合成路线1

The dihydroxylation of the farnesyl acetate (I) with Noe-Lin catalyst gives the dihydroxy compound (II), which is converted to the epoxide (III) by treatment first with mesyl chloride and pyridine, and then with K2CO3 in methanol. The reaction of (III) with mesyl chloride and LiBr in THF yields the bromide (IV), which is condensed with the silylated amine (V) by means of LDA in AcOH / NaOAc affording the epoxidized acyl silane (VI). The condensation of (VI) with isopropenyllithium (VII) and the cyclohexenylmethyl bromide (VIII) by means of BaI2 in THF gives the precursor (IX), which is cyclized by means of MeAlCl2 and protected with TBDMS-Cl in dichloromethane yielding the tricyclic ketone (X). The reaction of (X) with Tf2N-Ph affords the enol triflate (XI), which is further cyclized by means of Me3Sn-SnMe3 and palladium tetrakis(triphenylphosphine) in refluxing THF giving the silylated pentacyclic alcohol (XII), which is desilylated with TBAF in THF affording the pentacyclic alcohol (XIII). The benzoylation of (XIII) with benzoyl chloride gives benzoate (XIV), which is selectively methylenated with CH2I2 and Br2Zn in toluene yielding the cyclopropanated compound (XV).