Aldimines of a-amino esters derived from aldehydes bearing an alpha-, beta- or gamma-protected amino group undergo AgOAc/R3N catalysed cycloaddition to electronegative olefins (dipolarophile). Subsequent unmasking of the amino group and lactamisation, spontaneous in most cases, generates 5-7 membered fused and bridged bi- and tri-cyclic lactams. The regioselectivity of the lactamisation is controlled by appropriate choice of the dipolarophile. (C) 2002 Elsevier Science Ltd. All rights reserved.