Zn( L-proline)2 as a powerful and reusable organometallic catalyst for the very fast synthesis of 2-amino-4H-benzo[g]chromene derivatives under solvent-free conditions

An efficient route for the synthesis of 2-amino-4H-benzo[g]chromenes via a three-component coupling reaction of aldehydes, malononitrile and 2-hydroxy-1,4-naphthaquinone in the presence of Zn( L-proline)(2) is reported. High yields, short reaction times, non-toxicity and recyclability of the catalyst, and easy work-up are the main merits of this protocol. Copyright (c) 2015 John Wiley & Sons, Ltd.