This paper describes a synthesis of 3-acyl-2-alkyl-3-ethoxycarbonylpropanoic acids from ethyl 2-oxoalkanoates and 2-bromoalkanoic acids. These acids are cyclised via intramolecular dehydration to give 2,4-dialkyl-3-ethoxycarbonyl-3-buten-4-olides or are condensed with allylzinc reagents to give the 4-alkenyl-2,4-dialkyl-3-ethoxycarbonyl-4-butanolides.