Magnetite L-proline as a reusable nano-biocatalyst for efficient synthesis of 4H-benzo[b]pyrans in water: a green protocol

Abstract

L-Proline is known as the most favored organocatalyst in enamine-mediated reactions. Magnetic functionalization of this organocatalyst could solve its recovery and reuse problems. Herein we report the use of magnetic L-proline nano-biocatalyst for a simple and efficient one-pot coupling reaction of dimedone, malononitrile, and aromatic aldehydes to afford the corresponding tetrahydrobenzo[b]pyrans as a significant class of heterocyclic compounds with great biological and pharmacological importance according to a green protocol. Low cost, facile handling, simple preparation, high stability, reusability, and low toxicity are some remarkable features of this nano-biocatalyst.