I2-Catalyzed intramolecular dehydrogenative aminooxygenation of alkynes to acylated imidazo[1,2-a]pyridines and indolizines

An efficient and green protocol for the synthesis of acylated imidazo[1,2-a]pyridines and indolizines via intramolecular dehydrogenative aminooxygenation of alkynes has been developed. The reaction proceeds smoothly utilizing I2 as a catalyst and TBHP as an oxidant with a broad substrate scope. Mechanism studies reveal that the reaction maybe experiences a hydration followed by an oxidative cycloamination process.