合成路线1

Condensation of benzaldehyde (XXVI) with ethyl glycinate hydrochloride (XXVII) by means of Na2SO4 and Et3N in tert-butyl methyl ether gives 2-(benzylideneamino)acetic acid ethyl ester (XXVIII), which cyclizes with 1,4-dibromo-2(E)-butene (XXIX) in the presence of t-BuOLi in dry toluene to yield, after imine hydrolysis, the cyclopropylamine derivative (XXX). Protection of amine (XXX) with Boc2O furnishes the racemic N-Boc amino ester (XXXI), which is subjected to kinetic resolution by means of enzymes such as Acalase®, Savinase® or Esperase® in DMSO to afford unreacted (1R,2S)-isomer (XXXII). Saponification of ethyl ester (XXXII) using LiOH in THF/MeOH gives the cyclopropanecarboxylic acid derivative (XXXIII), which, after activation with CDI in refluxing THF, is coupled with cyclopropanesulfonamide (XXXIV) (prepared by treatment of cyclopropanesulfonyl chloride [XXXV] with NH3 in THF) in the presence of DBU to yield the N-acylsulfonamide (XXXVI). Alternatively, the sulfonamide intermediate (XXXIV) can be prepared by condensation of 3-chloropropanesulfonyl chloride (XXXVIII) with tert-butylamine in THF to give N-tert-butyl-(3-chloro)propylsulfonamide (XXXIX), which then cyclizes to the cyclopropyl derivative (XL) by treatment with n-BuLi in THF at –78 °C. Removal of the N-tert-butyl group in intermediate (XL) using CF3CO2H then furnishes cyclopropanesulfonamide (XXXIV). After N-Boc group cleavage in (XXXVI) by means of CF3CO2H in DCM, acidification with HCl in Et2O affords intermediate (IV) . Intermediate (VIII) can be obtained by vinyl group reduction in (IV) with H2 and Pd/C in EtOAc. Intermediate (VIII) can also be obtained by reduction of vinylcyclopropylamine derivative (XXXVI) with H2 over Ru/C in MeOH to yield N-Boc-ethylcyclopropylamine (XXXVII), which is finally N-deprotected by means of HCl in CH2Cl2 .