A retro-Mannich mediated transformation of Morita–Baylis–Hillman ketones to saturated imidazo[1,2-a]pyridines

Abstract

Explicit evidence of a retro-Mannich reaction triggered by a vicinal diamine upon its interaction with Morita–Baylis–Hillman ketones was gained by the use of a substrate derived from cyclohex-2-en-1-one. The reaction of such cyclic MBH ketones with ethylene diamine resulted in the formation of novel 5-alkylidene octahydroimidazo[1,2-a]pyridines; a range of substrates, which could also be generated in situ, participated in swift fashion to deliver good yields of the fused hetero-bicyclic products.