Oxidative addition of N-halosuccinimides to palladium(0): the discovery of neutral palladium(II) imidate complexes, which enhance Stille coupling of allylic and benzylic halides
作者:Catherine M. Crawforth、Suzanne Burling、Ian J.S. Fairlamb、Anant R. Kapdi、Richard J.K. Taylor、Adrian C. Whitwood
DOI:10.1016/j.tet.2005.06.080
日期:2005.10
mediate the Stille coupling of allylic and benzylic halides with alkenyl, aryl and allyl stannanes. In competition experiments between 4-nitrobromobenzene and benzyl bromide with a cis-stannylvinyl ester, (Ph3P)2Pd(N-Succ)Br preferentially cross-couples benzyl bromide, whereas with other commonly employed precatalysts 4-nitrobromobenzene undergoes preferential cross-coupling. Furthermore, preferential
已经研究了由空气和湿气稳定的含有琥珀酰亚胺或邻苯二甲酰亚胺(亚氨酸酯)配体的钯(II)膦配合物介导的有机锡烷和有机卤化物的斯蒂勒偶联。已经开发出一种有效的合成路线,以合成几种含有琥珀酰亚胺和邻苯二甲酰亚胺配体的钯(II)配合物。顺式-溴代双(三苯基膦)(N-琥珀酰亚胺)钯(II)[(Ph 3 P)2 Pd(N -Succ)Br]被证明可介导烯丙基和苄基卤化物的Stille偶联与烯基,芳基和烯丙基锡烷。在4-硝基溴苯和苄基溴与顺式-锡烷基乙烯基酯(Ph 3 P)2的竞争实验中Pd(N -Succ)Br优先使苄基溴交联,而与其他常用的预催化剂4-硝基溴苯进行优先交叉偶联。此外,首次观察到失活的苄基溴优先于活化的苄基溴的反应。卤化物的类型和琥珀酰亚胺配体的存在对于有效的Stille偶联至关重要。还显示出膦配体的类型改变了钯(II)琥珀酰亚胺配合物的催化活性。