Simple practical synthesis of 3,3-difluoropyrrolidine from 2,2-dichlorotrifluoro-1-iodoethane

Novel simple approach was elaborated for the preparation of 3,3-difluoropyrrolidine hydrochloride starting from commercially available technical 2,2-dichlorotrifluoro-1-iodoethane. Its radical addition to ethylene afforded the corresponding iodide that was transformed into the primary amine. The last one was heated with sodium hydrosulfide to form previously unknown 3,3-difluoropyrrolidine-2-thione which was converted into the target product in high yield. The whole transformation does not require the use of toxic, flammable, explosive and hazardous reagents as well as column chromatography purification. Alternative syntheses have been proposed for the intermediate and target compounds.