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Visible-Light-Induced Alkoxyl Radicals Enable ?-C(sp3)-H Bond Allylation.

ABSTRACT: The alkoxyl radical is an essential reactive intermediate in mechanistic studies and organic synthesis with hydrogen atom transfer (HAT) reactivity. However, compared with intramolecular 1,5-HAT or intermolecular HAT of alkoxyl radicals, the intramolecular 1,2-HAT reactivity has been limited to theoretical studies and rarely synthetically utilized. Here we report the first selective 1,2-HAT of alkoxyl radicals for ?-C(sp3)-H bond allylation of ?-carbonyl, ?-cyano, ?-trifluoromethyl, and benzylic N-alkoxylphthalimides. The mechanistic probing experiments, electron paramagnetic resonance (EPR) studies, and density functional theory (DFT) calculations confirmed the 1,2-HAT reactivity of alkoxyl radicals, and the use of protic solvents lowered the activation energy by up to 10.4 kcal/mol to facilitate the ?-C(sp3)-H allylation reaction.

SUBMITTER: Zhang J

PROVIDER: S-EPMC6941871 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Visible-Light-Induced Alkoxyl Radicals Enable α-C(sp3)-H Bond Allylation.

Zhang Jing J Liu Dan D Liu Song S Ge Yuanyuan Y Lan Yu Y Chen Yiyun Y

iScience 20191204 1

The alkoxyl radical is an essential reactive intermediate in mechanistic studies and organic synthesis with hydrogen atom transfer (HAT) reactivity. However, compared with intramolecular 1,5-HAT or intermolecular HAT of alkoxyl radicals, the intramolecular 1,2-HAT reactivity has been limited to theoretical studies and rarely synthetically utilized. Here we report the first selective 1,2-HAT of alkoxyl radicals for α-C(sp3)-H bond allylation of α-carbonyl, α-cyano, α-trifluoromethyl, a ...[more]

PMID: 31884167

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