Study of a new rate increasing "base effect" in the palladium-catalyzed amination of aryl iodides.
Evidence for an interphase deprotonation of Pd(II)-amine complexes with weak carbonate base has been gained for the first time. When a rate-limiting deprotonation step is involved in the catalytic cycle, controlling the structure (shape and size of the particles) and/or molar excess of the carbonate base used can significantly increase the reaction rate of Buchwald-Hartwig aminations. By taking such a "base effect" into account a general protocol for the intermolecular amination of aryl iodides with all types of amines has been developed based on a standard Pd-BINAP catalyst, using cesium carbonate as the base.
Meyers
Caroline
C
Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Maes
Bert U W
BU
Loones
Kristof T J
KT
Bal
Gunther
G
Lemière
Guy L F
GL
Dommisse
Roger A
RA