A Catalyst-Free One-Pot Multicomponent Green Strategy for the Synthesis of Spiroindene-1,3dione-Benzochromene/ Thio-Chromene Derivatives under Neat/Aqueous Conditions

An efficient, facile, and catalyst-free one-pot multicomponent green strategy under neat or aqueous conditions has been developed to synthesize a series of spiro compounds that contain two biologically active pharmacophores, benzochromenes/thio-chromenes and indan-1,3-dione, in a single molecular framework. The desired Spiroindene-1,3dione-benzochromene/thio-chromene derivatives were yielded through a one-pot, three-component reaction between ninhydrin, substituted 1,3-dicarbonyls, and 2-naphthol/2-naphthalene thiol via the Knoevenagel–Michael cascade. The advances of this strategy include high product yields (94–82%), the formation of a new asymmetric center, cost-effectiveness, atom economy, and a straightforward workup procedure that does not require any additional purification steps.