Reactivity of Propargylic Amines in the Presence of Transition Metals

Abstract

N,N-Dialkyl-substituted propargylic amines undergo various transformations in the presence of transition-metal catalysts: The hydride-transfer reaction in the presence of palladium catalysts to afford the corresponding allenes, the fragment-exchange reaction with amines or acetylenes in the presence of copper(I) catalysts through C(sp)-C(sp³) bond cleavage, and the redox cross-dehydrogenative coupling in the presence of zinc(II) catalysts to afford N-tethered 1,6-enynes. In all the above cases, the generation of iminium intermediates, which would be assisted by a lone pair on the nitrogen atom of the propargylic amines, is essential for further transformations.