the dioxolane ring had a small effect on the asymmetric induction by DIOP in the hydrogenation. Modification at the phosphino group affected the stereocontrol by the ligand and the unsymmetrical DIOP with di-2-naphthylphosphino group gave higher optical yields than (−)-DIOP for the hydrogenation of α-acetamidocinnamic acid and dehydrodipeptides.
(-)-D
IOP 以两种方式进行了修饰:i),在 (-)-D
IOP 的二
氧戊环上引入了一个大的芳族取代基,以及 ii),用二芳基膦基取代一个
二苯基膦基,得到不对称的 D
IOP。二
氧戊环的修饰对氢化中D
IOP的不对称诱导影响很小。膦基的修饰影响了
配体的立体控制,并且对于 α-乙酰
氨基
肉桂酸和脱氢二肽的氢化,具有二-2-
萘基膦基的不对称 D
IOP 比 (-)-D
IOP 产生更高的光学产率。