Copper catalysis: ligand-controlled selective N-methylation or N-formylation of amines with CO2 and phenylsilane

Abstract

Cupric subcarbonate (Cu₂(OH)₂CO₃) was found to be effective for the reductive functionalization of CO₂ to produce formamides and methylamines with phenylsilane as reductant. Interestingly, N-formylation and N-methylation were switched on/off by subtly choosing the ligand: DPPB (1,4-bis(diphenylphosphino)butane) promoted N-methylation whereas Ph₂CyP (diphenylcyclohexylphosphine) favored for N-formylation.