Small-Ring Compounds. XVIII. Alkali-induced Ring Opening of Some Phenylcyclobutenone Derivatives

Phenylcyclobutenedione (I) has been found to decompose by the action of alkali to benzylidenepyruvic acid (X) and benzaldehyde. Similarly 2-hydroxy-3-phenyl-2-cyclobutenone (V) yields benzylpyruvic acid (VII), and 4-hydroxy-3-phenylcyclobutenedione (XI) gives phenylpyruvic acid (XII) and 1,3-diphenylpropene (XIII). Possible reaction mechanisms for the formation of these substances are proposed.