在水中由钼(VI)或钨(VI)吡啶醇络合物进行的顺丙烯膦酸的异相催化不对称环氧化

Heterogeneous Asymmetric Epoxidation of cis-1-Propenyl-phosphonic Acid in H2O Catalyzed by Chiral Mo(VI) or W(VI) 2'-Pyridinyl Alcoholate Complex

合成了手性吡啶醇二氧合钼(VI)及二氧合钨(VI)配合物,采用这两种配合物作为催化剂,实现了在水中对顺丙烯膦酸(CPPA)的催化不对称环氧化.这两种催化剂不溶于水,因此,这是一个发生在固液两相界面上的异相催化不对称环氧化反应.其中手性吡啶醇二氧合钼在0℃下的对映选择性ee值达到71%;加入相转移催化剂四正丁基溴化铵,催化剂的活性和对映选择性有显著提高,其中手性吡啶醇二氧合钨在50℃下ee值由54%提高到78%.手性吡啶醇二氧合钼和二氧合钨催化剂可以回收再使用.

In this paper, chiral molybdenum（Ⅵ） or tungsten（Ⅵ） 2＇-pyridinyl alcoholate complex catalyzed asymmetric epoxidation of cis-1-propenylphosphonic acid in H2O was reported. This is an asymmetric epoxidation reaction taking place on the solid-liquid interface. The highest ee value of 71% was achieved by using chiral molybdenum（Ⅵ） 2＇-pyridingyl alcoholate complex at 0℃. After addition of phase transfer catalyst Bu4NBr, the yield and ee value were remarkably increased. For example, using chiral tungsten（Ⅵ） 2＇-pyridinyl alcoholate complex at 50 ℃, the ee value was increased from 54% to 78%.