Fluoromethyl Triflate and Fluoromethyl Fluorosulfonate: Easily Accessible and Powerful Fluoromethylation Reagents

Fluoromethyl triflate (superfluoromethyl, SFM, FH₂COSO₂CF₃) and fluoromethyl fluorosulfonate (magic fluoromethyl, MFM, FH₂COSO₂F) are two easily synthesized, highly effective and non-ozone depleting fluoromethylation reagents. They are analogous to the well-known and widely used methylation reagents H₃COSO₂CF₃ and H₃COSO₂F. Both SFM and MFM have been fully characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁷O, ¹⁹F, ³³S). Their structures have been determined in the solid state on in situ grown crystals by X-ray diffraction and in the gas phase by electron diffraction. The fluoromethylation efficiency of SFM and MFM was shown by reactions with chalcogen nucleophiles of differing nucleophilicity. All fluoromethylated products were isolated as pure compounds and characterized by NMR and vibrational spectroscopy, as well as in some cases by single crystal X-ray diffraction.