title: Regioselectivity in intermolecular Pauson-Khand reactions of dissymmetric fluorinated alkynes.
abstract: Stoichiometric and catalytic intermolecular Pauson-Khand reactions (PKRs) of dissymmetric fluorinated alkynes were performed, affording regioselectively α-fluorinated cyclopentenones. Ethyl 4,4,4-trifluorobutynoate was an excellent substrate; its reaction with norbornadiene gave the corresponding PKR adduct in good yield and complete regioselectivity. Conjugate addition of nitroalkanes or cyanide to this adduct is stereospecific and entails concomitant loss of a trifluoromethyl group. This reaction can be exploited to prepare cyclopentenones featuring quaternary centers.
authors.affiliation: Unitat de Recerca en Síntesi Asimètrica (URSA-PCB), Institute for Research in Biomedicine (IRB) and Departament de Química Orgànica, Universitat de Barcelona, c/Baldiri Reixac, 10, E-0 8028 Barcelona, Spain. jean-claude.kizirian@univ-tours.fr
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Kizirian
authors.forename: Nuria
authors.initials: N
authors.lastname: Aiguabella
authors.forename: Albert
authors.initials: A
authors.lastname: Pesquer
authors.forename: Santos
authors.initials: S
authors.lastname: Fustero
authors.forename: Paula
authors.initials: P
authors.lastname: Bello
authors.forename: Xavier
authors.initials: X
authors.lastname: Verdaguer
authors.forename: Antoni
authors.initials: A
authors.lastname: Riera
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D054879:Halogenation; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000480:Alkynes