Two-photon processes in the photo-Claisen and photo-Fries rearrangements. Direct observation of dienic ketenes generated by photolysis of transient cyclohexa-2,4-dienones

Abstract

Using the two-laser two-colour technique it has been possible to promote two photon chemistry in the cases of benzyl phenyl ether 1a and phenyl acetate 1b; this is based on the photolysis of the transient cyclohexa-2,4-dienone intermediates 2a,b of the photo-Claisen and photo-Fries rearrangement to the dienic ketenes 4a and 4b.