Isatin <i>N</i>,<i>N</i>′‑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 β-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.本研究设计合成了一种新型靛红N,N′-环型甲亚胺亚胺1,3-偶极子（isatin N,N′-cyclic azomethine imine 1,3-dipole），并开发了一种以三丁基胺（tributylamine）为催化剂、在温和条件下与β-硝基苯乙烯（β-nitrostyrene）发生的非常规迈克尔加成（Michael addition）反应。该反应以羟吲哚（oxindole）的C3极性反转以及非常规双键形成为特征。值得关注的是，该新型合成子（synthon）充当供体而非受体。该合成策略为制备多种兼具良好收率与中等非对映选择性的3-氨基羟吲哚（3-aminooxindoles）提供了极具应用前景的方法。