Cyclization Pathways of a (Z)-Stilbene-Derived Bis(orthoquinone monoketal)

Lead tetraacetate mediated oxidation of a (Z)-bisphenolic stilbene derivative affords a bis(orthoquinone monoketal) product. Thermolysis studies of this highly unsaturated dione reveal that sigmatropic hydrogen shifts, followed by either of two distinct solvolytic ring closures, constitute the predominate reaction pathways under heating. No evidence for a desired 6π electron electrocyclization was forthcoming.