β-CYCLODEXTRIN IN WATER: HIGHLY VERSATILE AND GREEN APPROACH FOR BIOMIMETIC REGIOSELECTIVE RING OPENING OF CHALCONE EPOXIDES WITH NITROGEN HETEROCYCLES

The formation of new C-C bond through highly regioselective ring opening of chalcone epoxides to nitrogen-containing heterocycles has been effectively worked out in impressive yields with heterocyclic nucleophiles such as pyrrole, indole, and 2-methyl indole in the presence of -cyclodextrin using water as solvent at room temperature within 25-50min. Water, an environmentally friendly reaction medium, has been utilized for the first time for the reaction of these heterocyclic nucleophiles with chalcone epoxides as their -cyclodextrin complexes to afford 1,3-diaryl-2-hydroxy-3-(1H-3-indolyl/2-pyrrolyl)propan-1-ones (3a-u). The catalyst can be easily recovered and recycled for several times without loss of activity.