Ruthenium-catalyzed direct C-3 oxidative olefination of imidazo[1,2-a]pyridines

A highly regioselective oxidative olefination of imidazo[1,2-a]pyridines with acrylates has been accomplished in the presence of ruthenium catalysts to form only the C-3 coupling products. The oxidative olefination has provided step economical access to diversely substituted imidazo[1,2-a] pyridine derivatives with excellent C-3 regioselectivity and E-stereoselectivity.