HBF4-Catalyzed 3,6-Bis-diarylmethylation of Carbazoles with para-Quinone Methides

Abstract

In this article, we demonstrate an atom economical, practical, mild and selective HBF4-catalyzed 1,6-conjugate addition of carbazoles to para-Quinone Methides (p-QMs) to access 3,6-bis-diarylmethyl- and mono-diarylmethyl carbazoles. This metal and additive free protocol provides convenient access to the substituted carbazole derivatives in moderate to excellent yields with a good functional group tolerance. It was found that a couple of 3,6-disubstituted carbazoles showed interesting photophysical properties and, therefore, might potentially find some applications as host materials in OLEDs.