合成路线1

The chiral intermediate (1R,2S)-N-(tert-butoxycarbonyl)-2-fluorocyclopropylamine (III) can also be obtained as follows: 2) The cyclization of (1S,2R)-2-amino-1,2-diphenylethanol (XVII) with trichloromethyl chloroformate and triethylamine in dichloromethane gives (4R,5S)-4,5-diphenyloxazolidin-2-one (XVIII), which is treated with 1,1-dimethoxyethane and an acid catalyst, yielding the 1-methoxyethyl derivative (XIX). The heat treatment (150 C) of (XIX) affords the corresponding vinyl derivative (XX), which is cyclized with fluorodiiodomethane and diethyl zinc (a fluorocarbenoid compound) in a preferentially cis-way to afford the cyclopropyl-oxazolidinone (XXI), purified by column chromatography. The hydrogenolysis of (XXI) with H2 over Pd/C in acetic acid gives (1R,2S)-2-fluorocyclopropylamine (XXII), which is finally converted into (III) by reaction with tert-butoxycarbonyl anhydride and triethylamine in THF.