The Chemistry of Phthalide-3-carboxylic Acid. II. Decarboxylation of Salts in the Presence of Aldehydes

Salts of phthalide-3-carboxylic acid decarboxylate in the presence of aromatic aldehydes to give mixtures of the 3-( arylhydroxymethyl ) phthalide (2) and the 2-aryl-3-hydroxyindenone (3). The former may be obtained exclusively in the presence of the weak proton donor, triethyl (2-phenylethyl)ammonium chloride, and the latter in the presence of crown ethers or after longer reaction times. A study of the effect of different cations allows a mechanism to be deduced.