Preparation of polyfunctional aryl and alkenyl zinc halides from functionalized unsaturated organolithiums and their reactivity in cross-coupling and conjugated addition reactions
作者:Ingo Klement、Mario Rottländer、Charles E. Tucker、Tahir N. Majid、Paul Knochel、Patricia Venegas、Gérard Cahiez
DOI:10.1016/0040-4020(96)00246-3
日期:1996.5
organolithiums which are stable for a short time at these low temperatures and can be transmetalated to organozinc derivatives by the addition of zinc bromide. The resulting unsaturated organozinc halides can then be warmed up and are perfectly stable at 25 °C. They react directly with tosyl cyanide. In the presence of CuCN·2LiCl, they add in a Michael-fashion to alkylidenemalonates. In the presence
功能化的芳基碘和烯基碘化物在-90至-80°C的条件下进行碘-锂交换,从而提供了在这些低温下短时间内稳定的多官能有机锂,可以通过添加溴化锌将其转变为有机锌衍生物。然后可以加热所得的不饱和有机锌卤化物,并在25°C下完全稳定。它们直接与甲苯磺酰氰反应。在CuCN·2LiCl的存在下,它们以Michael形式加入到亚烷基丙二酸酯中。在催化量的Pd(dba)2和TPP或TFP的存在下,它们很容易在25°C与芳基和烯基碘化物发生交叉偶联。通过使用dppf作为配体和60°C作为反应温度,也可以实现芳基溴化锌与芳基三氟甲磺酸酯的Pd催化偶联。