Attempted Synthesis of a Stable, Quintet, Tetraphenoxyl Tetraradical:  Facile Rearrangement of a Substituted Bicyclobutane

The preparation of tetraphenol <b>3</b> and its attempted oxidation to tetraradical <b>2</b> are described. Tetraphenoxyl <b>2</b> was envisioned as a more stable analog of the previously reported, quintet tetraradical <b>1</b>. However, EPR studies on <b>3</b> and model compounds and crystallographic characterization of the product from oxidation of <b>3</b> suggest that <b>2</b> is not a viable target. Apparently, <b>2</b> or an intermediate in the multistep oxidation path leading to it undergoes a ring closure to a bicyclobutane. The bicyclobutane, in turn, undergoes a surprisingly facile rearrangement to the analogous butadiene structure.