合成路线1

Horner-Emmons condensation of 3,3'-difluorobenzophenone (I) with diethyl (cyanomethyl)phosphonate provided 3,3-bis(3-fluorophenyl)acrylonitrile (II). The olefinic double bond of (II) was then reduced using catalytic hydrogenation to give (III). After deprotonation of (III) with either lithium diisopropylamide or lithium hexamethyldisilazide at -78 C, alkylation with iodomethane afforded the racemic alpha-methyl nitrile (IV). Isolation of the required (R)-enantiomer (V) was accomplished by means of chiral HPLC. Finally, reduction of the nitrile group of (V) with borane-dimethyl sulfide complex provided the title amine, which was isolated as the hydrochloride salt.