A convenient
approach to [1,2,5]oxadiazolo[3′,4′:5,6]pyrazino[2,3-b]indoles and their heteroannulated analogues bearing various
aryl substituents in the backbone has been developed. This synthetic
protocol is based on Pd-catalyzed Buchwald–Hartwig and subsequent
annulation by intramolecular oxidative cyclodehydrogenation. The photophysical
properties for new polycycles have been measured.