Cu-Catalyzed Synthesis of Imidazo[1,2-a]pyridines from α-Diazoketones and 2-Aminopyridines

Significance

A synthesis of imidazo[1,2-a]pyr­idines by copper-catalyzed reaction of 2-amino­pyridines with α-diazoketones is reported. The reaction proceeds in high yield under convenient and mild conditions from readily available starting materials. Although variation of R⁴, including a chiral example, was moderately explored, pyridine substitution was poorly investigated. A plausible mechanism involving a copper triflate catalyzed condensation of the aniline with the diazoketone, and subsequent ring closure via ejection of nitrogen was proposed.