Photo-Fries rearrangement 1-naphthyl esters

Cui and Weiss reported the photo-Fries rearrangements of 2-naphthyl myristate and 2-naphthyl acetate (Fig. 35) in unstretched and stretched low-density polyethylene films [116]. It was argued that the radical pair generated by irradiation is held in a cavity shaped like the starting ester and whose walls relax more slowly than the radicals recombine. The preferred solution product is too different in shape from the starting ester to be formed. 

Another example of the effect of confined medium is found during photo-Fries rearrangement of naphthyl esters in zeolites [103,104]. Upon photolysis in isotropic solution 1-naphthyl benzoate undergoes the photo-Fries rearrangement to yield both ortho (2-) and para (4-) phenolic ketones (Sch. 4). When this ester is included in NaY zeolite and irradiated the main product (96%) is the ortho isomer. This remarkable ortho-selectivity within zeolites has been rationalized on the basis of interactions of the reactant 1-naphthyl benzoate and intermediate radicals with the sodium ion. Due to restrictions imposed by the medium the benzoyl radical, once formed, is compelled to react only with the accessible ortho position. 

Further detailed studies confirm the impressive role played by the support in the photo-Fries rearrangement of 1-naphthyl esters. Indeed, l-hydroxy-2-acylnaphthols are obtained in 93%-99% yield upon irradiation (>300 nm) of different naphthyl esters adsorbed on LiY, NaY, and KY. 

The archetypal photochemical lateral-nuclear rearrangement in aromatic compounds is the photo-Fries rearrangement, and a relatively simple example is reported in which /Mjhlorophenyl salicylate (189) gives 5-chloro-2,2 -dihydroxybenzophenone. Use is made of the photo-Fries rearrangertient of 1-naphthyl esters (190) in the regioselective synthesis of tricyclic analogues of... 

Serum albumins have been employed as hosts for the photo-Fries rearrangement of 4-methoxy-l-naphthyl esters, at site I (acetate) and site II (monoglutarate) of the proteins. A species- and site-dependent quantum yield of product formation is observed the best results are obtained within site I of bovine serum albumin. ... 

Gu, W. Q., Bi, S. G., and Weiss, R. G., Photo-Fries rearrangements of 1-naphthyl esters in the glassy and melted states of poly(vinyl acetate). Comparisons with reactions in less polar polymers and low-viscosity solvents, Photochem. PhotobioL Sci., 1, 52, 2002. 

Photodecarboxylation in the presence of photocatalysts such as TiOj has also been studied. For example, the photodegradation of (4-chloro-2-methylphenoxy)acetic acid, a herbicide, in an aqueous solution of TiOj involves elimination of carbon dioxide from the initially formed radical species on the catalyst surface. The templating of carboxyHc acids with polyethylene films has been found to enhance the photodecarboxylation at the expense of the photo-Fries rearrangement in simple aryl esters such as phenyl and 1-naphthyl esters." ... 

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