Oxidative Amidation of Amines in Tandem with Transamidation: A Route to Amides Using Visible-Light Energy

A methodology is reported for preparing amides using amines as an acyl source. The protocol involves the visible-light-promoted oxidative amidation of amines with pyrazole to synthesize -acyl pyrazoles followed by transamidation. By combining photoredox catalysis with oxoammonium cations in the presence of sodium persulfate as a terminal oxidant, the -acyl pyrazoles could be prepared efficiently and effectively using blue LEDs. The transamidation step was performed without the need to purify the -acyl pyrazole intermediate, and a range of amides were generated in good to excellent yields.