Ultrasound Assisted Regioselective Synthesis of Polyhydrospiro [indoline-3,3’-pyrrolizine]-2-one Library via Multicomponent Cycloaddition Reaction

Present work demonstrates the ultrasound mediated synthesis of new Hexahydrospiro[indoline-3,3’pyrrolizine]-2-one derivatives in excellent yields via [3+2] cycloaddtion reaction in regioselective manner under ultrasonic irradiation. Multicomponent reaction of substituted 3-cinnamoyl-4-hydroxy-6-methyl-2H-pyran-2-one, isatin, L-proline was utilized for synthesis of spiro framework in regioselective manner at room temperature. All the synthesized hexahydrospiro molecules were characterized by H and C NMR, IR spectra, mass spectra and elemental analysis. Regioselective nature of reaction was explained on the basis of secondary orbital interactions. We have developed a very simple and facile methodology that has great importance in synthetic chemistry.