作者:William R. Roush、Lance A. Pfeifer
DOI:10.1021/ol005629l
日期:2000.3.1
[formula: see text] The final stages of a total synthesis of mycalamide A are described. A key step is the aldol reaction (mismatched) of imide 4 and aldehyde 5 which provided a ca. 5:4 mixture of aldols 10a and 10b, with incorrect C(7) stereochemistry. Elaboration of the 10a-10b mixture to mycalamide A required epimerization of C(7) at the stage of beta-keto imide 11. Alternatively, Swern oxidation
[式:见正文]描述了全合成mycalamide A的最终阶段。关键步骤是酰亚胺4和醛5的醛醇缩合反应(不匹配),可提供约1-4的摩尔比。5:4醛醇10a和10b的混合物,具有错误的C(7)立体化学。将10a-10b混合物精细合成为Mycalamide A,需要在β-酮亚酰胺11阶段将C(7)差向异构化。或者,在最小化C(7)差向异构化的条件下Swern氧化10a-10b混合物导致7-表mycalamide A选择性。