synthesis of (+)-ivalin (4), a representative of antileukemic eudesmane sesquiterpenes, is described. The ene-aldehyde (6) was converted to the nearly optically pure alcohol (20) through the asymmetric double a1ky1ation reaction of the chiral ene-enamine (14). The ene-carbonyl cyclization of (25) with tin(IV) chloride afforded the core skeleton (26). The stereoinversion of hydroxyl group and further transformation
描述了不对称全合成的(+)-艾维林(4),是抗泛素的杜仲
倍半萜烯的代表。通过手性
烯-
烯胺(14)的不对称双烷基化反应,将
烯醛(6)转化为几乎光学纯的醇(20)。用
氯化锡(IV)对(25)进行
烯-羰基环化,得到核心骨架(26)。羟基的立体转化和进一步的转化提供了(+)-艾维林(4)。