10.1021/acs.chemrev.7b00532

Recent topics in enantioselective acyl transfer reactions with dialkylaminopyridine-based nucleophilic catalysts Invited Reviewed

Hiroki Mandai, Kazuki Fujii, Seiji Suga

TETRAHEDRON LETTERS 59 ( 19 ) 1787 - 1803 2018.5

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

This digest focuses on recent topics in intra- and intermolecular enantioselective acyl transfer reactions with dialkylaminopyridine-based catalysts over the past decade (2007-2017). The structures of the catalysts are divided into four categories according to the location of the chiral environment (C2, C3, or C4 position of pyridine, and miscellaneous). The role of the structure in the enantioselective acyl transfer reaction and the reaction mechanism will be discussed briefly. (C) 2018 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2018.03.016

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations Invited Reviewed

Koichi Mitsudo, Junya Yamamoto, Tomoya Akagi, Atsuhiro Yamashita, Masahiro Haisa, Kazuki Yoshioka, Hiroki Mandai, Koji Ueoka, Christian Hempel, Jun-ichi Yoshida, Seiji Suga

BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY 14 1192 - 1202 2018.5

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

In this study, six-membered N-acyliminium ions were generated by the "indirect cation pool" method and reacted with several nucleophiles. These reactions afforded disubstituted piperidine derivatives with high diastereoselectivities and good to excellent yields. The conformations of the obtained N-acyliminium ions were studied by low temperature NMR analyses and DFT calculations and were found to be consistent with the Steven's hypothesis.

DOI： 10.3762/bjoc.14.100

Combinatorial electrochemistry for organic synthesis Invited Reviewed

Koichi Mitsudo, Yuji Kurimoto, Kazuki Yoshioka, Seiji Suga

CURRENT OPINION IN ELECTROCHEMISTRY 8 8 - 13 2018.3

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

In this study, recent advances in electro-organic chemistry based on combinatorial approaches are reviewed. As examples of combinatorial organic electrosynthesis, some batch and flow electrolysis systems for the screening and optimization of electro-organic reactions are described along with the construction of chemical libraries of organic compounds.

DOI： 10.1016/j.coelec.2017.10.026

Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l-1,2-Diols with Chiral Nucleophilic Catalysts Reviewed

Kazuki Fujii, Koichi Mitsudo, Hiroki Mandai, Seiji Suga

ADVANCED SYNTHESIS & CATALYSIS 359 ( 16 ) 2778 - 2788 2017.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

An extremely efficient acylative kinetic resolution of d,l-1,2-diols in the presence of only 0.5 mol% of binaphthyl-based chiral N,N-4-dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert-alcohol unit(s) of the catalyst and the 1,2-diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2-diols with high selectivity factors. The kinetic resolution of d,l-hydrobenzoin and trans-1,2-cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 degrees C); (iii) high substrate concentration (1.0M); and (iv) short reaction time (30 min).

DOI： 10.1002/adsc.201700057

Desymmetrization of meso-1,2-Diols by a Chiral N,N-4-Dimethylaminopyridine Derivative Containing a 1,1'-Binaphthyl Unit: Importance of the Hydroxy Groups Reviewed

Hiroki Mandai, Hiroshi Yasuhara, Kazuki Fujii, Yukihito Shimomura, Koichi Mitsudo, Seiji Suga

JOURNAL OF ORGANIC CHEMISTRY 82 ( 13 ) 6846 - 6856 2017.7

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

We developed an acylative desymmetrization of meso-1,2-diols using a binaphthyl-based N,N-4-dimethylamino-pyridine (DMAP) derivative lh with tert-alcohol substituents. The reaction proceeds with a wide range of acyclic meso-1,2-diols and six-membered-ring meso-1,2-diols to provide a monoacylate selectively with a high enantiomeric ratio (er). Only 0.1 mol % of the catalyst facilitated the reaction within a short reaction time (3 h) to afford enantio-enriched monoacylated products in moderate to good yield. Several control experiments revealed that the tert-alcohol units of catalyst lh play a significant role in achieving high catalytic activity, chemoselectivity of monoacylation, and enantioselectivity.

DOI： 10.1021/acs.joc.7b00992

Development of Efficient and Effective Rate Acceleration Systems in Organocatalysis

Hiroki Mandai, Kazuki Fujii, Seiji Suga

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 75 ( 6 ) 632 - 649 2017.6

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

Catalysts that can promote acyl transfer processes are important for enantioselective synthesis and their development has received significant attention in recent years. Very recently, we developed a method for the synthesis of chiral DMAP derivatives starting from an alpha-amino acid as a chiral source using a diastereoselective Ugi multicomponent reaction, and the protocol allowed us to access a variety of chiral catalysts in a one-step and one-pot manner. Such catalysts could be applied to various enantioselective acyl transfer reactions. In addition, we also reported a conceptually new type of kinetic resolution of secondary alcohols with a chiral phosphoric acid for the first time. Finally, we developed a binaphthyl-based chiral DMAP derivatives utilizing H-bonding interactions for enantioselective intra- and intermolecular acyl transfer reactions with high enantioselectivity. tert-Alcohol units of the catalyst play important roles in the acceleration of the rate of the reaction and achieving high enantioselectivity.

DOI： 10.5059/yukigoseikyokaishi.75.632

Synthesis of 3-Benzo[b]thienyl 3-Thienyl Ether via an Addition-Elimination Reaction and Its Transformation to an Oxygen-Fused Dithiophene Skeleton: Synthesis and Properties of Benzodithienofuran and Its pi-Extended Derivatives Reviewed

Koichi Mitsudo, Yuji Kurimoto, Hiroki Mandai, Seiji Suga

Organic Letters 19 ( 11 ) 2821 - 2824 2017.6

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

The synthesis of 3-benzo[b]thienyl 3-thienyl ether and its dehydrogenative cyclization leading to benzodithienofuran (BDTF; [1]benzothieno[3,2-b]thieno[2,3-d]furan) are described for the first time. Further transformation of BDTF to more p-extended BDTF derivatives and their fundamental physical properties are also studied.

DOI： 10.1021/acs.orglett.7b00969

Rh-Catalyzed Dehydrogenative Cyclization Leading to Benzosilolothiophene Derivatives via Si-H/C-H Bond Cleavage Reviewed

Koichi Mitsudo, Seiichi Tanaka, Ryota Isobuchi, Tomohiro Inada, Hiroki Mandai, Toshinobu Korenaga, Atsushi Wakamiya, Yasujiro Murata, Seiji Suga

Organic Letters 19 ( 10 ) 2564 - 2567 2017.5

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

Straightforward syntheses leading to pi-extended benzosilolothiophene (BST) derivatives by Rh-catalyzed dehydrogenative cyclization reactions have been developed. Electron-deficient ligands were effective for the reactions, and dppe-F-20 gave the best result. This method could be applied to the synthesis of highly pi-extended ladder-type BST derivatives, which exhibited fluorescence.

DOI： 10.1021/acs.orglett.7b00878

Magnetic Attachment of Lipase Immobilized on Bacteriogenic Iron Oxide Inside a Microtube Reactor for the Kinetic Resolution of Secondary Alcohols Reviewed

Kyoko Mandai, Takehiro Fukuda, Yuki Miyazaki, Hideki Hashimoto, Hiroki Mandai, Tadashi Ema, Jun Takada, Seiji Suga

Synlett 28 ( 7 ) 805 - 810 2017.4

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：GEORG THIEME VERLAG KG

A PTFE microtube reactor was constructed with lipase immobilized on magnetized bacteriogenic iron oxide, which was retained inside of the tube by attraction to an external magnet. The reactor was used for the lipase-promoted kinetic resolution of secondary alcohols and gave sufficient catalytic activity, which was maintained during long-term flow over 14 days.

DOI： 10.1055/s-0036-1589953

AN INTRAMOLECULAR NUCLEOPHILE-CATALYZED ALDOL-LACTONIZATION (NCAL) REACTION OF S-ARYL-(E)-6-OXOHEX-2-ENETHIOATE WITH N,N-4-DIMETHYLAMINOPYRIDINE N-OXIDE Reviewed

Hiroki Mandai, Keita Shimowaki, Kohei Hongo, Koichi Mitsudo, Seiji Suga

HETEROCYCLES 94 ( 3 ) 492 - 502 2017.3

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

We have developed an intramolecular nucleophile-catalyzed aldol-lactonization (NCAL) reaction of S-aryl-(E)-6-oxohex-2-enethiolate with N,N-4-dimethylaminopyridine N-oxide (DMAPO) to afford densely functionalized bicyclic beta-lactones in moderate yield. This unique transformation may be explained in terms of nucleophilic substitution of the S-aryl moiety by DMAPO, followed by 1,4-addition of aryl thiolate to generate a zwitterionic enolate and an intramolecular C-C bond-forming reaction (aldol-lactonization).

DOI： 10.3987/COM-16-13614

Facile Synthesis of Naphthothiophenone Derivatives and Anthradithiophenedione via Friedel-Crafts Acylation and Their Fundamental Properties

Koichi Mitsudo, Takashi Murakami, Takuya Shibasaki, Tomohiro Inada, Hiroki Mandai, Hiromi Ota, Seiji Suga

SYNLETT 27 ( 16 ) 2327 - 2332 2016.10

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

Facile synthetic methods for constructing naphthothiophenone and its -extended derivatives were developed. Naphthothiophenone and anthradithiophenedione were synthesized by the S-acylation of thiol to form chlorothioformate and subsequent Friedel-Crafts acylation. A bromination reaction of naphthothiophenone and its application to Suzuki-Miyaura cross-coupling was also carried out. The fundamental physical properties of these compounds were also investigated.

DOI： 10.1055/s-0035-1562470

Kinetic Resolution of Secondary Carbinols by a Chiral N,N-4-Dimethylaminopyridine Derivative Containing a 1,1 '- Binaphthyl Unit: Hydrogen Bonding Affects Catalytic Activity and Enantioselectivity

Kazuki Fujii, Koichi Mitsudo, Hiroki Mandai, Seiji Suga

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 89 ( 9 ) 1081 - 1092 2016.9

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

We developed an acylative kinetic resolution of secondary carbinols using a binaphthyl-based N,N-4-dimethylaminopyridine (DMAP) derivative 1d with tert-alcohol substituents. The reaction proceeded with a wide range of carbinols with moderate to high selectivity (s) (up to s = 79.5). Kinetic studies revealed that catalyst 1d was more catalytically active than the corresponding bis-methyl ether 1d' or DMAP. Hydrogen bonding between tert-alcohols of the catalyst and secondary carbinols was responsible for the enhanced reaction rate and high enantioselectivity.

DOI： 10.1246/bcsj.20160135

Synthetic Terrein Inhibits Progression of Head and Neck Cancer by Suppressing Angiogenin Production

Akane Shibata, Soichiro Ibaragi, Hiroki Mandai, Toki Tsumura, Koji Kishimoto, Tatsuo Okui, Nur Mohammad Monsur Hassan, Tsuyoshi Shimo, Kazuhiro Omori, Guo-Fu Hu, Shogo Takashiba, Seiji Suga, Akira Sasaki

ANTICANCER RESEARCH 36 ( 5 ) 2161 - 2168 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：INT INST ANTICANCER RESEARCH

Background/Aim: Head and neck cancers are the fifth most common cancer type worldwide, affecting more than half a million patients annually. Development of effective therapeutic drugs is, therefore, required for this type of disease. This study assessed the effects of synthetic terrein on head and neck cancer. Materials and Methods: Synthetic terrein was prepared by using the modified Altenhach's procedure. The effect of synthetic terrein on cell proliferation of head and neck cancer cells and HUVECs was assessed. Angiogenin secretion and ribosome biogenesis were examined by ELISA and silver staining of the nucleolar organizer region. A mouse xenograft model was prepared by inoculating mice with suspensions of cells of the human head and neck cancer cell line OSC-19 subcutaneously into the dorsal region of each mouse. Ki-67, CD31 and angiogenin expression in xenografted tumors was examined by immunohistochemistry. Results: Synthetic terrein inhibited the growth of various head and neck cancer cells. In addition, an in vivo experiment revealed that synthetic terrein inhibited a xenograft tumor growth in athymic mice. Immunohistochemical analysis revealed that expression of Ki-67, CD31 and ANG was down-regulated in synthetic terrein-treated tumors, compared to controls. Synthetic terrein suppressed the ANG secretion and ribosome biogenesis in cancer cells, and cell proliferation in vascular endothelial cells. Conclusion: The mechanism underlying the anti-tumor effects of synthetic terrein against head and neck cancer consists of the inhibition of both tumor cell proliferation and angiogenesis via the suppression of ANG production.

Enantioselective acyl transfer catalysis by a combination of common catalytic motifs and electrostatic interactions

Hiroki Mandai, Kazuki Fujii, Hiroshi Yasuhara, Kenko Abe, Koichi Mitsudo, Toshinobu Korenaga, Seiji Suga

NATURE COMMUNICATIONS 7 2016.4

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

Catalysts that can promote acyl transfer processes are important to enantioselective synthesis and their development has received significant attention in recent years. Despite noteworthy advances, discovery of small-molecule catalysts that are robust, efficient, recyclable and promote reactions with high enantioselectivity can be easily and cost-effectively prepared in significant quantities (that is, >10 g) has remained elusive. Here, we demonstrate that by attaching a binaphthyl moiety, appropriately modified to establish H-bonding interactions within the key intermediates in the catalytic cycle, and a 4-aminopyridyl unit, exceptionally efficient organic molecules can be prepared that facilitate enantioselective acyl transfer reactions. As little as 0.5 mol% of a member of the new catalyst class is sufficient to generate acyl-substituted all-carbon quaternary stereogenic centres in quantitative yield and in up to 98: 2 enantiomeric ratio (er) in 5 h. Kinetic resolution or desymmetrization of 1,2-diol can be performed with high efficiency and enantioselectivity as well.

DOI： 10.1038/ncomms11297

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