Silver-Mediated Oxidative Decarboxylative Trifluoromethylthiolation of Coumarin-3-carboxylic Acids

The
introduction of trifluoromethylthio groups into organic compounds,
in particular heterocycles, is important because of the prevalence
of these structures in medicinally and agriculturally relevant molecules.
Herein, the silver-mediated oxidative decarboxylative trifluoromethylthiolation
of coumarin-3-carboxylic acids is reported. This methodology utilizes
existing carboxylic acid functionalities for the direct conversion
to CF3S groups and results in a broad scope of 3-trifluoromethylthiolated
coumarins, including analogues of natural products, in moderate to
excellent yields.