title: Synthesis of 4-fluoromethylsydnones and their participation in alkyne cycloaddition reactions.
abstract: We report the synthesis and some structural studies of 4-trifluoromethyl, 4-difluoromethyl-, and 4-monofluoromethylsydnones. All but the latter compounds are stable and represent effective precursors to a range of pyrazoles after cycloaddition reactions with alkynes. The cycloadditions are generally highly regioselective and provide 5-fluoromethylpyrazole products, although we have observed that Bn-substituted sydnones can provide an unexpected alkyne insertion mode that generates the 3-fluoromethyl isomer.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Foster
authors.forename: Harry
authors.initials: H
authors.lastname: Adams
authors.forename: Harald
authors.initials: H
authors.lastname: Jakobi
authors.forename: Joseph P A
authors.initials: JP
authors.lastname: Harrity
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D015394:Molecular Structure; D013558:Sydnones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D013558:Sydnones