Résumé : Di-n-butyl-, triphenyl and tri-n-butyltin derivatives of 3S,4S-3-[(R)-1-(tert-butyldimethyl-­silyloxy)ethyl-4-[(R)-1-carboxyethyl]-2-azetidi-­none were synthesized and characterized. Their antitumour activity was screened against seven tumoural cell lines of human origin. Copyright © 1999 John Wiley & Sons, Ltd.