Site-Selective C-H Functionalization of N-Aryl and N-Heteroaryl Piperidines, Morpholines, and Piperazines Controlled by a Chiral Dirhodium Tetracarboxylate Catalyst

Rhodium-catalyzed C-H insertion by donor/acceptor carbenes is a useful transformation in organic synthesis. However, the site-selectivity of the C-H transformation on the target molecule is often a major issue. Site-selective C-H functionalizations of challenging substrates like N -aryl-and N-heteroaryl piperidines could be achieved through chiral rhodium carbene intermediates, leading to the formation of highly stereoselective C-2 products. In addition, N-aryl morpholines and piperazines were selectively reacted at the alpha position to the N-aryl group.