Visible-Light-Induced Acylative Pyridylation of Styrenes

作者：Zhiqin Zhang, Jianwei Wang, Chenfeng Yu, Jiajing Tan, Hongguang Du, Ning Chen · 发表于：Organic Letters · 年份：2024 · DOI：10.1021/acs.orglett.4c01508 · 被引用次数：28 · 研究领域：Radical Photochemical Reactions、Oxidative Organic Chemistry Reactions、Catalytic C–H Functionalization Methods

A visible-light-induced photocatalyst-free acylative pyridylation of styrenes with 4-acyl-1,4-dihydropyridines (DHPs) and 4-cyanopyridines has been described, featuring mild reaction conditions, a broad substrate scope, and good functional group tolerance. The reaction could also be performed under sunlight irradiation albeit with a slightly lower conversion. 4-Acyl-1,4-DHPs serve a dual role, acting as both a photoreductant to reduce the cyanopyridine to its radical anion intermediate and a radical precursor to produce the acyl radical. The mechanism was especially elucidated through the Hammett analysis, with the quadratic linear regression analysis by using radical dual parameters, σ mb and σ jj· . The findings from Hammett analysis further demonstrate that the rate-limiting step of the process is the single electron transfer between 4-acyl-1,4-DHPs and 4-cyanopyridines.