Synergistic Steric Effects in the Development of a Palladium‐Catalyzed Alkyne Carbohalogenation: Stereodivergent Synthesis of Vinyl Halides
作者:Christine M. Le、Perry J. C. Menzies、David A. Petrone、Mark Lautens
DOI:10.1002/anie.201409248
日期:2015.1.2
our finding that by exploiting the synergistic steric effects between substrate and catalyst, an intramolecular Pd‐catalyzed alkyne carbohalogenation can be achieved. This operationally simple method uses the bulky Pd/Q‐Phos combination and allows access to tetrasubstituted vinyl halides from the corresponding aryl chlorides, bromides, and iodides. Steric effects in the substrate play a key role by
我们报告了我们的发现,即通过利用底物和催化剂之间的协同空间效应,可以实现分子内Pd催化的炔烃碳卤化反应。这种操作简单的方法使用了笨重的Pd / Q-Phos组合,可从相应的芳基氯化物,溴化物和碘化物中获得四取代的乙烯基卤化物。底物中的立体效应通过促进C卤素的还原消除并促进催化转化发挥关键作用。通过可逆的氧化加成机理,在升高的温度下观察到热力学驱动的异构化反应。因此,通过改变反应温度,反应的两种立体异构体变得容易接近。