Domino Prins/pinacol reaction for the stereoselective synthesis of spiro[pyran-4,4′-quinoline]-2′,3′-dione derivatives

Abstract

A wide array of aldehydes undergo smooth cross-coupling with 3-hydroxy-3-(4-hydroxybut-1-en-2-yl)-1-methylindolin-2-one in the presence of 10 mol% BF3·OEt2 at 0 °C in dichloromethane to afford the corresponding 2,3,5,6-tetrahydro-1'H-spiro[pyran-4,4'-quinoline]-2',3'-dione derivatives in good yields with excellent diastereoselectivity. This is the first report on the synthesis of tetrahydro-1'H-spiro[pyran-4,4'-quinoline]-2',3'-dione scaffolds through a cascade of Prins/pinacol reactions.

Catalyst-Free, Room-Temperature Accessible Regioselective Synthesis of Spiroquinolines and Their Antioxidant Study

“…Highly volatile solvents often cause fires and/or detonations, resulting in destruction. Therefore, the attempt made to explore organic synthesis in aqueous solvents, deep eutectic solvents, and ionic liquids are in high demand. − The reactions which lead to successful conversion in aqueous media are gaining much more attention in synthetic organic chemistry not only because water is abundant in nature but due to extensive hydrogen bonding, inexpensive, environmentally benign, high dielectric constant, non-flammability, eco-compatibility, and selectivity in many organic reactions than conventional organic solvents. − …”