SENSITIZED PHOTOLYSIS OF BENZOYL AZIDE. A NITRENE SINGLET-TRIPLET EQUILIBRIUM
The acetophenone-sensitized photolyses of benzoyl azide in cis-and trans-1,4-dimethylcyclohexanes gave the N-substituted benzamides stereospecifically. The photolyses in 2,3-dimethylbutane showed the same insertion regioselectivity ratio toward the C–H bonds as that of singlet benzoylnitrene in the direct photolysis. These facts indicate the existence of the singlet nitrene despite the triplet photosensitization and provide a chemical evidence for the establishment of a singlet-triplet equilibrium for benzoylnitrene.