An Oxidative [3+2+1] Cyclization of Enaminones and N‐Alkenyl‐2‐pyrrolidinone: Access to Polysubstituted 4‐Alkylated 1,4‐dihydropyridines

Abstract An oxidative [3+2+1] cyclization of enaminones and N ‐alkenyl‐2‐pyrrolidinone is described for the synthesis of 4‐alkylated 1,4‐dihydropyridines (1,4‐DHPs). By using terminal olefin as the C4 source of the 1,4‐DHP skeleton, this synthetic strategy provides a series of 1,4‐DHPs through a 1,1‐difunctionalization/cyclization process. In this protocol, two C( sp 3 )−C( sp 2 ) bonds and a C( sp 2 )−N bond are simultaneously formed, the hydrogen source on the newly formed methyl group of the 1,4‐DHP skeleton is confirmed and a possible mechanism is proposed. magnified image