Highly Enantioselective Lewis Acid Catalyzed Conjugate Addition of Imidazo[1,2‑<i>a</i>]pyridines to α,β-Unsaturated 2‑Acylimidazoles under Mild Conditions

A highly enantioselective protocol for the conjugate addition of 2-arylimidazo[1,2-a]pyridines and other imidazo derivatives to α,β-unsaturated 2-acylimidazoles is described. The method uses a previously reported chiral-at-metal rhodium catalyst and provides the corresponding adducts in yields of 25–98% with enantioselectivities up to er > 99:1. Additionally, the transformation proceeds under mild conditions using ethanol as the solvent at room temperature.