研究者詳細 - 阿部　匠

論文 - 阿部　匠

分割表示 95 件中 21 - 40 件目／全件表示 >>

First Total Synthesis of Reassigned Echinosulfonic Acid D 査読

Takumi Abe, Ren Nakajima, Toshiki Yamashiro, Daisuke Sawada

Journal of Natural Products 85 ( 8 ) 2022年8月

Outstanding Reviewers for Organic & Biomolecular Chemistry in 2021

Takumi Abe

Organic & Biomolecular Chemistry 20 ( 28 ) 5499 - 5499 2022年7月

Indole Editing Enabled by HFIP-Mediated Ring-Switch Reactions of 3-Amino-2-Hydroxyindolines 査読

Abe, T., Yamashiro, T., Shimizu, K., Sawada, D.

Chemistry - A European Journal 28 ( 37 ) 2022年5月

Chemo- and Site-Selective Replacement of N-Terminal Carbamates in Peptides 査読

2022年3月

Synthesis of 2-monosubstituted indolin-3-ones by cine-substitution of 3-azido-2-methoxyindolines 招待査読

Toshiki Yamashiro, Takumi Abe, Daisuke Sawada

Organic Chemistry Frontiers 9 ( 7 ) 1897 - 1903 2022年2月

Cis-3-Azido-2-Methoxyindolines as Safe and Stable Precursors to Overcome the Instability of Fleeting 3-Azidoindoles 査読国際誌

Toshiki Yamashiro, Takumi Abe, Masaru Tanioka, Shinichiro Kamino, Daisuke Sawada

Chemical Communications 57 ( 98 ) 13381 - 13384 2021年11月

Synthesis of α-substituted indolylacetamide using acetonitriles as acetamide enolate equivalents through O-transfer reactions. 査読国際誌

Takumi Abe, Kenta Noda, Daisuke Sawada

Chemical communications (Cambridge, England) 57 ( 61 ) 7493 - 7496 2021年7月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

We introduce readily available ammonium hemiaminals as O-transfer reagents and commercially available acetonitriles as a primary amide enolate precursor. The combination serves as an amide enolate equivalent, thereby providing one-pot access to α-substituted indolylacetamides. A broad substrate scope and good functional group tolerance as well as gram-scale synthesis make this protocol highly attractive. Mechanistic experiments suggest that the cyano group is trapped by a hydroxy group of hemiaminals en route to the desired primary amides under metal-free conditions.

DOI： 10.1039/d1cc02821a

PubMed

researchmap

A metal-, oxidant-, and fluorous solvent-free synthesis of alpha-indolylketones enabled by an umpolung strategy 査読

Takumi Abe, Seiya Hirao, Toshiki Yamashiro

CHEMICAL COMMUNICATIONS 56 ( 70 ) 10183 - 10186 2020年9月

レセルピンの立体化学表記の訂正

Takumi Abe

ファルマシア 2020年8月

Rapid access to indole-fused bicyclo[2.2.2]octanones by merging umpolung strategy and molecular iodine as a green catalyst 査読

Takumi Abe

Organic & Biomolecular Chemistry 2020年5月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

One-pot synthesis of indole-fused bicyclo[2.2.2]octanones from DiMeOIN and 2-cyclohexen-1-one are accomplished under iodine catalyst. This simple and metal-free conditions provides a practical tool to construct Csp3-rich complex molecules via oxidative...

DOI： 10.1039/d0ob01038c

researchmap

Revisiting 2-Alkoxy-3-bromoindolines: Control C-2 vs. C-3 Elimination for Regioselective Synthesis of Alkoxyindoles. 査読

Takumi Abe, Yuta Kosaka, Takaaki Kawasaki, Yuki Ohata, Toshiki Yamashiro, Koji Yamada

Chemical & pharmaceutical bulletin 68 ( 6 ) 555 - 558 2020年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

The regioselective synthesis of both 2- and 3-alkoxyindoles from a common intermediate, 2-alkoxy-3-bromoindolines (ROBIN), is described. The 2-alkoxyindoles are obtained by a base-promoted regioselective elimination of HBr from ROBIN, whereas the synthesis of 3-alkoxyindoles is achieved by a silver-mediated alkoxylation followed by an acid-promoted elimination of alkoxide. This key elimination features the complete regioselectivity and no need for catalysts, that makes it have potential synthetic applications. Furthermore, this protocol is user friendly because ROBIN is able to be prepared from commercially available indoles and is a bench-stable easy-to-handle crystalline substrate, thus allowing the concise synthesis of a variety of both 2- and 3-alkoxyindoles.

DOI： 10.1248/cpb.c20-00135

PubMed

researchmap

2,3-Dimethoxyindolines: a latent electrophile for SNAr reactions triggered by indium catalysts 査読

Seiya Hirao, Toshiki Yamashiro, Kyouka Kohira, Naoki Mishima, Takumi Abe

Chemical Communications 2020年

A Mild Bischler–Napieralski-Type Cyclization of Trichloromethyl Carbamates for the Synthesis of β-Carbolinones 査読

HETEROCYCLES 101 ( 1 ) 2020年

インドール-2,3-エポキシド代替品の開発と応用査読

阿部匠, 山田康司, 西剛秀

有機合成化学協会誌 78 ( 6 ) 597 - 607 2020年

担当区分：筆頭著者,　責任著者記述言語：日本語出版者・発行元：公益社団法人有機合成化学協会

C3-Nucleophilic substitution of indoles has been limited because the transformation requires an umpolung of the C3 position of indoles. Among the indole derivatives, indole-2,3-epoxides could be potentially be used as C3-electrophilic reagents due to the electrophilic nature of the C2 and C3 positions. However, their use as C3 electrophilic reagents has not been possible so far due to their instability.We describe a novel and bench stable surrogate of indole-2,3-epoxide, 2-hydroxyindoline-3-triethylammonium bromide (HITAB), which was found to be a convenient reagent for formal C3-electrophilic reactions of indoles with nucleophiles. By taking advantage of the nucleophilic character of the oxygen of the 2-hydroxyindoline, interrupted retro-Claisen and interrupted Feist-Bénary reactions with 1,3-dicarbonyl compounds, one-pot formation of furodiindolines from 3-substituted indoles were achieved. Furthermore, we developed a novel cascade reaction of the indole-2,3-epoxide surrogate with γ-carbolines to access multiheterocyclic compounds containing both isotryptamines and pyrimido［1,6-a］indoles. This reaction utilizes the in situ formation of a bulky quaternary ammonium salt via ammonium exchange, which undergoes Hofmann elimination/vinylogous Mannich/retro-Mannich/cyclization cascade sequences. The synthetic potential of the ammonium salts was demonstrated by the short synthesis of cryptolepine, iheyamine A, racemocine B derivative, and neocryptolepine derivative.

DOI： 10.5059/yukigoseikyokaishi.78.597

CiNii Article

CiNii Books

researchmap

Rapid access to indole-fused bicyclo[2.2.2]octanones by merging the umpolung strategy and molecular iodine as a green catalyst

Abe, T., Hirao, S.

Organic and Biomolecular Chemistry 18 ( 22 ) 2020年