Enantiomerically pure α-substituted α-amino phenylacetonitriles have been readily prepared from 2-p-tolylsulfinylbenzaldimines following a two-step sequence: a moderately stereoselective hydrocyanationof the imines and a completely stereoselective quaternization of the resulting diastereoisomeric mixtureof α-amino phenylacetonitriles with different alkylating or acylating reagents in the presence of KHMDS.Theoretical calculations support a stereoselectivity control exerted by the remote sulfinyl group, as longas it is responsible for the conformational preferences of the benzyllithium intermediates, which sufferthe attack of the electrophiles to the less hindered diastereotopic face.