10.1021/acs.orglett.1c01720
The study presents an efficient method for the trifluoromethylation of benzoic acids using TMSCF3 (trimethylsilyl trifluoromethane) to produce aryl trifluoromethyl ketones. The reaction involves anhydrides as in situ activating reagents, with trifluoroacetic anhydride (TFAA) and 4-dimethylaminopyridine (DMAP) playing crucial roles in activating the carboxylic acids and facilitating nucleophilic addition. CsF (cesium fluoride) is used to enhance the yield of the desired products. The reaction is conducted in PhOMe (anisole) solvent under nitrogen at 120 °C for 15 hours. The study demonstrates a wide substrate scope, including various carboxylic acids with different functional groups, and shows high functional group tolerance. Notably, bioactive molecules such as adapalin, probenecid, and telmisartan can also be trifluoromethylated using this method, highlighting its potential in drug design and development. The reaction conditions are relatively mild, and the process is scalable, making it a practical and environmentally benign approach for synthesizing aryl trifluoromethyl ketones.