title: Synthesis of geminal difluorides by oxidative desulfurization-difluorination of alkyl aryl thioethers with halonium electrophiles in the presence of fluorinating reagents and its application for 18F-radiolabeling.
abstract: Various ω-substituted 1,1-difluoroalkanes are synthesized in good yields from alkyl aryl thioethers by a new oxidative desulfurization-difluorination protocol with the reagents combination of 1,3-dibromo-5,5-dimethylhydantoin (DBH) as an oxidizer and pyridine·9HF (Py·9HF) as a fluoride source. The reaction proceeds via a fluoro-Pummerer-type rearrangement followed by an oxidative desulfurization-fluorination step. Starting from α-fluorinated thioethers, this reaction is promising for (18)F-labeling (τ(1/2) = 110 min) of ligands applicable for positron emission tomography (PET). Using the combination of DBH and carrier-added Py·9H[(18)F]F, an (18)F-labeled difluoride was synthesized from the corresponding α-fluoro thioether with a radiochemical yield of 9%.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Hugenberg
authors.forename: Stefan
authors.initials: S
authors.lastname: Wagner
authors.forename: Klaus
authors.initials: K
authors.lastname: Kopka
authors.forename: Otmar
authors.initials: O
authors.lastname: Schober
authors.forename: Michael
authors.initials: M
authors.lastname: Schäfers
authors.forename: Günter
authors.initials: G
authors.lastname: Haufe
mesh_terms: D005462:Fluorine Radioisotopes / Q000737:chemistry*; D054879:Halogenation; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism; D013440:Sulfides / Q000737:chemistry*
chemical_list: D005462:Fluorine Radioisotopes; D006845:Hydrocarbons, Fluorinated; D011725:Pyridines; D013440:Sulfides; C023666:pyridine; D006858:Hydrofluoric Acid