Addition of vinylmagnesium bromide to diisopropyl ketone (I) produced carbinol (II). Subsequent oxidation of (II) with pyridinium chlorochromate gave unsaturated aldehyde (III), which was further hydrogenated to the saturated aldehyde (IV). Optionally, oxidation with sodium chlorite produced carboxylic acid (V), which was converted to acid chloride (VI) using oxalyl chloride and pyridine.

Aldol condensation of silylated lactone (VII) with aldehyde (IV) gave hydroxy lactone (VIII). Subsequent hydroxyl group mesylation followed by elimination in the presence of DBU generated alkylidene lactone (IXa-b) as a mixture of geometric isomers, which were separated by chromatography. Desilylation of (IX) to afford diol (X) was achieved by means of HF/pyridine. Finally, monoacylation of (X) with acid chloride (VI) and pyridine furnished the target ester.