title: Skeleton decoration of NHCs by amino groups and its sequential booster effect on the palladium-catalyzed Buchwald-Hartwig amination.
abstract: A challenging synthetic modification of PEPPSI-type palladium pre-catalysts consisting of a stepwise incorporation of one and two amino groups onto the NHC skeleton was seen to exert a sequential enhancement of the electronic donor properties. This appears to be positively correlated with the catalytic performances of the corresponding complexes in the Buchwald-Hartwig amination. This is illustrated, for example, by the quantitative amination of 4-chloroanisole by morpholine within 2 h at 25 °C with a 2 mol% catalyst/substrate ratio or by a significant reduction of catalytic loading (down to 0.005 mol%) for the coupling of aryl chlorides with anilines (max TON: 19,600).
authors.affiliation: CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP44099, 31077 Toulouse Cedex 4 (France) http://www.lcc-toulouse.fr/lcc/spip.php?article24; Université de Toulouse, UPS, INPT, 31077 Toulouse (France).
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Vincent
authors.initials: V
authors.lastname: César
authors.forename: Golo
authors.initials: G
authors.lastname: Storch
authors.forename: Noël
authors.initials: N
authors.lastname: Lugan
authors.forename: Guy
authors.initials: G
authors.lastname: Lavigne
keywords: N-heterocyclic carbenes; amination reactions; amines; homogeneous catalysis; palladium