Regioselective synthesis of novel dispiro oxindole-pyrrolizine-thiazolidine-2,4-dione hybrids

The 1,3-dipolar cycloaddition of azomethine ylide generated in situ from isatin and proline to a series of (Z)-5-arylidene-3-(2-cyclopropyl-1-(2-fluorophenyl)-2-oxoethyl)-thiazolidine-2,4-diones led to the unprecedented formation of dispiro oxindole-pyrrolizine-thiazolidine-2,4-dione hybrids contrary to the commonly observed regiochemistry.