Catalytic Synthesis of Pyrano- and Furoquinolines Using Nano Silica Chromic Acid at Room Temperature

Abstract EN

Nano silica chromic acid (nano-SCA) is found to catalyze efficiently the three component-coupling reactions of aldehydes, amines, and cyclic enol ethers such as 3,4-dihydro-2H-pyran and 2,3-dihydrofuran under mild conditions to afford the corresponding pyrano- and furanoquinolines in excellent yields with high endoselectivity.

Interestingly, 2,3-dihydrofuran afforded selectively endoproducts under the similar reaction conditions.

Heterogeneous reaction conditions, easy procedure, short reaction time, and high yields are some important advantages of this method.