Cu(OTf)2/TBHP/O2-Mediated Tandem Oxidative Reaction: Easy Access to Benzopyrano[4,3-b]pyridines

Abstract

An effective tandem reaction of 4-aminocoumarins and 1,3-diarylpropenes mediated by Cu(OTf)2/TBHP (tert-butyl hydroperoxide)/O2 is disclosed, which provides various benzopyrano[4,3-b]pyridines in moderate to good yields. It undergoes oxidative coupling, intramolecular cyclization, and dehydro-aromatization. This approach has the advantages of high atom economy, environmental friendliness, and wide substrate scope.