Base-Controlled Diastereoselective Synthesis of Either anti- or syn-β-Aminonitriles

Deprotonation of secondary alkane nitriles with nBuLi and addition to aryl imines gives kinetic anti-β-aminonitriles. Use of LHMDS allows reversible protonation of the reaction intermediate to give syn-β-aminonitriles. The pure diastereosiomers can be isolated in good yields, and the mechanism was elucidated.