Alkylation of diethyl malonate (II) with 5-(4-chlorophenyl)pentyl bromide (I) gives diethyl 5-(4-chlorophenyl)pentyl malonate (III). Intermediate (III) is hydrolyzed to the monoester (IV), followed by condensation with paraformaldehyde in pyridine/piperidine to yield ethyl 7-(4-chlorophenyl)-2-methyleneheptanoate (V), which is oxidized with m-chloroperbenzoic acid. Alternatively, intermediate (IV) can be prepared by condensation of 4-chlorocinnamaldehyde (VI) with diethyl ethylidenemalonate (VII) to yield intermediate (VIII) and subsequent hydrogenation.