Modified DIOPs, (4R, 5R)-4-(diaryl- or dialkylphosphino)methyl-5-(diarylphosphino)methyl-2, 2-dimethyl-1, 3-dioxolanes, were prepared on the basis of our design concept, and used as ligands for the rhodium(I)-catalyzed asymmetric hydrogenations of ketopantolactone, itaconic acid, demethyl itaconate, and β-aryl-substituted itaconic acid derivatives. A neutral rhodium(I)-complex of (4R-trans)-dicyclohexyl[[5-[(diphenylphosphino)methyl]-2, 2-dimethyl-1, 3-dioxolan-4-yl]methyl]phosphine (DIOCP) bearing both a dicyclohexylphosphino group and a diphenylphosphino group was found to be a more efficient catalyst than the original DIOP in the asymmetric hydrogenation of ketopantolactone. Modified DIOPs bearing electron-donating groups at their para positions were efficient ligands for the rhodium(I)-catalyzed asymmetric hydrogenations of itaconic acid and its derivatives; in particular, (4R-trans)-[(2, 2-dimethyl-1, 3-dioxolane-4, 5-diyl)bis(metylene)]bis[bis(4'-methoxy-3', 5'-dimethylphenyl)phosphine] (MOD-DIOP) bearing both a p-methoxy group and two m, m'-methyl groups on each phenyl group showed much higher enantioselectivity and catalytic activity than DIOP.
改良的D
IOPs,(4R, 5R)-4-(二芳基或二烷基
磷酰基)甲基-5-(二芳基
磷酰基)甲基-2, 2-二甲基-1, 3-
二噁烷,基于我们的设计概念制备,并用作
铑(I)催化的酮平滑酸、
丁烯二酸、去甲基
丁烯二酸酯和β-芳基取代
丁烯二酸衍
生物的不对称氢化的
配体。含有二环己基
磷酰基和二苯基
磷酰基的(4R-trans)-二环己基[[5-[(二苯基
磷酰基)甲基]-2, 2-二甲基-1, 3-
二噁烷-4-基]甲基]
磷酸盐(DIOCP)被发现是比原始D
IOP在酮平滑酸的不对称氢化反应中更有效的催化剂。具有电子给体基团的改良D
IOPs在其对位上是
铑(I)催化的
丁烯二酸及其衍
生物不对称氢化的有效
配体;特别是,(4R-trans)-[(2, 2-二甲基-1, 3-
二噁烷-4, 5-双基)双(亚甲基)]双[双(4'-甲氧基-3', 5'-二甲基苯)
磷](MOD-D
IOP)同时具有p-甲氧基基团和每个苯基上的两个m, m'-甲基基团,其对映选择性和催化活性显著高于D
IOP。