Trifluoromethylthiolation/Selenolation and Lactonization of 2-Alkynylbenzoate: The Application of Benzyl Trifluoromethyl Sulfoxide/Selenium Sulfoxides as SCF 3 /SeCF 3 Reagents.

The combined use of BnS(O)CF 3 /BnSe(O)CF 3 with Tf 2 O as SCF 3 /SeCF 3 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 SCF 3 /SeCF 3 species via interrupted Pummerer reactions followed by a concerted trifluoromethylthiolation/selenolation and lactonization process.