Intramolecular Alkene Fluoroarylation of Phenolic Ethers Enabled by Electrochemically Generated Iodane.

The 3-substituted chromane core is found in several bioactive natural products. Herein, we describe a route to 3-fluorinated chromanes from allylic phenol ethers. Our external oxidant-free approach takes advantage of an electrochemical generation of a hypervalent iodine species, difluoro-λ-tolyl iodane, which mediates the alkene fluoroarylation. High yields and selectivity for this transformation are achieved for electron poor substrates. The redox chemistry has been characterized for the electrochemical generation of the iodane in the presence of fluoride, and insights into the mechanism are given. The transformation has been demonstrated on gram scales, which indicates the potential broader utility of the process.