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Significance: The strongly electron-withdrawing trifluoromethoxy group (OCF3) has attracted increasing attention as a unique substituent in biologically active compounds and organic materials; however, synthetic methods for installing OCF3 directly remain rare, due in part to the fact that many of the available sources of or precursors to the trifluoromethoxide anion (–OCF3) show limited stability or require specialized equipment for handling. Herein, the authors demonstrate the use of trifluoromethyl benzoate (TFBz) as a stable, liquid reagent for various direct trifluoromethoxylation reactions, acting as a precursor to–OCF3, which is generated in situ by treatment of TFBz with a fluoride salt.

Comment: The use of TFBz was showcased in the trifluoromethoxylation-bromination of arynes. Crown ether 1 and KF were the best combination to generate both the aryne intermediate and–OCF3 in situ, while several reagents …