Synthesis of new N-substituted chiral phosphine–phosphoramidite ligands and their application in asymmetric hydrogenations and allylic alkylations
作者:Szabolcs Balogh、Gergely Farkas、Imre Tóth、József Bakos
DOI:10.1016/j.tetasy.2015.05.001
日期:2015.7
catalyzed asymmetric allylic alkylation of rac-(E)-1,3-diphenylallyl acetate. Remarkably high activity (up to 1780 h−1 turnover frequency) and first order kinetics were observed by facilitating nucleophile formation. The substituent at the nitrogen and the configuration of chiral moieties had a high impact on the enantioselectivity. The new ligands were also tested in the rhodium-catalyzed asymmetric hydrogenation
含有2,4-戊二基骨架,BINOL部分,和Me,BN或pH取代基上的氮膦-亚磷酰胺配位体的合成和完全表征。所述的电子效应Ñ通过检查-取代基31及其相应的硒代磷酸酰胺和膦硒化物衍生物的P NMR。新配体与它们之前的报道衍生物一起在钯催化的不对称烯丙基烷基化进行测试外消旋( - ë)-1,3- diphenylallyl乙酸酯。值得注意的活性高(高达1780 ^ h -1周转频率)和一阶动力学通过促进亲核体形成观察。在氮上的取代基和手性部分的构型对对映体选择性高的影响。新的配体,可以在甲基(的铑催化的不对称氢化测试Ž)-α-acetamidocinnammate,衣康酸二甲酯(高达99.9%ee的的)和甲基2-乙酰氨基(高达99.5%ee)的。