The present invention relates to a method for producing novel 4-[1-oxoalkyl]-2,5-oxazolidinediones, (4-1 OOD), and their use in a stereoselective method of producing beta-lactam-containing compounds which include several biologically active compounds such as the well-known families of pencillin and cephalosporin antibiotics. The method of the present invention involves generally the reaction of the above-described 4-[1-oxoalkyl]-2,5-oxazolidinediones so produced with a thiol amine having a geometry amenable to forming the precursor of the desired beta-lactam-containing compound or, in one scheme, forming the beta-lactam-containing compound itelf directly. This is done either by direct reaction of the 4-1 ODD with a thiol amine (which by one pathway proceeds directly to the beta-lactam-containing compound) or by first converting the 4-1 OOD to its 2-[1-oxoalkyl]-2-amino acid form before its reaction with the thiol amine; and then forming the beta lactam by action of cyanogen). The beta-lactam-containing compounds can be further modified according to methods known in the art to produce specific derivatives as desired.