Pathways of the reaction between N,N-disubstituted propargylic amines and cationic zirconium complexes

Abstract

The reaction of N-tert-alkyl-substituted propargylic amines with trialkylalanes in the presence of 20 mol.% Cp2ZrCl2 was studied. The pattern of the products depended on the nature of substituents at the nitrogen atom. N-tert-Alkyl-N-arylmethyl-substituted propargylic amines when reacted in CH2Cl2 aff ord a mixture of N-tert-alkyl-N-(arylmethyl)alkylamines and N-tertalkyl-N-(arylmethyl)amines at ratios from {2: 3 to {3: 2 in total yield of 70–95%. In hexane, N-tert-alkyl-N-(arylmethyl)amines are produced selectively. N-Alkyl-N-tert-alkyl-substituted propargylic amines similar to N-isoalkyl-substituted ones underwent a Zr-promoted hydride transfer to aff ord (2E)-alkenylamines in good yield (58–69%).