Air-Stable, Phosphine-Free Anionic Palladacyclopentadienyl Catalysts: Remarkable Halide and Pseudohalide Effects in Stille Coupling
作者:Catherine M. Crawforth、Ian J. S. Fairlamb、Anant R. Kapdi、José Luis Serrano、Richard J. K. Taylor、Gregorio Sanchez
DOI:10.1002/adsc.200505325
日期:2006.3
The Stille cross-coupling of allylic and benzyl bromides is shown to proceed efficiently using phosphine-free dinuclear anionic palladacyclopentadienyl catalysts possessing bridging (N,O)-imidate ligands. The type of bridging anion influences the catalytic activity considerably. Halide anions such as chloride, bromide or iodide also influence the catalytic activity but to a far lesser extent than the
使用具有桥联的(N,O)-亚氨酸酯配体的无膦的二核阴离子阴离子缩水铝环戊二烯基催化剂,可以有效地进行烯丙基和苄基溴的斯蒂勒交叉偶联。桥连阴离子的类型极大地影响催化活性。卤化物阴离子(例如氯离子,溴离子或碘离子)也会影响催化活性,但程度要比假卤代亚氨酸根阴离子(来自琥珀酰亚胺或邻苯二甲酰亚胺)小得多。在40°C下在DMF中存在两个当量的CsF的情况下,使用CuI作为助催化剂,使用7a可以看到鲍德温型协同效应。在甲苯中,这些添加剂会减慢底物的周转率。