Isolation of Cyclohexadienone Intermediates in the Photo-Fries Rearrangement of 2,4Dimethylnaphth-1-yl and 1,4-Dimethylnaphth-2-yl 2,4,6-Trimethylbenzoates

Labile cyclohexadienones were isolated for the first time in good yields in the photo-Fries rearrangement of partially blocked naphthyl esters. Upon direct excitation at 313 nm, 1,4-dimethylnaphth-2-yl and 2,4-dimethylnaphth-1-yl 2,4,6trimethylbenzoates afforded 1-acyl-2-naphthalenone and 2- and 4-acyl-1-naphthalenones, respectively. This isolation is of particular importance as a direct mechanistic proof and also as a convenient route to these thermally less-accessible compounds.