The first asymmetric phase transfer catalysed alkylation reaction of a range of carbon acids with N-sulfonyl aziridines is reported. When 10 mol % os a cinchona derived quaternary ammonium salt was employed as the catalyst under mildly basic conditions N-o-(trifluromethane)benzenesulfonyl aziridine was efficiently ring-opened to afford the amino ethylene products in consistantly high yields and high enantioselectivities (up to 97%). By employing substituted aziridines in single enantiomeric form, the corresponding enantiopure alkylation products could be obtained with a range of pronucleophiled in high yields and moderate to high diastereoselectives (up to 30:1 dr).