Synthesis of β-Fluorovinyliodonium Salts by the Reaction of Alkynes with Hypervalent Iodine/HF Reagents.

The reaction of alkynes with PhIO and Py center dot HF followed by treatment with BF3 center dot OEt2 gave beta-fluorovinyliodonium tetrafluoroborates in good to high yields. More conveniently, the reaction using PhI and Py center dot HF in the presence of m-CPBA also afforded beta-fluorovinyliodonium tetrafluoroborates in good yields. These methods have the advantages that beta-fluorovinyliodonium salts can be prepared without ArIF2.