Application of the Photo‐Fries Reaction as a Key Step in the Preparation of Valuable Aryloxyethyl Selenocyanates

Abstract A multistep sequence leads to the preparation of a series of aryl selenocyanate WC‐9 homologues, which are interesting compounds with potential biological activity against Trypanosoma cruzi , the etiological agent of Chagas disease. The synthetic sequence involves the application of the photo‐Fries rearrangement reaction as a key step for the preparation of a series of 2‐hydroxyphenones bearing alkyl chains of different length and a phenyl group. These intermediates are obtained upon direct irradiation (254 nm) of 4‐phenoxyphenyl esters in different solvents at room temperature. Then, reaction of the 2‐hydroxyphenones with 2‐(2‐bromoethoxy)tetrahydro‐2 H ‐pyran followed by acid deprotection, tosylation (or mesylation) reaction and, finally, nucleophilic attack with potassium selenocyanate provides the target aryloxyethyl selenocyanate homologues in good yields.