Asymmetric synthesis of the northern segment of ephedradine C. A novel dihydrobenzo[b]furan formation
作者:Michael G.N. Russell、Raymond Baker、JoséL. Castro
DOI:10.1016/s0040-4039(99)01835-3
日期:1999.12
An asymmetric synthesis of the dihydrobenzo[b]furan segment of ephedradine C has been achieved utilising a chiral oxazolidinone in an aldol reaction to form a β-hydroxy ester, followed by a novel debenzylation and concomitant intramolecular cyclisation with iodotrimethylsilane as key steps. An asymmetric Michael reaction with a homochiral lithium amide was used to form the third and final chiral centre
利用手性恶唑烷酮在醛醇缩合反应中形成β-羟基酯,然后进行新型的脱苄基反应和伴随的分子内环化反应,以碘代三甲基硅烷为关键步骤,实现了麻黄碱C的二氢苯并[ b ]呋喃链段的不对称合成。与同手性锂酰胺的不对称迈克尔反应用于形成第三个也是最后一个手性中心。