Trifluoromethylthiolation/Selenolation and Lactonization of 2-Alkynylbenzoate: The Application of Benzyl Trifluoromethyl Sulfoxide/Selenium Sulfoxides as SCF3/SeCF3 Reagents.

The combined use of BnS(O)CF3/BnSe(O)CF3 with Tf2O as SCF3/SeCF3 reagents was implemented to realize an efficient synthesis of biologically interesting 4-(trifluoromethylthio/trifluoromethylseleno)isocoumarins from 2-alkynylbenzoates. The mechanistic pathway was postulated to involve formation of the electrophilic SCF3/SeCF3 species via interrupted Pummerer reactions followed by a concerted trifluoromethylthiolation/selenolation and lactonization process.