Photocatalyzed Site-Selective C(sp3)-H Functionalization of Alkylpyridines at Non-Benzylic Positions

Takahide Fukuyama; Tomohiro Nishikawa; Keiichi Yamada; Davide Ravelli; Maurizio Fagnoni; Ilhyong Ryu

doi:10.1021/acs.orglett.7b03339

Photocatalyzed Site-Selective C(sp³)-H Functionalization of Alkylpyridines at Non-Benzylic Positions

Takahide Fukuyama, Tomohiro Nishikawa, Keiichi Yamada, Davide Ravelli, Maurizio Fagnoni, Ilhyong Ryu^*

^*Corresponding author for this work

Department of Applied Chemistry

Research output: Contribution to journal › Article › peer-review

15 Scopus citations

Abstract

Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp³)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the S_H2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.

Original language	English
Pages (from-to)	6436-6439
Number of pages	4
Journal	Organic Letters
Volume	19
Issue number	23
DOIs	https://doi.org/10.1021/acs.orglett.7b03339
State	Published - 1 Dec 2017

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title = "Photocatalyzed Site-Selective C(sp3)-H Functionalization of Alkylpyridines at Non-Benzylic Positions",

abstract = "Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp3)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the SH2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.",

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T1 - Photocatalyzed Site-Selective C(sp3)-H Functionalization of Alkylpyridines at Non-Benzylic Positions

AU - Fukuyama, Takahide

AU - Nishikawa, Tomohiro

AU - Yamada, Keiichi

AU - Ravelli, Davide

AU - Fagnoni, Maurizio

AU - Ryu, Ilhyong

PY - 2017/12/1

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N2 - Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp3)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the SH2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.

AB - Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp3)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the SH2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.

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