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

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