Facile autoxidation of 2-(4-hydroxyphenyl)-3,3-dimethylmethylenecyclopropane. The radical stabilizing ability of the phenoxide group

2-(4-Hydroxyphenyl)-3,3-dimethylmethylenecyclopropane undergoes rapid react ion with O-2 at room temperature to give a dioxolane, A chain mechanism inv olving ring opening of a phenoxy radical is proposed. Conversion of the tit le compound to the phenoxide results in a remarkably accelerated methylenec yclopropane rearrangement. Computational studies suggest that the intermedi ate biradical is greatly stabilized by the phenoxide substituent.