A New Ring Expansion Reaction of 1-Acyl-2-vinylpiperidine and 1-Acyl-2-Vinylpiperazine via Aza-Claisen Rearrangement of Amide Enolate

Abstract
A new ring expansion reaction of 1-acyl-2-vinylpiperidines and 1-acyl -2-vinylpiperazines has been achieved. Amide enolate induced aza-Claisen rearrangements of 1-acyl-2-azacycles provide the corresponding lactams possessing various substituents at α-position of carbonyl in good yields.