title: α-Halogenoacetanilides as hydrogen-bonding organocatalysts that activate carbonyl bonds: fluorine versus chlorine and bromine.
abstract: α-Halogenoacetanilides (X=F, Cl, Br) were examined as H-bonding organocatalysts designed for the double activation of CO bonds through NH and CH donor groups. Depending on the halide substituents, the double H-bond involved a nonconventional CH⋅⋅⋅O interaction with either a HCXn (n=1-2, X=Cl, Br) or a HCAr bond (X=F), as shown in the solid-state crystal structures and by molecular modeling. In addition, the catalytic properties of α-halogenoacetanilides were evaluated in the ring-opening polymerization of lactide, in the presence of a tertiary amine as cocatalyst. The α-dichloro- and α-dibromoacetanilides containing electron-deficient aromatic groups afforded the most attractive double H-bonding properties towards CO bonds, with a NH⋅⋅⋅O⋅⋅⋅HCX2 interaction.
authors: Institut des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, 351 cours de la Libération, 33405 Talence (France), Fax: (+33) 54000-6158.
authors: Sylvain
authors: S
authors: Koeller
authors: Coralie
authors: C
authors: Thomas
authors: Fréderic
authors: F
authors: Peruch
authors: Alain
authors: A
authors: Deffieux
authors: Stéphane
authors: S
authors: Massip
authors: Jean-Michel
authors: JM
authors: Léger
authors: Jean-Pierre
authors: JP
authors: Desvergne
authors: Anne
authors: A
authors: Milet
authors: Brigitte
authors: B
authors: Bibal
mesh_terms: D000083:Acetanilides / Q000737:chemistry*; D001966:Bromine / Q000737:chemistry*; D002384:Catalysis; D002713:Chlorine / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D005461:Fluorine / Q000737:chemistry*; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory
chemical_list: D000083:Acetanilides; D006846:Hydrocarbons, Halogenated; D005461:Fluorine; D002713:Chlorine; D005459:Fluorides; D001966:Bromine
keywords: hydrogen bonds; lactide; noncovalent interactions; organocatalysis; ring-opening polymerization