The cycloaddition of ketene to methyl, ethyl, isopropyl and n-butyl glyoxylates resulting from the scission of corresponding tartrate diesters has been used to prepare racemic 4-alkyloxycarbonyl 2-oxetanones. The reaction was conducted in dichloromethane at low temperature in the presence of triethylamine as catalyst. The use of a chiral tertiary amine instead of triethylamine yielded an optically active β-lactone as shown in the case of methyl glyoxylate. The maximum enantiomeric excess was about 70 per cent and the sign of the elected enantiomer depended on the chiral base. Racemic n-butyl malolactonate was homopolymerized and copolymerized with benzyl malolactonate. High molecular weight polymers resulting from the homopolymerization of n-butyl malolactonate or from the copolymerization of this monomer with benzyl malolactonate were characterized by SEC and NMR. The ketene route was also used to synthesize racemic 4-trichloroethyloxycarbonyl 2-oxetanone, a β-substituted β-lactone, which had never been synthesized by other routes.