Sequential N-Heterocyclic Carbene-Catalyzed Reactions of Enals and Cyclic Aryldiene-1,3-Diones: Synthesis of Tricyclic Chromenones and Related Compounds

Abstract

N-Heterocycliccarbene(NHC)-catalyzedsynthe-sis of highlyfunctionalizedpyrano[3,2-c]chromene-2,5-dionederivatives, pyrano[3,2-c]quinoline-2,5(6H)-dionede-rivatives,andpyrano[4,3-b]pyran-2,5-dionederivativeswithpotentialbiological activitiesis reported. The reactionoccursthroughaKnoevenagelcondensation and NHC-cat-alyzedenolate additionin one pot.