Tridentate chiral amines 7-13 mediated the asymmetric condensation reaction of lithium ester enolate 2 with benzaldehyde p-anisidine imine 3 giving the corresponding beta-lactam 4 in UP to 75% ee. It became apparent that coexistence of 2 and chiral lithium amides derived from 7-13 is an important factor for the enhancement of the reactivity and enantioselectivity of 2. (C) 1999 Elsevier Science Ltd. All rights reserved.