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α‐Halogenoacetanilides as Hydrogen‐Bonding Organocatalysts that Activate Carbonyl Bonds: Fluorine versus Chlorine and Bromine
Author(s) -
Koeller Sylvain,
Thomas Coralie,
Peruch Fréderic,
Deffieux Alain,
Massip Stéphane,
Léger JeanMichel,
Desvergne JeanPierre,
Milet Anne,
Bibal Brigitte
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201303662
Subject(s) - chemistry , hydrogen bond , bromine , catalysis , double bond , chlorine , halide , polymer chemistry , amine gas treating , crystal structure , medicinal chemistry , fluorine , halogen bond , ring (chemistry) , crystallography , organic chemistry , molecule
α‐Halogenoacetanilides (X=F, Cl, Br) were examined as H‐bonding organocatalysts designed for the double activation of CO bonds through NH and CH donor groups. Depending on the halide substituents, the double H‐bond involved a nonconventional CH⋅⋅⋅O interaction with either a HCX n ( n =1–2, X=Cl, Br) or a HC Ar 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 CO bonds, with a NH⋅⋅⋅O⋅⋅⋅HCX 2 interaction.