REACTIVITIES OF NITRENES GENERATED BY PHOTOLYSIS OF 2-(OMEGA-PHENYLALKYL)PHENYL AZIDES

摘要

In order to investigate the reactivity of a photolytically generated arylnitrene with an intramolecular CH bond, the photochemistry of 2-(omega-phenylalkyl)phenyl azides (1a-d) was examined. Irradiation of 1 in solution revealed that the insertion of the nitrene into an adjacent CH bond to give cyclic compounds 4 and 5 occurs favorably only when a reactive CH bond, such as benzylic, is located close to the nitrenic center. This process can compete with the formation of products derived from triplet nitrene, but not with the capture of didehydroazepine by DEA. On the other hand, irradiation of 1b in an Ar matrix at 12 K gave a mixture of the CH insertion product 4b and the didehydroazepine 15. The origin of the difference in reactivity of the nitrene observed in solutions and in a matrix, and the spin state of the nitrene involved in the CH insertion reaction, are discussed. [References: 60]