Molecular sieve mediated sequential Knoevenagel condensation/decarboxylative Michael addition reaction: efficient and mild conditions for the synthesis of 3,3-disubstituted oxindoles with an all carbon quaternary center

A mild, catalyst-free and efficient molecular sieve mediated sequential Knoevenagel condensation/decarboxylative Michael additon reaction has been developed. A broad scope of 3,3-disubstituted oxindoles were synthesized in good to excellent yields.