Darzen抯 condensation of 4,4'-dichlorobenzophenone (I) with ethyl chloroacetate (II) produced the glycidic ester (III), which was subsequently converted to aldehyde (IV) upon treatment with KOH. Diol (V) was then obtained by Tollens?reaction of aldehyde (IV) with formaldehyde. Ethyl 4-chlorophenylglyoxylate (VII) was prepared by addition of the Grignard reagent prepared from 1-bromo-4-chlorobenzene (VI) to diethyl oxalate. The condensation between diol (V) and keto ester (VII) in the presence of boron trifluoride furnished the cyclic ketal (VIII). Finally, saponification of the ethyl ester group gave rise to the target carboxylic acid.