Green, versatile, and scale-up synthesis of amides by aerobic oxidative amination over Ag2O/P-C3N4 photocatalyst

Abstract

Being extensively applied in various fields of chemistry and chemical industry, the development of a green and versatile method for the synthesis of amides is in line with the demand of sustainable chemistry. Herein, a direct, highly selective, and scale-up (5–20 mmol) method for photocatalytic synthesis of amides through aerobic oxidative amination of alcohols with amines was developed under visible light, room temperature, using air as the oxidant. Benefiting from the adsorption of sodium hemiaminal on catalyst lengthens the CH bond (1.148 Å), this novel process is feasible for a broad range of functionlized amides (69 examples), especially those for drug manufacture (e.g., moclobemide and pipobroman). Imines was almost prevented with excellent amide selectivity up to 99 % could be ascribed to the low energy barrier for hemiaminal dehydrogenation while that for dehydration is high (2.13 eV). This green and efficient protocol represents an ideal alternative to the currently known methods.