Rhodium(III)-Catalyzed Annulation of 2-Alkenyl Anilides with Alkynes through C-H Activation: Direct Access to 2-Substituted Indolines

A Rh-III complex featuring an electron-deficient eta(5)-cyclopentadienyl ligand catalyzed an unusual annulation between alkynes and 2-alkenyl anilides to form synthetically appealing 2-substituted indolines. Formally, the process can be viewed as an allylic amination with concomitant hydrocarbonation of the alkyne. Mechanistic experiments indicate that this transformation involves an unusual rhodium migration with a concomitant 1,5-H shift.