合成路线1

Michael addition of methyl acrylate (XII) to (3,4-dichlorophenyl)acetonitrile (XI) produced the cyano diester adduct (XIII). Catalytic hydrogenation of the cyano group of (XIII) over Raney nickel with concomitant intramolecular cyclization gave rise to the piperidinone (XIV). After basic hydrolysis of the methyl ester function of (XIV), the resultant piperidone propionic acid (XV) was reduced to piperidino alcohol (XVI) by means of borane in THF. Resolution of the racemic piperidine (XVI) employing (+)-camphorsulfonic acid provided the dextro enantiomer (XVII). After N-protection of (XVII) as the Boc derivative (XVIII), its primary alcohol was activated as the corresponding mesylate (XIX) with methanesulfonyl chloride and Et3N. Condensation between mesylate (XIX) and intermediate piperidine (X) in acetonitrile at 60 C, produced (XX). The title benzamido derivative was then obtained by acid-promoted Boc group cleavage in (XX), followed by acylation with benzoyl chloride.