合成路线1

Alternatively, the intermediate (Z)-ethylenic diol (XV) can also be obtained as follows: The reduction of 5,5-dimethyloxepan-2-one (XX) with iBu2AlH in THF gives 5,5-dimethyloxepan-2-ol (XXI), which is condensed with methyltriphenylphosphonium bromide (XXII) by means of tBu-OK in THF to yield 3,3-dimethyl-6-hepten-1-ol (XXIII). The Swern oxidation of the primary alcohol of (XIII) affords aldehyde (XXIV), which is condensed with CBr4 by means of PPh3 in CH2Cl2 to provide the dibromovinyl compound (XXV). The condensation of (XXV) with hexafluoroacetone (XII) by means of BuLi gives the acetylenic alcohol (XXVI), which is treated with hexylborane in THF to yield the acetylenic diol (XXVII). Finally, this compound is selectively reduced with H2 over Pd/C in EtOAc to afford the desired (Z)-ethylenic diol (XV).