Chiral β-substituted γ-amino-butyric acids (GABAs) belong to a class of molecular architectures possessing a high pharmaceutical value. We report herein a straightforward efficient strategy to access such compounds by the Lewis acid-catalyzed asymmetric aminoalkylation reaction of ketene silyl acetals via enantioconvergent ring opening of racemic 2-(hetero)aryl-N-sulfonyl aziridines. This reaction features scalability, simple and commercially available catalysts, high enantioselectivities and mild reaction conditions with demonstrated utility in a two-step product transformation into the anti-inflammatory drug (R)-rolipram and its optical antipode.