Base-Catalyzed Sequential 1,4-Addition/Intramolecular Cyclization/Aromatization Reaction: Synthesis of Benzofuro[3,2-b]pyridines.

An efficient K2CO3-catalyzed 1,4-addition/intramolecular cyclization/aromatization reaction of aurone-derived 1-azadienes with trisubstituted allenoates has been developed, giving a series of benzofuro[3,2-b]pyridines in moderate to excellent yields. The reaction proceeded efficiently under an air atmosphere without the use of transition metal catalysts. This protocol provides a concise approach to benzofuro[3,2-b]pyridines.