合成路线1

The condensation of 4-fluorobenzaldehyde (I) with ethyl acetoacetate (II) by means of piperidine, followed by a treatment with hot NaOH and esterification with methanol in acid medium, gives 3-(4-fluorophenyl)glutaric acid dimethyl ester (III), which is stereoselectively hydrolyzed with liver esterase in aqueous acetone, yielding the monoester (IV) with a 95% ee. The selective reduction of the ester group of (IV) with LiH and LiBH4 in THF affords the chiral 5-hydroxypentanoic acid (V), which is esterified with dimethyl sulfate in methanol to the corresponding methyl ester (VI). The reaction of (VI) with MsCl and TEA in toluene gives the mesylate (VII), which is cyclized with benzylamine (VIII) and TEA in toluene, affording the chiral piperidone (IX).The reaction of (IX) with dimethyl carbonate (X) and NaH in hot toluene yields the chiral carboxylate (XI), which is reduced at the carboxylate and ketonic groups with LiAlH4 or BH3 in DMSO, providing the chiral piperidine methanol derivative (XII). The reaction of (XII) with MsCl and TEA in toluene yields the mesylate (XIII), which is condensed with the phenol derivative (XIV) by means of NaH in hot DMF, affording the adduct (XV). Finally, this compound is debenzylated by hydrogenation with H2 over Pd/C.