合成路线1

Compound (XV) is selectively acetylated with acetic anhydride and DMAP to the diol (XVI). The replacement of the benzyl protecting group by a triethylsilyl (TES) group in (XVI) by debenzylation with H2 over Pd(OH)2/C followed by treatment with TESCl in pyridine and deacetylation with K2CO3 in methanol affords the silylated triol (XVII). The formation of the oxetane ring is carried out by treatment of (XVII) with trimethylsilyl chloride (TMSCl) and pyridine (silylation of the primary alcohol), subsequent reaction with Tf2O (activation of the secondary alcohol), and cyclization by acidic treatment with CSA to give compound (XVIII) with the oxetane ring and a tertiary OH group. The acetylation of (XVIII) with acetic anhydride and DMAP affords compound (XIX) with the tertiary acetoxy group. The reaction of (XIX) with phenyllithium gives the benzoyloxy derivative (XX), which is oxidized with pyridinium chlorochromate (PCC) to yield the diketone (XXI). The reduction of (XXI) with NaBH4 in methanol affords compound (XXII) with the appropriate secondary hydroxy group, which is acylated with Ojima's beta-lactam (XXIII) by means of sodium bis(trimethylsilyl)amide to give the silylated paclitaxel (XXIV). Finally, this compound is deprotected with HF/pyridine.