作者:Xiaochuan Chen、Jinchun Chen、Michael De Paolis、Jieping Zhu
DOI:10.1021/jo050408k
日期:2005.5.1
An efficient synthesis of a fully functionalized tetracycle (A-B-C-H) 7 containing a 1,4-bridged 10-membered lactone was developed. Phenolic aldol condensation between 2-methylsesamol (15) and Garner's aldehyde provided the protected amino diol 16, which was converted to free amine 11 in excellent yield. A Pictet−Spengler reaction between 11 and ethyl glyoxylate under carefully controlled conditions
开发了一种高效合成含1,4-桥连的10元内酯的全功能四环(ABCH)7的方法。2-甲基芝麻酚(15)与Garner醛之间的酚醛羟醛缩合提供了受保护的氨基二醇16,该氨基二醇以优异的产率转化为游离胺11。在精心控制的条件下(LiCl,甲苯,1,1,1,3,3,3-六氟-2-丙醇,室温),11与乙醛酸乙酯之间的Pictet-Spengler反应提供了对酸敏感的四氢异喹啉(18)高收率转化为氨基醇9。甘氨酸模板的对映选择性烷基化在催化量的手性金鸡顿盐存在下是获得对映体纯氨基醛10的关键步骤。两个片段的联盟9和10经由中间恶唑烷,得到氨基腈39,其在与(伯醇的酯化- [R ) - ñ - (小号-4,4' ,4' “-trimethoxyltrityl)的Cys(42),得到43。43的环化反应(在三氟乙醇中为1%的三氟乙酸)通过多米诺骨牌工艺制得化合物44,该过程包括(a)脱除S-三甲氧基三苯甲