Enantioselective Synthesis of Polycyclic Nitrogen Heterocycles by Rh-Catalyzed Alkene Hydroacylation: Constructing Six-Membered Rings in the Absence of Chelation Assistance

Catalytic, enantioselective hydroacylations of N-allylindole-2-carbox­aldehydes and N-allylpyrrole-2-carbox­aldehydes are reported. In contrast to many alkene hydroacylations that form six-membered rings, these annulative processes occur in the absence of ancillary functionality to stabilize the acylrhodium­(III) hydride intermediate. The intramolecular hydroacylation reactions generate 7,8-dihydro­pyrido­[1,2-a]­indol-9­(6H)­ones and 6,7-dihydro­indolizin-8­(5H)-ones in moderate to high yields with excellent enantioselectivities.