A highly stereoselective and general method for the synthesis of the C1-C11 fragment of borrelidin has been achieved. The main feature of our synthetic route is enzymatic desymmetrization to create two methyl bearing chiral centres, use of Evans auxiliary to introduce two other methyl groups and creation of C3 stereocentre by regioselective opening of an epoxide arising from Sharpless epoxidation protocol. The synthesis of the C1-C11 subunit was achieved in gram scale by a linear synthetic sequence in an overall yield of 18.4%.
已实现一种高度立体选择性和通用性的方法,用于合成博雷利丁的C1-C11片段。我们合成路线的主要特点是通过酶解对称化反应创造两个含甲基的手性中心,使用Evans辅助基团引入其他两个甲基,并通过区域选择性开环反应生成来自Sharpless环氧化协议的
环氧化物,创建C3手性中心。C1-C11亚单位的合成以线性合成序列在克级规模上实现,总体产率为18.4%。