Synthesis of cis-2-Fluorocyclopropylamine by Stereoselective Cyclopropanation Under Phase-transfer Conditions

cis-2-Fluorocyclopropylamine is stereoselectively synthesized by cyclopropanation of 3-aryl-2-vinyl-3-(methoxy)isoindol-1-one by treating dibromofluoromethane with saturated aqueous KOH solution in the presence of 18-crown-6 in dichloromethane, followed by removal of a bromine atom of the formed bromofluorocyclopropane derivative with Raney Ni, and successive three steps-deprotection procedures for generating an amino group on the cyclopropane ring.