Fluorine as a Control Element in Asymmetric Synthesis

The installation of fluorine atoms in reactants or catalysts has a dramatic impact on reactivity, regioselectivity and stereoselectivity. Several effects account for the modified stereochemical outcome of reactions with fluorinated versus non-fluorinated molecules. These effects are inherent to the specific properties of fluorine such as the size, the electronegativity, the chelation with metal cations, the hydrogen-bonding ability, the electrostatic and stereoelectronic interactions with neighbouring groups. The use of the effects of fluorine for a desirable goal in asymmetric synthesis is exemplified hereafter.