Organocatalytic Enantioselective Michael Addition between 3-(3-hydroxy-1H-pyrazol-1-yl)Oxindole and β-Nitrostyrene for the Preparation of Chiral Disubstituted Oxindoles

A new enantioselective Michael addition between 3-(3-hydroxy-1 H -pyrazol-1-yl)oxindole, a new synthon generated from isatin N, N′ -cyclic azomethine imine 1,3-dipole, and β-nitrostyrene has been disclosed. A series of chiral 3-(3-oxo-2,3-dihydro-1 H -pyrazol-1-yl) disubstituted oxindoles were obtained in excellent results (up to 97% yield, up to 94% ee) with moderate to good diastereoselectivities (up to 4.3:1 dr).