合成路线1

In a further procedure, nitrile (XXIII) was alkylated with ethyl 3-bromopropionate (XXVIII) to give cyano ester (XXIX). Catalytic hydrogenation of the cyano group of (XXIX) gave rise to the piperidinone (XXX), which was further reduced to piperidine (XXXI) with LiAlH4 in THF. Acid deprotection of the tetrahydropyranyl group of (XXXI), followed by resolution with (+)-camphorsulfonic acid, furnished the desired (S)-piperidinoalcohol camphorsulfonate salt (XXXII). Treatment of piperidine (XXXII) with benzoyl chloride in the presence of DIEA yielded benzamide (XXXIII). Conversion of the primary alcohol of (XXXIII) into the desired alkyl iodide (XXXV) was achieved via formation of the mesylate ester (XXXIV), followed by displacement of the mesylate group with KI in refluxing acetone.