Visible light-mediated pyridyl silylation of olefins through hydrogen atom transfer†

A visible light-mediated synthesis protocol for the three-component pyridyl silylation of olefins to access β-pyridyl silicons has been developed. The reaction cascade is initiated by an in situ generated methoxy radical enabled by EDA complexes formed between the electron-deficient N-methoxypyridinium salts and a base. The reaction using hydrosilane as the silicon source to access the silyl radical proceeds well via a hydrogen atom transfer process between a silane Si–H bond and the methoxy radical. This protocol features exogenous photocatalyst-free conditions and high atom economy, thereby providing a powerful synthon for preparing silyl- and pyridyl-containing compounds with excellent functional group compatibility. Therefore, it is expected that this method will find applications in synthetic chemistry and drug discovery.