CuCl/air-mediated oxidative coupling reaction of imidazoheterocycles with N-aryl glycine esters

A copper/air mediated oxidative coupling reaction of imidazoheterocycles with N-aryl glycine esters is here described. The reaction proceeded effectively under an air atmosphere without the use of peroxide agents. This simple protocol allows for the preparation of a wide range of imidazoheterocycles with a glycine ester motif, which are of great interest in the field of medicinal chemistry. Interestingly, the coupling of imidazo[1,2-a]pyridine with secondary or tertiary α-amino phenylethanone selectively affords the imidazo[1,2-a]pyridin-3-yl imine or imidazo[1,2-a]pyridin-3-yl diketone in the presence of CuCl and TBHP (tertbutyl hydroperoxide).