Asymmetric Synthesis of QUINAP via Dynamic Kinetic Resolution

A palladium-catalyzed, atroposelective C-P coupling process has been developed for the asymmetric synthesis of QUINAP and its derivatives in high enantiomeric excess. Bromide, triflate (OTf) and 4-methanesulfonylbenzenesulfonate (OSs) precursors were studied, leading in the case of the triflate to a novel dynamic kinetic resolution involving isomerization of an arylpalladium intermediate. The operationally simple methods described in this communication afford these important ligands in good to high yields and selectivity using low catalyst loading (<= 3 mol % Pd).