Ligand-assisted nickel catalysis enabling N,N-dialkylation and cyclization of acyl hydrazides using aliphatic alcohols†

Abstract

Herein, we describe a nickel-catalyzed N,N-dilakylation protocol for acyl hydrazides. A series of aliphatic alcohols and diols were successfully dehydrogenated and used for this challenging dialkylation as well as some cyclization reactions. The reaction is chemoselective, as many of the N,N-dialkylated products contain an olefinic motif, with the imine linkage selectively reduced while the olefinic one remains intact. The azo–hydrazo redox couple plays a crucial role in the hydrogenation of imines. The reaction proceeds via a radical pathway and in striking contrast to previous reports that involve metal hydrides.