An ene-ester 5 prepared from L-malic acid was subjected to the ester-enolate Claisen rearrangement under Ireland's condition to give stereoselectively C16–C22 fragment 11 containing (E) trisubstituted double bond which was further advanced to C1–C22 fragment 2 by sequential coupling with C10–C15 and C1-C9 fragments.
在爱尔兰的条件下,对由
L-苹果酸制得的烯酯5进行酯-烯酸酯克莱森重排,得到立体选择性的C16-C22片段11,该片段含有(E)三取代的双键,该片段进一步通过顺式作用前进至C1-C22片段2与C10–C15和C1-C9片段结合。