Novel One-pot Synthesis of Pyranocarbazole Derivatives via an Isocyanidebased Three-component Reaction

An efficient method has been developed for the synthesis of new pyrano[3,2-c] and pyrano[3,2-a]carbazole derivatives via a three-component reaction of 4-hydroxycarbazole or 2-hydroxycarbazole, isocyanides, and dialkylacetylenedicarboxylates. Noteworthy features of this protocol include mild reaction conditions, catalyst-free, high atom-economy and high yields.