Metal-free synthesis of nitriles from aldehydes and ammonium by visible-light photocatalysis

A green method for synthesis of nitriles from aldehydes and ammonium salts under air is developed under extremely mild conditions, i.e., 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as a photocatalyst, 2,2,6,6-tetrametylpiperidine-1-oxyl (TEMPO) as a cocatalyst, and oxygen (ambient air) as the terminal oxidant, visible light irradiation of substrate solutions, producing the desired nitriles with excellent yields. The reaction involves two distinct transformations, imine formation between an aldehyde and an ammonium salt and photocatalytic oxidation of the formed imine by air to a nitrile.

Automated summary

A green synthesis method has been developed for the formation of nitriles from aldehydes and ammonium salts using visible light irradiation. The reaction involves imine formation and photocatalytic oxidation of the imine to a nitrile, under extremely mild conditions, resulting in excellent yields.