Stabilization of ortho-quinone methides by a bis(sulfonium ylide) derived from 2,5-dihydroxy-[1,4]benzoquinone

The zwitterionic intermediates (2a) in the oxidation of ortho-methylphenols (1) and bis(sulfonium ylide) 3 form reasonably stable 2:1-complexes (4) which can be synthetically used as 'stabilized ortho-quinone methides'.