enantioselective alkylation of vinyl azides with 3-bromo-3-substituted oxindoles was achieved through a chiral N,N′-dioxide/Ni(OTf)2-mediated conjugate addition/water addition/elimination tandem process. Water was critical to the chemo- and enantioselectivity. The hydrated Na3PO4 acted as both a base and a reservoir to regulate the amount of water in solution. A wide range of enantioenriched oxindoles having
通过手性N,N'-二氧化物/Ni(OTf) 2介导的共轭加成/加水/消除串联过程,实现了乙烯基叠氮化物与 3-溴-3-取代羟吲哚的高度化学选择性和对映选择性烷基化。水对化学选择性和对映选择性至关重要。水合 Na 3 PO 4既作为碱基又作为储库来调节溶液中的水量。以良好的产率和良好的 ee 值(51 个实例,高达 90% 的产率,97% ee)获得了具有 α-羰基取代的全碳季立构中心的各种对映体富集的羟吲哚。将产品轻松转化为 (+)-physovenine 和 (+)-desoxyeseroline 的类似物提高了合成价值。包括控制实验、动力学研究和密度泛函理论 (DFT) 计算在内的机理研究支持提出可能的催化循环以及过渡态,以阐明反应过程和手性诱导。
Organocatalyzed Enantioselective Decarboxylative Stereoablation Reaction for the Construction of 3,3′-Disubstituted Oxindoles Using β-Ketoacids and 3-Halooxindoles
unprecedented method for the construction of opticallyactive 3,3′-disubstituted oxindoles via an organocatalyzed decarboxylative stereoablation reaction has been developed. We describe the first asymmetric reaction between β-ketoacids and 3-halooxindoles utilizing an organocatalyst. This method allows for the formation of a variety of 3,3′-disubstituted oxindoles bearing a keto-carbonyl group, which