Promising Molecules for Optoelectronic Applications: Synthesis of 5,10‐Dihydrobenzo[a]indolo[2,3‐c]carbazoles by Scholl Reaction of 1,2‐Bis(indol‐2‐yl)benzenes

Abstract

Only a few straightforward procedures for the preparation of indolo[2,3‐c]carbazoles are known, despite promising features for material applications. Herein we present a convenient synthesis of 5,10‐dihydrobenzo[a]indolo[2,3‐c]carbazoles using an oxidative cyclization of 1,2‐bis(1H‐indol‐2‐yl)benzenes prepared from readily accessible starting materials. Functionalization through electrophilic aromatic substitution reactions and palladium‐catalyzed cross‐coupling reactions were investigated, which lead to the isolation of new functionalized 5,10‐dihydrobenzo[a]indolo[2,3‐c]carbazoles, whose steady state electronic spectroscopy has been examined.