Catalytic transformations of alpha-amino C-H bonds to afford valuable enantiomerically enriched alpha-substituted amines, entities that are prevalent in pharmaceuticals and bioactive natural products, have been developed. Typically, such processes are carried out under oxidative conditions and require precious metal-based catalysts. Here, we disclose a strategy for an enantioselective union of N-alkylamines and alpha,beta-unsaturated compounds, performed under redox-neutral conditions, and promoted through concerted action of seemingly competitive Lewis acids, B(C6F5)(3), and a chiral Mg-PyBOX complex. Thus, a wide variety of beta-amino carbonyl compounds may be synthesized, with complete atom economy, through stereoselective reaction of an in situ-generated enantiomerically enriched Mg-enolate and an appropriate electrophile.