3-dibenzyl-2-imidazole-4,5-dicarboxylic acid (2). The bifunctional cinchona alkaloid-derived squaramide-promoted enantioselective alcoholysis was utilizing as a tool for the construction of two contiguous stereocenters of C-3a and C-6a in biotin molecular with excellent enantioselectivity. In addition, the 4-carboxybutyl side chain was assembled by first using C4+C1 approach via a novel tricyclic thiophanium
(+)-
生物素(1)的有效立体控制全合成是通过罗氏内酯5从顺式1,3-二苄基-2-
咪唑-4,5-二羧酸(2)开始的中间体实现的。双功能
金鸡纳
生物碱衍生的方胺促进的对映选择性醇解被用作构建具有优异对映选择性的
生物素分子中C-3a和C-6a两个连续立体中心的工具。另外,首先通过新颖的
三环噻吩鎓盐中间体使用C4 + C1方法组装4-羧基丁基侧链。