Photocatalytic Methylation of Nonactivated sp(3) and sp(2) C-H Bonds Using Methanol on GaN

Although the development of C-H functionalization methods has enlightened many reactivities in chemistry, the direct functionalization of unactivated C-H bonds, which are particularly common in petroleum compounds, is still faced with great difficulty. Herein, we describe a photocatalytic approach that allows direct methylation of unactivated sp(3) and sp(2) C-H bonds using methanol as the methylation reagent, with gallium nitride as a powerful yet robust catalyst. Mechanistic studies suggested that the methanol is dehydrated into methyl carbene intermediate via a bimolecular mechanism.