Synthesis of Partially Reduced Imidazo[1,2-a]pyridines through an Unprecedented Base-Mediated (4+2) Cyclization

A water-mediated regioselective synthesis of 6,7-diaryl-5-oxo-2,3,5,6-tetrahydroimidazo[1,2- a ]pyridine-6-carbonitriles was performed by the reaction of 2-[1-cyano-2,2-bis(methylsulfanyl)vinyl]benzonitrile with 1-aryl-2-(imidazolidin-2-ylidene)ethanones under basic conditions. This reaction involves an unprecedented (4+2) annulation.