Photoredox Catalytic Phosphine-Mediated Deoxygenative Hydroacylation of Azobenzenes with Carboxylic Acids.

The convenient and precise preparation of N , N '-diarylhydrazides, especially from readily available raw materials, remains highly challenging. Here, a photoredox catalytic phosphine-mediated deoxygenative hydroacylation of azobenzenes with abundant and readily available carboxylic acids has been developed. With Ir[dF(CF 3 )ppy] 2 (dtbbpy)PF 6 as the photocatalyst, the reactions proceeded smoothly in the presence of PPh 3 under visible light irradiation, delivering various N , N '-diarylhydrazides in up to 92% yields. Mechanistic studies revealed that the reaction proceeds via photoredox catalysis and phosphoranyl-radical-mediated C-O bond cleavage of carboxylic acids.