Asymmetric fluorination of β-keto esters catalyzed by chiral rare earth perfluorinated organophosphates

Abstract

Novel chiral rare earth metal complexes bearing perfluorinated binaphthyl phosphate ligand RE[( R)-F 8BNP] 3 (RE = rare earth; F 8BNP = 5,5′,6,6′,7,7′,8,8′-octafluoro-1,1′-binaphthyl-2,2′-diyl phosphate) have been synthesized and used as a catalyst for the asymmetric electrophilic fluorination reaction of β-keto esters. The use of Sc[( R)-F 8BNP] 3 catalyst in combination with 1-fluoropyridinium triflate (NFPY–OTf) as a fluorinating agent was found to give the desired α-fluoro-β-keto esters in high chemical yields and enantiomeric excesses (up to 88% ee) under mild conditions.