Catalyst-Free C-H Methylation of Heteroarenes Enabled by Electron
Donor-Acceptor Complex Photoactivation
Abstract
An efficient, additive- and catalyst -free, visible-light-driven radical
C-H methylation of heteroarenes (including quinoxalinones, pyra-zinones,
quinolinones and coumarins) utilizing readily available methylamines as
the methyl source has been developed. The trans-formation possesses the
advantages of operational simplicity, mild reaction conditions and broad
substrate scope. Mechanistic studies disclosed that a photoactive
electron donor-acceptor (EDA) complex between methylamines and
heteroarenes is crucial to this trans-formation.