研究者詳細 - 菅　誠治

論文 - 菅　誠治

分割表示 154 件中 81 - 100 件目／全件表示 >>

Electro-reductive cyclization of aryl halides promoted by fluorene derivatives

Koichi Mitsudo, Yumiko Nakagawa, Jun-ichi Mizukawa, Hideo Tanaka, Ryoichi Akaba, Takahiro Okada, Seiji Suga

ELECTROCHIMICA ACTA 82 444 - 449 2012年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

In the presence of fluorene derivatives, the electro-reduction of aryl chlorides, bromides, and iodides bearing an ethylene moiety proceeded smoothly to afford the corresponding cyclized products. Noteworthy is that aryl chlorides, which have more negative reduction potential than aryl bromides and iodides, exhibited high reactivity in the reaction, and the corresponding five-membered and six-membered cyclized products were obtained in good to high yields. Mechanistic study suggests that the electro-reduction of fluorene derivatives was essential for the reactions, indicating that they work as a mediator. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2012.03.130

Kinetic Resolution of Secondary Alcohols by the Combination of a Chiral Bronsted Acid, DABCO, and Acetyl Chloride

Hiroki Mandai, Kyouta Murota, Koichi Mitsudo, Seiji Suga

ORGANIC LETTERS 14 ( 13 ) 3486 - 3489 2012年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

An efficient and simple protocol for the kinetic resolution of secondary alcohols is presented. The new system is based on a combination of chiral Bronsted acid, DABCO, and acetyl chloride and gives various enantioenriched alcohols with selectivity factors up to 105.

DOI： 10.1021/ol301373x

STUDIES ON THE PETASIS REACTION OF 2-PYRIDINECARBALDEHYDE DERIVATIVES AND ITS PRODUCTS

Hiroki Mandai, Kyouta Murota, Seiji Suga

HETEROCYCLES 85 ( 7 ) 1655 - + 2012年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

The Petasis reaction of various 2-pyridinecarbaldehydes with secondary amines and boronic acids in refluxed acetonitrile proceeded to afford desired products up to 96% yield. The reaction proceeded under mild conditions to afford wide range of amines adjacent to heteroaromatic rings. Interestingly, the aldehyde possessing a nucleophilic moiety, 4-(dimethylamino)-2-pyridinecarbaldehyde, with (S)-(-)-N-methyl-1-phenylethylamine and 2 equivalent of trans-2-phenylvinylboronic acid afforded unexpected product, (E)-N-benzyl-3-phenyl-1-(pyridin-2-yl)prop-2-en-1-amine, in high yield. This product might be formed through the direct alkylation of aldehyde by trans-2-phenylvinylboronic acid, followed by anion/enolate isomerization. Derivatization of the Petasis products were also employed and 2-alkyl substituted pyridine derivatives can be obtained through deamination of the Petasis products under the simple hydrogenation conditions.

DOI： 10.3987/COM-12-12500

Synthesis of Nitrogen-Bridged Terthiophenes by Tandem Buchwald-Hartwig Coupling and Their Properties

Koichi Mitsudo, Shuichi Shimohara, Jun Mizoguchi, Hiroki Mandai, Seiji Suga

ORGANIC LETTERS 14 ( 11 ) 2702 - 2705 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

The first synthesis of nitrogen-bridged terthiophenes (NBTTs) has been achieved by a tandem Buchwald-Hartwig coupling of 3,3',3 '', 4'-tetrabromo-2,2':5',2 ''-terthiophene. Several NBTT derivatives bearing aryl or alkyl moieties on the N-atoms could be synthesized. Their fundamental electrochemical characteristics and HOMO-LUMO levels were found to be influenced by the substituents on the N-atoms.

DOI： 10.1021/ol300887t

Electrophilic substitution reactions using an electrogenerated ArS(ArSSAr)(+) cation pool as an ArS+ equivalent

Kouichi Matsumoto, Yuki Kozuki, Yosuke Ashikari, Seiji Suga, Shigenori Kashimura, Jun-ichi Yoshida

TETRAHEDRON LETTERS 53 ( 15 ) 1916 - 1919 2012年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Arylbis(arylthio)sulfonium ions (ArS(ArSSAr)(+)), which were generated and accumulated by the low-temperature electrolysis of diary! disulfide (ArSSAr), were found to serve as ArS+ equivalent in electrophilic substitution reactions of aromatic compounds, enolizable ketones, enol acetates, ketene silyl acetals and allylsilanes to give the corresponding arylthiolated products. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2012.01.131

Site-selective sequential coupling reactions controlled by "Electrochemical Reaction Site Switching": a straightforward approach to 1,4-bis(diaryl)buta-1,3-diynes

Koichi Mitsudo, Natsuyo Kamimoto, Hiroki Murakami, Hiroki Mandai, Atsushi Wakamiya, Yasujiro Murata, Seiji Suga

ORGANIC & BIOMOLECULAR CHEMISTRY 10 ( 48 ) 9562 - 9569 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Site-selective sequential coupling reactions directed toward bis(diaryl)butadiynes are described. The reaction site could be controlled completely by the on/off application of electricity. The electro-oxidative homo-coupling of terminal alkynes (electricity ON) and the subsequent Suzuki-Miyaura coupling (electricity OFF) afforded bis(diaryl) butadiynes in high yields. The obtained 1,4-bis(diaryl)butadiynes could be converted to a 2,5-bis(diaryl)thiophene derivative, which exhibited blue fluorescence.

DOI： 10.1039/c2ob26567b

Studies on the Synthesis of DMAP Derivatives by Diastereoselective Ugi Reactions

Hiroki Mandai, Shunsuke Irie, Koichi Mitsudo, Seiji Suga

MOLECULES 16 ( 10 ) 8815 - 8832 2011年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI

Diastereoselective Ugi reactions of DMAP-based aldehydes with alpha-amino acids and tert-butyl isocyanide were examined. The reactions of 4-(dimethylamino)-2-pyridine-carboxaldehyde with various alpha-amino acids afforded 2-substituted DMAP derivatives with low diastereoselectivity. On the contrary, reactions with 4-(dimethylamino)-3-pyridine-carboxaldehyde delivered 3-substituted DMAP derivatives with moderate to high diastereoselectivity. The combination of alpha-amino acid and DMAP-based aldehyde is thus important to achieve high diastereoselectivity. Kinetic resolution of a secondary alcohol using a chiral DMAP derivative obtained through these reactions was also examined.

DOI： 10.3390/molecules16108815

TRPA1 underlies a sensing mechanism for O-2

Nobuaki Takahashi, Tomoyuki Kuwaki, Shigeki Kiyonaka, Tomohiro Numata, Daisuke Kozai, Yusuke Mizuno, Shinichiro Yamamoto, Shinji Naito, Ellen Knevels, Peter Carmeliet, Toru Oga, Shuji Kaneko, Seiji Suga, Toshiki Nokami, Jun-ichi Yoshida, Yasuo Mori

NATURE CHEMICAL BIOLOGY 7 ( 10 ) 701 - 711 2011年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

Oxygen (O-2) is a prerequisite for cellular respiration in aerobic organisms but also elicits toxicity. To understand how animals cope with the ambivalent physiological nature of O-2, it is critical to elucidate the molecular mechanisms responsible for O-2 sensing. Here our systematic evaluation of transient receptor potential (TRP) cation channels using reactive disulfides with different redox potentials reveals the capability of TRPA1 to sense O-2. O-2 sensing is based upon disparate processes: whereas prolyl hydroxylases (PHDs) exert O-2-dependent inhibition on TRPA1 activity in normoxia, direct O-2 action overrides the inhibition via the prominent sensitivity of TRPA1 to cysteine-mediated oxidation in hyperoxia. Unexpectedly, TRPA1 is activated through relief from the same PHD-mediated inhibition in hypoxia. In mice, disruption of the Trpa1 gene abolishes hyperoxia- and hypoxia-induced cationic currents in vagal and sensory neurons and thereby impedes enhancement of in vivo vagal discharges induced by hyperoxia and hypoxia. The results suggest a new O-2-sensing mechanism mediated by TRPA1.

DOI： 10.1038/NCHEMBIO.640

Kumada-Tamao-Corriu Coupling Using N-Heterocyclic Carbene Ligands Bearing Pyridyl and Ethylenedioxyl Moieties

Koichi Mitsudo, Yuta Doi, Syunsuke Sakamoto, Hiroki Murakami, Hiroki Mandai, Seiji Suga

CHEMISTRY LETTERS 40 ( 9 ) 936 - 938 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

Carbene ligands bearing a pyridyl group and an ethylenedioxyl moiety were developed, and utilized as efficient ligands for the nickel-catalyzed Kumada-Tamao-Corriu coupling. A wide variety of aryl chlorides could be used for the cross-coupling reaction with aryl Grignard reagents to afford the corresponding products in high yields in short time.

DOI： 10.1246/cl.2011.936

Indirect Cation-Flow Method: Flash Generation of Alkoxycarbenium Ions and Studies on the Stability of Glycosyl Cations

Kodai Saito, Koji Ueoka, Kouichi Matsumoto, Seiji Suga, Toshiki Nokami, Jun-ichi Yoshida

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50 ( 22 ) 5153 - 5156 2011年

Organic reactions mediated by electrochemically generated ArS+

Kouichi Matsumoto, Seiji Suga, Jun-ichi Yoshida

ORGANIC & BIOMOLECULAR CHEMISTRY 9 ( 8 ) 2586 - 2596 2011年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Low-temperature electrochemical oxidation of ArSSAr was carried out to generate a pool of "ArS+". Spectroscopic studies (H-1 NMR and CSI-MS) of the resulting solution revealed the accumulation of ArS(ArSSAr)(+). The resulting "ArS+" pool reacted with alkenes and alkynes to give diarylthio-substituted products. The "ArS+" pool rapidly reacted with thioacetals to give the corresponding alkoxycarbenium ion pools, which reacted with various carbon nucleophiles (indirect cation pool method). The reaction of the alkoxycarbenium ion pools with stilbene derivatives in the presence of ArSSAr gave thiochroman derivatives. In addition to such stoichiometric reactions, a catalytic amount of "ArS+" serves as an initiator and a chain carrier of some cationic chain reactions involving intramolecular carbon-carbon bond formation. In situ generation of "ArS+" by electrochemical oxidation of ArSSAr with a catalytic amount of electricity in the presence of a substrate is also effective for such cationic chain reactions.

DOI： 10.1039/c0ob01070g

Cationic Three-component Coupling Involving an Optically Active Enamine Derivative. From Time Integration to Space Integration of Reactions

Seiji Suga, Daisuke Yamada, Jun-ichi Yoshida

CHEMISTRY LETTERS 39 ( 4 ) 404 - 406 2010年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

Three-component coupling of an N-acyliminium cation pool, an optically active 2-t-butyloxazole derivative, and a carbon nucleophile such as allyltrimethylsilane was effectively achieved by a rapid one-pot method at -78 degrees C and a flow microreactor method at 0 degrees C.

DOI： 10.1246/cl.2010.404

Addition of ArSSAr to carbon-carbon multiple bonds using electrochemistry

Shunsuke Fujie, Kouichi Matsumoto, Seiji Suga, Toshiki Nokami, Jun-ichi Yoshida

TETRAHEDRON 66 ( 15 ) 2823 - 2829 2010年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

ArS(ArSSAr)(+) (arylbis(arylthio)sulfonium ions), which were generated and accumulated by the electro-chemical oxidation of diaryl disulfides (ArSSAr) in CH(2)Cl(2) at -78 degrees C, reacted with alkenes to give the corresponding diarylthio-substituted compounds in a stereospecific manner in good yields, when the reaction was quenched with a soft nucleophile, such as allylsilanes, ketene silyl acetals, and triethylamine. A mechanism involving the initial formation of an episulfonium ion followed by ring-opening by the attack of ArSSAr has been suggested. The reactions of ArS(ArSSAr)(+) with alkynes also took place to give 1,2-diorganothio-substitued alkenes stereoselectively under similar conditions. (C) 2010 Published by Elsevier Ltd.

DOI： 10.1016/j.tet.2010.02.049

Electrochemical generation of silver acetylides from terminal alkynes with a Ag anode and integration into sequential Pd-catalysed coupling with arylboronic acids

Koichi Mitsudo, Takuya Shiraga, Jun-ichi Mizukawa, Seiji Suga, Hideo Tanaka

CHEMICAL COMMUNICATIONS 46 ( 48 ) 9256 - 9258 2010年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

An electro-oxidative method for generating silver acetylides from acetylenes with a Ag anode was developed. The reaction could be integrated into a Pd-catalysed electrochemical Sonogashira-type reaction. In the presence of the catalytic amount of Pd(OAc)(2) and 4-BzO-TEMPO, electro-generated silver acetylides reacted immediately with arylboronic acids to afford the corresponding coupling adducts in high yields.

DOI： 10.1039/c0cc02633f

Direct and indirect electrochemical generation of alkoxycarbenium ion pools from thioacetals

Kouichi Matsumoto, Koji Ueoka, Shinkiti Suzuki, Seiji Suga, Jun ichi Yoshida

Tetrahedron 65 ( 52 ) 10901 - 10907 2009年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Thioacetals were found to be effective precursors to generate and accumulate alkoxycarbenium ions based on direct and indirect cation pool methods. Alkoxycarbenium ions thus generated reacted with carbon nucleophiles such as allylsilanes and enol silyl ethers to give C-C bond formation products in good yields. © 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tet.2009.09.020

Thiofluorination of Carbon-Carbon Multiple Bonds Using Electrochemically Generated ArS(ArSSAr)+BF4-

Shunsuke Fujie, Kouichi Matsumoto, Seiji Suga, Jun-ichi Yoshida

CHEMISTRY LETTERS 38 ( 12 ) 1186 - 1187 2009年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The reaction of alkenes and alkynes with ArS(ArSSAr)(+)BF4-, which was generated and accumulated by the low-temperature anodic oxidation of ArSSAr in Bu4NBF4/CH2Cl2, led to the addition of an ArS group and fluoride across the carbon-carbon multiple bond to give thio-fluorinated compounds in good yields.

DOI： 10.1246/cl.2009.1186

Generation of diarylcarbenium ion poolsviaelectrochemical C-H bond dissociation

Masayuki Okajima, Kazuya Soga, Takashi Watanabe, Kimitada Terao, Toshiki Nokami, Seiji Suga, Jun Ichi Yoshida

Bulletin of the Chemical Society of Japan 82 ( 5 ) 594 - 599 2009年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The "cation pools" of diarylcarbenium ions have been generated by the low-temperature electrochemical oxidation of diphenylmethane derivatives. In addition to diphenylmethanes having various substituents, 9,10-dihydroanthracene, dibenzosuberane, and xanthenes, which are annulated derivatives of diphenylmethane were also found to serve as a precursor of cation pools. The generation of the diarylcarbenium ion was confirmed by low-temperature NMR analysis and cold-spray mass analysis. Reactivity was also investigated by reactions with various carbon nucleophiles such as allyltrimethylsilane, 1,3,5-trimethylbenzene, and anisole. © 2009 The Chemical Society of Japan.

DOI： 10.1246/bcsj.82.594

Addition of ArSSAr to dienes via intramolecular C-C bond formation initiated by a catalytic amount of ArS⁺

Kouichi Matsumoto, Shunsuke Fujie, Seiji Suga, Toshiki Nokami, Jun Ichi Yoshida

Chemical Communications ( 36 ) 5448 - 5450 2009年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

A catalytic amount of electrochemically generated "ArS +" ("ArS+" = ArS(ArSSAr)+) initiates a cation chain reaction of dienes that involves the addition of ArSSAr associated with stereoselective intramolecular carbon-carbon bond formation, and the direct (in-cell) electrolysis of a mixture of a diene and ArSSAr with a catalytic amount of electricity also effectively initiates the reaction. © The Royal Society of Chemistry 2009.

DOI： 10.1039/b910821a

Practical electrochemical iodination of aromatic compounds

Kazuhide Kataoka, Yuji Hagiwara, Koji Midorikawa, Seiji Suga, Jun Ichi Yoshida

Organic Process Research and Development 12 ( 6 ) 1130 - 1136 2008年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A practical method for electrochemical iodination of aromatic compounds was developed. The method involves the generation of I+ by electrochemical oxidation of I2 in CH3CN using H 2SO4 as supporting electrolyte followed by the reaction with aromatic compounds. The para/ortho selectivity for the reaction of mono-substituted benzenes was significantly improved using dimethoxyethane as cosolvent in the second step. The reaction with highly reactive aromatic compounds led to the formation of significant amounts of diiodo compounds in a macrobatch reactor. This problem was solved by fast 1:1 mixing of I+ with an aromatic compound using a microflow system consisting of a T-shaped micromixer and a microtube reactor. © 2008 American Chemical Society.

DOI： 10.1021/op800155m

Synthesis of thiochromans based on indirect cation pool method

Kouichi Matsumoto, Koji Ueoka, Shunsuke Fujie, Seiji Suga, Jun ichi Yoshida

Heterocycles 76 ( 2 ) 1103 - 1119 2008年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

A method for the synthesis of thiochromans based on the reactions of stilbenes and alkoxycarbenium ion pools, which were generated and accumulated by the reaction of anodically generated ArS(ArSSAr)+ with thioacetals, has been developed. © 2008 The Japan Institute of Heterocyclic Chemistry All rights reserved.

DOI： 10.3987/COM-08-S(N)64

　前のページ - 次のページ　

1
2
3
4
5
6
7
8