合成路线1

The condensation of aldehyde (XXVII) with phosphorane (XVIII) in refluxing THF gives the triunsaturated ester (XXVIII), which is reduced with DIBAL in dichloromethane to yield the primary alcohol (XXIX), which is oxidized with TPAP and NMO, affording the aldehyde (XXX). Further oxidation of (XXX) with NaClO2 in tert-butanol/water provides the carboxylic acid (XXXI), which is esterified with the chiral alcohol (XXXII) by means of DCC and DMAP in refluxing dichloromethane to give the ester (XXXIII). Elimination of the silyl protecting groups of (XXXIII) with HCl in THF yields the dihydroxy compound (XXXIV). Oxidation of the secondary and primary OH groups of (XXXIV) with DMP and NaClO2 affords the corresponding oxo acid (XXXV), which is finally treated with BCl3 in dichloromethane to eliminate the Pmb protecting groups and afford the target compound.