Controllable Selective Functionalization of a Cavitand via Solid State Photolysis of an Encapsulated Phenyl Azide

Phenyl azide (1) has been encapsulated within cavitand 2 to form a 1:1 complex of 1@2 in the solid state. Subsequent irradiation affords two diastereomeric nitrene addition products 5 and 7. The ratio of 5 and 7 can be reversed by thermally induced valence isomerization to 1H-azepine 8 followed by photolysis. In sharp contrast, phenylnitrene generation by photolysis of the corresponding 1.5:1 complex results mainly in the regioselective formation of C−H insertion product 4. The supramolecular approach to phenylnitrene chemistry provides good yields, in contrast to the generally low yield reactions of this species in solution.