Surface photochemistry: the amide Photo-Fries rearrangement

The Photo-Fries rearrangement of eight anilides on the surface of dry silica gel has been examined. The rearrangement occurs quite cleanly, giving somewhat more of the para isomer than that obtained in methanolic solution. A test for intermolecularity on the silica gel surface showed that, as in solution, the radical pair intermediates do not separate. This contrasts with the behaviour of a previously reported dibenzyl ketone derivative.