A simple route to enantiopure bis-lactones: synthesis of both enantiomers of epi-nor-canadensolide, nor-canadensolide, and canadensolide
作者:Sujit Mondal、Subrata Ghosh
DOI:10.1016/j.tet.2008.01.009
日期:2008.3
A simple strategy has been developed for the synthesis of both enantiomers of nor-canadensolide, epi-nor-canadensolide, and an intermediate to canadensolide. An orthoester Claisen rearrangement of an appropriately constructed allyl alcohol derivative prepared from R-(+)-2,3-di-O-cyclohexylidine glyceraldehyde followed by epoxidation of the resulting unsaturated esters produced hydroxy-lactones, which
已经开发了一种简单的策略,用于合成降钙假固体的对映异构体,epi-降钙假固体的对映异构体和candendensolide的中间体。由R -(+)-2,3-二-O-环己基丙三醛甘油制得的适当构造的烯丙醇衍生物的原酸酯克莱森重排,然后环氧化所得的不饱和酯产生羟基内酯,其在氧化时得到酮内酯。使用螯合控制或非螯合控制的方法选择性立体还原酮羰基导致天然或epi系列。极性基团之间的电子效应与酮内酯还原过程中β取代基的空间效应之间的相互作用被证明是决定立体化学结果的关键因素。羟基内酯的缩酮部分中潜在的醛官能团的再生提供了内酯,该内酯在氧化时产生了双内酯。