Borax catalyzed domino reactions: synthesis of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes

Abstract

Borax, an innocuous, inexpensive, and a naturally occurring material, very efficiently catalyzes the Knoevenagel condensation and Michael addition in domino fashion for the construction of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes. The present protocol offers advantages in terms of higher yields, wide scope of substrates, operational simplicity, short reaction time, no requirement of workup or column chromatography, and easy access to a wide range of structurally diverse functionalized molecules of biological importance. Recycling of the catalyst and scaling up of the reactions are important attributes of this catalytic process.