Small-Ring Compounds. XXX. Reactions of Phenylcyclobutadienoquinone with Methanol

The thermal reaction of phenylcyclobutadienoquinone (I) with methanol gives 2,4-dimethoxy-3-phenylcyclobutenone The relative A possible mechanism is presented that accounts for the 2-hydroxy-2-methoxy-3-phenylcyclobutenon(IV). (II), 3-phenyl-4-hydroxy-4-methoxy-2-butenoiaccid lactone (III) and dimethyl phenylsuccinate (IV). The relative yields of the three products depend on the reaction temperature. A possible mechanism is presented that accounts for the formation of the three products by way of a common intermediate: 2-hydroxy-2-methoxy-3-phenylcyclobutenone (V). The structures of II and III were established by spectroscopic analysis, chemical degradation and independent synthesis.