Montmorillonite KSF clay-promoted synthesis of enantiomerically pure 5-substituted pyrazoles from 2,3-dihydro-4H-pyran-4-ones

2,3-Dihydro-4H-pyran-4-ones derived from d-glucal undergo rapid condensation with aryl hydrazines in the presence of montmorillonite KSF clay under mild conditions to afford a novel class of chiral 5-substituted pyrazoles in good yields with high selectivity. The stereochemical assignments of the products were achieved by NMR studies.