Et3N-catalyzed oxidative dehydrogenative coupling of α-unsubstituted aldehydes and ketones with aryl diamines leading to quinoxalines using molecular oxygen as oxidant

A novel Et3N-catalyzed oxidative dehydrogenative coupling of α-unsubstituted carbonyl compounds with aryl diamines leading to quinoxaline derivatives using molecular oxygen as oxidant has been developed. Six hydrogen dissociations involving 2 sp3 C-H bonds activation are realized under mild conditions in this approach. Plausible mechanism is proposed for this novel Et3N-catalyzed transformation on the basis of the aboratively designed mechanistic studies including the radical detection by EPR. ©2012 Elsevier Science. All rights reserved.