Catalytic Asymmetric Synthesis of Tertiary Alkyl Fluorides: Negishi Cross-Couplings of Racemic α,α-Dihaloketones

The development of new approaches to the construction of fluorine-containing target molecules is important for a variety of scientific disciplines, including medicinal chemistry. In this Article, we describe a method for the catalytic enantioselective synthesis of tertiary alkyl fluorides through Negishi reactions of racemic alpha-halo-alpha-fluoroketones, which represents the first catalytic asymmetric cross-coupling that employs geminal dihalides as electrophiles. Thus, selective reaction of a C-Br (or C-Cl) bond in the presence of a C-F bond can be achieved with the aid of a nickel/bis(oxazoline) catalyst. The products of the stereoconvergent cross-couplings, enantioenriched tertiary alpha-fluoroketones, can be converted into an array of interesting organofluorine compounds.