Asymmetric Fluorination of Enamides: Access to α-Fluoroimines Using an Anionic Chiral Phase-Transfer Catalyst

The use of a BINOL-derived phosphate as a chiral anionic
phase-transfer
catalyst in a nonpolar solvent allows the enantioselective fluorination
of enamides using Selectfluor as the fluorinating reagent. We demonstrate
that a wide range of stable and synthetically versatile α-(fluoro)­benzoylimines
can be readily accessed with high enantioselectivity. These compounds
have the potential to be readily elaborated into a range of highly
stereodefined β-fluoroamines, compounds that constitute highly
valuable building blocks of particular importance in the synthesis
of pharmaceuticals.