Visible Light-Induced Radical Cascade Difluoromethylation/Cyclization of Unactivated Alkenes: Access to
Sheng-Nan Lin1, Yuanyuan Deng1, Hanxun Zhong1
1College of Chemistry and Environment Science, Shangrao Normal University, Shangrao 334001, China.
Abstract:
An efficient and mild protocol for the visible light-induced radical cascade difluoromethylation/cyclization of imidazoles with unactivated alkenes using easily accessible and bench-stable difluoromethyltriphenylphosphonium bromide as the precursor of the -CF2H group has been developed to afford CF2H-substituted polycyclic imidazoles in moderate to good yields. This strategy, along with the construction of Csp3-CF2H/C-C bonds, is distinguished by mild conditions, no requirement of additives, simple operation, and wide substrate scope. In addition, the mechanistic experiments have indicated that the difluoromethyl radical pathway is essential for the methodology.
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