title: Oxidative aliphatic C-H fluorination with fluoride ion catalyzed by a manganese porphyrin.
abstract: Despite the growing importance of fluorinated organic compounds in drug development, there are no direct protocols for the fluorination of aliphatic C-H bonds using conveniently handled fluoride salts. We have discovered that a manganese porphyrin complex catalyzes alkyl fluorination by fluoride ion under mild conditions in conjunction with stoichiometric oxidation by iodosylbenzene. Simple alkanes, terpenoids, and even steroids were selectively fluorinated at otherwise inaccessible sites in 50 to 60% yield. Decalin was fluorinated predominantly at the C2 and C3 methylene positions. Bornyl acetate was converted to exo-5-fluoro-bornyl acetate, and 5α-androstan-17-one was fluorinated selectively in the A ring. Mechanistic analysis suggests that the regioselectivity for C-H bond cleavage is directed by an oxomanganese(V) catalytic intermediate followed by F delivery via an unusual manganese(IV) fluoride that has been isolated and structurally characterized.
authors.affiliation: Department of Chemistry, Frick Chemistry Laboratory, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Xiongyi
authors.initials: X
authors.lastname: Huang
authors.forename: Mu-Jeng
authors.initials: MJ
authors.lastname: Cheng
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Nielsen
authors.forename: William A
authors.initials: WA
authors.lastname: Goddard
authors.forename: John T
authors.initials: JT
authors.lastname: Groves
mesh_terms: D001892:Camphanes / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D015195:Drug Design; D005459:Fluorides / Q000737:chemistry*; D054879:Halogenation; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D007462:Iodobenzenes / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008345:Manganese / Q000737:chemistry*; D008697:Methane / Q000737:chemistry; D009281:Naphthalenes / Q000737:chemistry; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D001892:Camphanes; D007462:Iodobenzenes; D007477:Ions; D009281:Naphthalenes; D011166:Porphyrins; C071528:bornyl acetate; D008345:Manganese; D002244:Carbon; D006859:Hydrogen; C007229:decalin; C031905:iodobenzene; D008697:Methane; D005459:Fluorides