Enantio- and Diastereoselective Catalytic Mannich-Type Reaction of a Glycine Schiff Base Using a Chiral Two-Center Phase-Transfer Catalyst

Optically active α,β‐diamino acids are prepared under asymmetric phase‐transfer reaction conditions from a glycine Schiff base and N‐protected imines with a tartrate‐derived diammonium salt (TaDiAS) as the phase‐transfer catalyst (see scheme; Boc=tert‐butoxycarbonyl). Chemoselective deprotection of the N atoms allows straightforward transformations of the α,β‐diamino acid products to be carried out.