Faculty Profiles - ABE Takumi

Papers - ABE Takumi

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First Total Synthesis of Reassigned Echinosulfonic Acid D Reviewed

Takumi Abe, Ren Nakajima, Toshiki Yamashiro, Daisuke Sawada

Journal of Natural Products 85 ( 8 ) 2022.8

Outstanding Reviewers for Organic & Biomolecular Chemistry in 2021

Takumi Abe

Organic & Biomolecular Chemistry 20 ( 28 ) 5499 - 5499 2022.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Organic & Biomolecular Chemistry

<jats:p>We would like to take this opportunity to highlight the Outstanding Reviewers for <jats:italic>Organic & Biomolecular Chemistry</jats:italic> in 2021, as selected by the editorial team for their significant contribution to the journal.</jats:p>

DOI： 10.1039/D2OB90069F

Scopus

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

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

Chemistry - A European Journal 28 ( 37 ) 2022.5

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

Miho Ibara, Takumi Abe, Daisuke Sawada

Organic Letters 2022.3

Synthesis of 2-monosubstituted indolin-3-ones by cine-substitution of 3-azido-2-methoxyindolines Invited Reviewed

Toshiki Yamashiro, Takumi Abe, Daisuke Sawada

Organic Chemistry Frontiers 9 ( 7 ) 1897 - 1903 2022.2

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Royal Society of Chemistry ({RSC})

We have developed an efficient reaction of 3-azido-2-methoxyindolines with <italic>O</italic>-nucleophiles in the presence of a Lewis acid, affording 2-monoacyloxy or alkoxy indolin-3-ones.

DOI： 10.1039/D2QO00048B

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Cis-3-Azido-2-Methoxyindolines as Safe and Stable Precursors to Overcome the Instability of Fleeting 3-Azidoindoles Reviewed International journal

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

Chemical Communications 57 ( 98 ) 13381 - 13384 2021.11

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

Use of 3-azidoindoles in organic synthesis remains difficult task owing to their instabilities. Herein, we report a general and concise approach for tackling this problem by using 3-azidoindole surrogates. The...

DOI： 10.1039/d1cc06033c

PubMed

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Synthesis of α-substituted indolylacetamide using acetonitriles as acetamide enolate equivalents through O-transfer reactions. Reviewed International journal

Takumi Abe, Kenta Noda, Daisuke Sawada

Chemical communications (Cambridge, England) 57 ( 61 ) 7493 - 7496 2021.7

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

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

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

Takumi Abe, Seiya Hirao, Toshiki Yamashiro

CHEMICAL COMMUNICATIONS 56 ( 70 ) 10183 - 10186 2020.9

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

Enamines undergo alpha-indolization with ammonium salts in the presence of Et3N to form alpha-indolylketones. This is the first example of transition metal-, oxidant-, and fluorous solvent-free alpha-indolization of ketones. Key to the success of this convenient protocol was the use ofin situgenerated electrophilic indole species, as well as the use of enamines as a ketone enolate equivalent.

DOI： 10.1039/d0cc04795c

Web of Science

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レセルピンの立体化学表記の訂正

Takumi Abe

ファルマシア 2020.8

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

Takumi Abe

Organic & Biomolecular Chemistry 2020.5

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

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

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

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

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

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

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

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

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

Chemical Communications 2020

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

Takumi Abe

HETEROCYCLES 101 ( 1 ) 2020

Development and Application of Indole-2,3-epoxide Surrogates Reviewed

Abe Takumi, Yamada Koji, Nishi Takahide

Journal of Synthetic Organic Chemistry, Japan 78 ( 6 ) 597 - 607 2020

Authorship：Lead author,　Corresponding author Language：Japanese Publisher：The Society of Synthetic Organic Chemistry, Japan

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

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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

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

Takumi Abe, Seiya Hirao

Organic & Biomolecular Chemistry 18 ( 22 ) 2020

Silver-Mediated Intramolecular Friedel–Crafts-Type Cyclizations of 2-Benzyloxy-3-bromoindolines: Synthesis of Isochromeno[3,4-b] indolines and 3-Arylindoles Reviewed

Toshiki Yamashiro, Koji Yamada, Haruka Yoshida, Yutaro Tomisaka, Takahide Nishi, Takumi Abe

Synlett 30 ( 20 ) 2247 - 2252 2019.11

Authorship：Last author,　Corresponding author Publishing type：Research paper (scientific journal)

© 2019 Georg Thieme Verlag. All rights reserved. We disclose a silver-mediated intramolecular Friedel-Crafts-type cyclization of 2-benzyloxy-3-bromoindolines to afford an untapped family of isochromeno[3,4-b[indolines and 3-arylindoles, in which deformylative arylation of 2-(4-methoxybenzyloxy)-3-bromoindolines is reported for the first time. The isochromeno[3,4-b[indolines can be readily transformed into other heterocyclic moieties.

DOI： 10.1055/s-0039-1690734

Scopus

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Total Synthesis of Fontanesine B and Its Isomer: Their Antiproliferative Activity against Human Colorectal Cancer Cells Reviewed International journal

Takumi Abe

Helvetica Chimica Acta 102 ( 7 ) 2019.6

Total Synthesis of Proposed Structure of Azepinobisindole Alkaloid Rhodozepinone Reviewed

Takumi Abe

HETEROCYCLES 98 ( 6 ) 2019.5

Revisiting Furodiindolines: One-Pot Synthesis of Furodiindolines Using Indole 2,3-Epoxide Surrogates and Their Synthetic Applications Reviewed

Takumi Abe, Sakura Aoyama, Masami Ohmura, Masato Taniguchi, Koji Yamada

Organic Letters 21 ( 9 ) 3367 - 3371 2019.4

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