合成路线1

Horner-Emmons condensation of 2,3-isopropylidene-D-glyceraldehyde (I) with phosphonate (II) produced the unsaturated ester (IIIa-b). Ketal deprotection and lactone ring closure of (II) under acidic conditions, followed by O-silylation afforded (IV). The lactone function of (IV) was reduced with DIBAL and then with NaBH4-CeCl3 to produce the corresponding diol. Further silylation of the primary hydroxyl group furnished (V). Condensation of (V) with triethyl orthoacetate followed by Claisen rearrangement gave rise to the gamma,delta-unsaturated ester (VI). This was reduced to alcohol with LiAlH4 and then alkylated with benzyl bromide to yield benzyl ether (VII). Ozonization of (VII) in methanol at -78 C, followed by decomposition of the ozonide with dimethyl sulfide gave aldehyde (VIII). Horner-Emmons condensation of (VIII) with the sodium salt of triethyl phosphonoacetate (IX) produced the alpha,beta-unsaturated ester (X). Double bond hydrogenation in (X) with simultaneous benzyl group cleavage afforded hydroxy ester (XI), which was then converted to mesylate (XII). This was cyclized to the cyclopentane (XIIIa-b) by means of NaH in refluxing THF.