Prephenic Acid: Properties and the Present Status of its Synthesis

Prephenic acid is an intermediate in the biosynthesis of aromatic compounds. Its synthesis is made difficult by the fact that it is a cyclohexadienol which is easily aromatized by acids and bases. Experiments aimed at its synthesis have led to an as yet inseparable mixture of a little prephenic acid, epiprephenic acid and dihydroprephenic acid (as‐Ba‐salt). Comparison with model compounds indicated that the tertiary carboxyl group and the hydroxyl group are in cis relationship.