Molybdate sulfuric acid (MSA) has been found as an efficient and reusable solid acid catalyst for the synthesis of new 2,3,4,5-tetrasubstituted pyrroles via a novel [2+2+1] strategy. Thus, one-pot three-component reaction of benzoin derivatives, 1,3-dicarbonyls, and ammonium acetate afforded the desired products in high yield under solvent-free conditions. (C) 2012 Elsevier B.V. All rights reserved.