1,3-Dipolar cycloadditions of the nitrone 1 to alpha,beta-unsaturated delta-lactones: non-chiral 13, racemic mixture 3/4, D-glycero 3, and L-glycero 4 proceed with high stereoselectivity in the cases of 13 and 3 and a significant kinetic resolution in the case of the racemate 3/4. The exo approach to the re-re sides of the lactones predominates. (C) 2000 Elsevier Science Ltd. All rights reserved.