合成路线1

Taxane intermediates (XIII) and (XIV) were prepared by two related ways. Wittig condensation of cyclopropanecarboxaldehyde (I) with methoxycarbonylmethylenetriphenyl phosphorane (II) gave methyl trans-cyclopropylacrylate (III). This was oxidized with potassium ferricyanide in the presence of OsO4 and the chiral catalyst 1,4-bis(9-O-dihydroquinidyl)phthalazine to furnish (2S,3R)-diol (IV). After conversion of (IV) to tosylate (V), its cyclization by means of K2CO3 produced epoxide (VI). Subsequent epoxide opening with NaN3 gave azide (VII), which was hydrogenated in the presence of Pd/C and di tert-butyl dicarbonate to furnish carbamate (VIII). Treatment of (VIII) with isopropenyl methyl ether (IX) and pyridinium tosylate, followed by ester hydrolysis, produced oxazolidine (X). This was coupled to protected taxane (XI) by means of DCC and DMAP to provide ester (XII). Oxazolidine hydrolysis in (XII) with formic acid, followed by reprotection of the amine with Boc2O, furnished intermediate (XIII). Optionally, the trichloroethoxycarbonyl groups of (XIII) were removed upon treatment with Zn and AcOH to produce intermediate (XIV).