Gold(I)-Catalyzed Cyclization of Ene–Ynamide Carboxylates Involving 1,2-Group Migration: Synthesis of Functionalized 2-Acylquinolines

A gold-catalyzed cascade cyclization of ene-ynamides bearing a propargyl carboxylate moiety has been developed, which involves a 1,2-migration of the alkene substituent as a key step. The method provides an efficient route for the synthesis of functionalized 2-acylquinolines, with high selectivity favoring 1,2-aryl migration over 1,2-H or -alkyl migration. In addition, the nature of the propargylic substituent has a significant effect on the reaction outcome. When an aryl substituent is present, 2-indenyl-substituted indole is formed via a cyclopropyl gold carbene intermediate, leading to cleavage of the C═C bond in the ene-ynamide substrate.