The addition reaction of cyclohexylmethylmagnesium bromide with the imine prepared from unnatural(2S, 3S)-tartaric acid was found to proceed in a highly stereoselective manner in the presence of cerium(III) chloride. A chelation-controlled mechanism could explain the stereochemical outcome of the addition reaction. The addition product could be elaborated into three types of C-terminal components of renin inhibitors by employing oxidative cleavage of the 1, 2-diol moiety, epoxide formation with inversion of configuration, and epoxide opening with a nucleophile.
环己基
甲基溴化镁与非天然(2S, 3S)-
酒石酸制备的
亚胺的加成反应,在
氯化
铈(III)存在下,表现出高度的立体选择性。螯合控制机制可以解释加成反应的立体
化学结果。加成产物可以通过1, 2
-二醇部分的氧化断裂、构型反转的环氧化反应和与亲核试剂的环氧化开环反应,进一步转化为三种类型的
血管紧张素转化酶抑制剂的C端部分。