A Spectroscopic and Computational Study of a Photoinduced Cross‐Dehydrogenative Coupling Reaction of a Stable Semiquinone Radical

Norrish‐type‐II reaction on a semiquinone radical : Stable semiquinone radicals serve as novel molecular platforms on which a Norrish‐type‐II photoreaction can be initiated. A detailed reaction scheme involving a 1,5‐hydrogen transfer followed by a cyclization step that finally leads to a new CC bond formation could be verified. Transient absorption spectroscopy and DFT calculations trace convincingly the intermediates and transition states along the reaction path (see scheme).