Studies on the 1,2-Migrations in Pd-Catalyzed Negishi Couplings with JosiPhos Ligands
作者:Anders T. Lindhardt、Thomas M. Gøgsig、Troels Skrydstrup
DOI:10.1021/jo801824e
日期:2009.1.2
cross-coupling, which is promoted by palladium catalyst systems generated with JosiPhos ligands. Several of the factors that were demonstrated to be important for the 1,2-migration include (1) the nucleophilicity of the organometallic reagent, which possibly influences the transmetalation step in direct competition with the intermediate β-hydride elimination of the alkenyl Pd(II) species; (2) the structural
我们报告了一项初步调查,目的是确定控制Negishi交叉偶联中1,2-迁移的因素,这是由JosiPhos配体生成的钯催化剂体系促进的。已证明对1,2-迁移很重要的几个因素包括(1)有机金属试剂的亲核性,这可能会影响烯基金属钯(II)的中间β-氢化物消除与直接竞争中的重金属化步骤) 物种; (2)甲苯磺酸甲苯酯和磷酸酯的结构特征,其中具有大体积C1取代基的底物在偶联反应条件下表现出最高的1,2-迁移倾向。(3)JosiPhos配体的结构,