Successful Application of a Kepleratetype, Giantball Nanoporous Isopolyoxomolybdate as a Reusable Green Catalyst for Atom-economy Synthesis of Tetrahydrobenzo[a]xanthene-11-ones

In this study, a new application of a kepleratetype giantball nanoporous isopolyoxomolybdate, (NH4)42[MoVI72MoV60O372(CH3COO)30(H2O)72], denoted as ({Mo132}), in the synthesis of tetrahydrobenzo[a]xanthene11ones via a onepot, threecomponent reaction of βnaphthol, aryl aldehydes, and dimedone is reported. The reactions were performed under the solventfree conditions, providing the corresponding products with high atom economy ranging from 90.77% to 92.32%. The catalyst was prepared using inexpensive and readily available materials and could be easily recovered from the reaction mixture by a simple filtration and reused many times with no significant loss of its catalytic activity. High activity of the catalyst, excellent yields, short reaction time, simple procedure with an easy workup, and the absence of any volatile and hazardous organic solvents are other advantages of the present methodology.