Copper‐Catalyzed Trifluoromethylation and Cyclization of Aromatic‐Sulfonyl‐Group‐Tethered Alkenes for the Construction of 1,2‐Benzothiazinane Dioxide Type Compounds

A multi-talented system: An efficient copper-catalyzed tandem trifluoromethylation/annulation of an electron-deficient aromatic ring has been developed. This method provides a powerful and straightforward way to synthesize trifluoromethylated 1,2-benzothiazinane dioxides under mild conditions (see scheme). The mechanism was investigated by a series of kinetic experiments and isotopic labeling studies.