Divergent Regio- and Stereoselective Gold-catalyzed Synthesis of α-Fluorosulfones and β-Fluorovinylsulfones from Alkynylsulfones.

We developed a widely applicable, highly efficient synthesis of α-fluorosulfone and β-fluorovinylsulfone catalyzed by gold. Starting with alkynyl sulfone 1, an [Au]/HF/N-oxide system gives α-fluorosulfone 3 via a gold carbene intermediate, and, if no N-oxide is used, direct addition of HF to 1 gives vinyl sulfone 4 via a vinylfluoro gold intermediate. Both methods have good functional group tolerance and the reactions can be conducted in ambient atmosphere.