Efficient synthesis of α- and δ-carbolines by sequential Pd-catalyzed site-selective C–C and twofold C–N coupling reactions

Abstract

Two concise and efficient approaches were developed for the synthesis of α- and δ-carboline derivatives. The success of the synthesis relies on site-selective Suzuki–Miyaura reactions of 1-chloro-2-bromopyridine or 2,3-dibromopyridine with 2-bromophenylboronic acid and subsequent cyclization with amines which proceeds by twofold Pd-catalyzed C–N coupling reactions.