4-Aryl-2-quinolones through a Pseudo-Domino Heck/Buchwald–Hartwig Reaction in a Molten Tetrabutylammonium Acetate/ Tetrabutylammonium Bromide Mixture
作者:Gianfranco Battistuzzi、Roberta Bernini、Sandro Cacchi、Ilse De Salve、Giancarlo Fabrizi
DOI:10.1002/adsc.200600342
日期:2007.2.5
prepared from readily available o-bromocinnamamide and aryl iodides using phosphine-free palladium(II) acetate as the precatalyst and a molten tetra(n-butyl)ammonium acetate/tetra(n-butyl)ammonium bromidemixture as the reaction medium. The reaction proceeds through a pseudo-domino process involving two mechanistically independent, sequential catalytic cycles: a Heck reaction followed by an intramolecular
highly efficient palladium-catalyzedsynthesis of unsymmetrically substituted 3-(diarylmethylenyl)indolinones from readily accessible starting materials is developed. The domino reaction involves a sequence of intermolecular carbopalladation, C-H activation, and C-C bond formation. A plausible mechanistic pathway for the reaction is discussed on the basis of the kinetic isotope effect [K(H)/K(D) (intermolecular)