title: Gem-difluorination of aminoalkynes via highly reactive dicationic species in superacid HF-SbF5: application to the efficient synthesis of difluorinated cinchona alkaloid derivatives.
abstract: A variety of alkynylated amines, amides, and imides are reacted in the superacid system HF-SbF5 to give regioselectively new beta-gem-difluoroamines. The reaction, which is not observed in pure HF, is consistent with the formation of a dicationic intermediate (i.e., both vinylic and adjacent protonated N-ammonium cations). Application to the regioselective and efficient synthesis of difluorinated cinchona alkaloid derivatives is described.
authors.affiliation: Laboratoire Synthèse et Réactivité des Substances Naturelles, University of Poitiers, CNRS, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France.
authors.forename: Anne-Céline
authors.initials: AC
authors.lastname: Cantet
authors.forename: Hélène
authors.initials: H
authors.lastname: Carreyre
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gesson
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Jouannetaud
authors.forename: Brigitte
authors.initials: B
authors.lastname: Renoux
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D000965:Antimony / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002930:Cinchona Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry*; D054879:Halogenation; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry*; D007094:Imides / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D000577:Amides; D000588:Amines; D002412:Cations; D002930:Cinchona Alkaloids; D006845:Hydrocarbons, Fluorinated; D007094:Imides; C529140:antimony pentafluoride; D000965:Antimony; D005459:Fluorides; D006858:Hydrofluoric Acid