I 2 -catalyzed intramolecular oxidative amination of C(sp 3 )-H bond: efficient access to 3-acylimidazo[1,2- a ]pyridines under neat condition.

An efficient and "green" protocol for the synthesis of 3-acylimidazo[1,2- a ]pyridines through intramolecular oxidative α-amination of carbonyl compounds has been developed. The reaction proceeds smoothly utilizing I 2 as a catalyst and H 2 O 2 as an oxidant under neat condition with broad substrate scope. Several complex nitrogen-containing fused rings are conveniently constructed, which are not easy to access by traditional methods.