Ring-closing olefin metathesis of acrylates derived from allylic and home allylic alcohols in the presence of the Grubbs' catalyst (10-15 mol%) and titanium isopropoxide (0.3-3 equiv) provided ready access to alpha, beta-unsaturated gamma- and delta-lactones and an important dipeptide isostere intermediate. (C) 1998 Elsevier Science Ltd. An rights reserved.