Asymmetric hydroformylation of styrene catalyzed by pyranoside diphosphite-rh(Ⅰ) complexes

Abstract

合成了四个从葡萄糖及半乳糖衍生的手性芳基双膦配体,制备了手性双膦-铑(Ⅰ)配合物催化剂,并将其用于苯乙烯不对称氢甲酰化反应中.结果表明,葡萄糖骨架手性中心与联萘基之间有协同作用,对映体过量值和转化率受配体C-4骨架立体中心的绝对构型影响,而产物的绝对构型则主要由联萘单元控制;配体4-双{[(S)-1,1′-联萘基-2,2′-双基]-磷}-苯基-3,6-脱水-β-D-葡萄糖的吡喃糖苷基和联萘基的匹配组合,给出41%的对映体选择性和74∶26(异构/正构)区域选择性. Several chiral aryl diphosphite ligands derived from pyranoside backbones of glucose and galactose were applied in Rh-catalyzed asymmetric hydroformylation of styrene.A synergic effect between the chiralities of glucose and the binaphthyl moieties was observed.The sense of enantioselectivity is mainly controlled by the binaphthyl moieties,and the chirality of the sugar moiety can also affect the enantioselectivity of the reactions.In the case of the matching combination of phenyl-3,6-anhydro-β-D-glucopyranoside and binaphthyl moiety,4-bis｛[(S)-1,1’-binaphthyl-2,2’-diyl]-phosphite｝-phenyl-3,6-anhydro-β-D-gluco-pyranoside(L4),41% ee and 74∶26 of branch-to-normal ratio were obtained.