Quantum mechanical transition-state analysis reveals the precise origin of stereoselectivity in chiral quaternary cinchonidinium phase-transfer catalyzed enolate allylation.

Density functional theory was used to model glycinate enolate binding and enantiomeric allylation transition states mediated by the cinchonidinium phase-transfer catalyst 2. Transition states show oxy-anion-ammonium interactions in contrast to π-face interactions in the ground states. The details of stereoselectivity are described within the quaternary ammonium-tetrahedron face model.