Direct use of methanol instead of formaldehyde or paraformaldehyde: Acceptorless dehydrogenative coupling for the synthesis of arylhydrazones catalyzed by a metal–ligand iridium bifunctional catalyst

Abstract

The strategy of the synthesis of arylhydrazones via acceptorless dehydrogenative coupling of arylhydrazines with methanol was proposed and accomplished. In the presence of [Cp*Ir(2,2′-bpyO)(H2O)] (0.5 mol %), a series of desirable products were obtained in high yields. It was found that functional groups in bpy are crucially important for the catalytic activity of iridium complexes. Furthermore, DFT calculations and mechanistic experiments were presented. Notably, this research exhibits the potential of direct use of methanol instead of formaldehyde or paraformaldehyde for organic synthesis.