Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipole and Base Catalyzed Michael Addition with β-Nitrostyrene via C3 Umpolung of Oxindole

A new isatin N,N'-cyclic azomethine imine 1,3-dipole was devised, and an unusual Michael addition with beta-nitrostyrene catalyzed by tributylamine under mild conditions has been developed. The new reaction featured the C3 umpolung of oxindole and an unusual formation of double bond. Notably, this new synthon performed as a donor rather than an acceptor. This protocol provided a promising method for the preparation of various 3-aminooxindoles with good yields in moderate diastereoselectivities.