Optimisation of enantioselectivity for the chiral base-mediated rearrangement of bis-protected meso-4,5-dihydroxycyclohexene oxides: asymmetric synthesis of 4-deoxyconduritols and conduritol F
作者:Simon E de Sousa、Peter O'Brien、Christopher D Pilgram
DOI:10.1016/s0040-4020(02)00370-8
日期:2002.6
based on diastereoselective epoxidation of a cyclohexene followed by chiral lithium amide-mediated epoxide rearrangement has been used to synthesise an allylic alcohol building block of >95% ee. The key step is the enantioselective rearrangement of a bis-protected meso-4,5-dihydroxycyclohexene oxide. A range of protecting groups and chiral base structures were surveyed in order to find the optimum protocol
一种基于环己烯的非对映选择性环氧化然后手性锂酰胺介导的环氧化物重排的策略已用于合成> 95%ee的烯丙醇结构单元。关键步骤是双保护的内消旋-4,5-二羟基环己烯氧化物的对映选择性重排。调查了一系列保护基团和手性碱基结构,以发现高对映选择性的最佳方案。使用叔丁基二甲基甲硅烷氧基保护基团和降麻黄碱衍生的手性碱,获得了> 95%ee的93%的烯丙醇收率。为了证明其合成实用性,该烯丙醇随后被转化为4-脱氧康杜糖醇和(+)-康杜糖醇F。