title: Enantioselective gem-chlorofluorination of active methylene compounds using a chiral spiro oxazoline ligand.
abstract: Highly enantioselective gem-chlorofluorination of active methylene compounds was carried out by using a copper(II) complex of a chiral spiro pyridyl monooxazoline ligand. This reaction yielded α-chloro-α-fluoro-β-keto esters and α-chloro-α-fluoro-β-keto phosphonates with up to 92% ee. The resulting dihalo β-keto ester was converted into various α-fluoro-α-heteroatom-substituted carbonyl compounds via nucleophilic substitution without loss of optical purity. A fully protected β-amino acid with a gem-chlorofluoromethylene function was also synthesized.
authors.affiliation: Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Japan. shiba@ens.tut.ac.jp
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Shibatomi
authors.forename: Akira
authors.initials: A
authors.lastname: Narayama
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Soga
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Muto
authors.forename: Seiji
authors.initials: S
authors.lastname: Iwasa
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: C523706:(Cu(4-methylcoumarin-6,7-dioxactetate)(phenanthroline)2); D000596:Amino Acids; D006846:Hydrocarbons, Halogenated; D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper