合成路线1

In a different procedure, 3,4-dichlorophenylacetic acid (XIV) was condensed with the lithiated chiral oxazolidinone (XV), via activation as the mixed anhydride with pivaloyl chloride, to afford the N-acyl oxazolidinone (XVI). Diastereoselective alkylation of the sodium enolate of (XVI) with allyl iodide (XVII) afforded the (S)-pentenyl oxazolidinone (XVIII), which was further hydrolyzed to the chiral acid (XIX) by means of lithium peroxide. Alternatively, acid (XIX) was obtained by alkylation of the lithium dianion of 3,4-dichlorophenylacetic acid (XIV) with allyl bromide (XX), followed by resolution of the resultant racemic acid (XXI) with (S)-1-phenylethylamine. Acid (XIX) was converted to the amide (XXII) via the corresponding acid chloride. Reduction of amide (XXII) with DIBAL gave the secondary amine (XXIII), which was subsequently acylated with benzoyl chloride, yielding benzamide (XXIV). Dihydroxylation of the olefin double bond with N-methylmorpholine-N-oxide in the presence of OsO4, followed by oxidative cleavage of the resultant diol (XXV) with sodium periodate furnished aldehyde (XXVI). Finally, reductive amination of aldehyde (XXVI) with piperidine (III) in the presence of NaBH3CN provided the title compound