HandaPhos: A General Ligand Enabling Sustainable ppm Levels of Palladium-Catalyzed Cross-Couplings in Water at Room Temperature
作者:Sachin Handa、Martin P. Andersson、Fabrice Gallou、John Reilly、Bruce H. Lipshutz
DOI:10.1002/anie.201510570
日期:2016.4.11
complexed in a 1:1 ratio with Pd(OAc)2, enables Pd‐catalyzed cross‐couplings to be run using ≤1000 ppm of this pre‐catalyst. Applications to Suzuki–Miyaura reactions involving highly funtionalized reaction partners are demonstrated, all run using environmentally benign nanoreactors in water at ambient temperatures. Comparisons with existing state‐of‐the‐art ligands and catalysts are discussed herein.
Three newpalladium catalysts, prepared via reactions of PdCl2 with readily obtained and inexpensive dicationic imidazolium salts, have been developed for the Suzuki reaction. The pre-catalyst was formed in situ using the imidazolium ligand, base and Pd metal precursor in 1,4-dioxane. This palladium catalyst provides a convenient and general method for the synthesis of biaryls from aryl bromides, activated
The palladium complexes of a series of simple Schiff base ligands with or without phenolic hydroxyl groups have been found to be the excellent catalysts for the Suzuki–Miyaura reactions of aryl iodides, aryl bromides and activated aryl chlorides under ambient conditions in aqueous ethanol media. The introduction of phenolic hydroxyl and/or pyridine groups to the ligands increased the catalytic activity. Under optimal reaction conditions, satisfactory to excellent yields of biaryls were obtained with a wide range of substrates for relatively low loadings of catalyst. Phenolic hydroxyl group and N4-type Schiff base ligands (L1-2) have been proven to be the excellent catalysts for the Suzuki–Miyaura reactions of aryl iodides, aryl bromides and activated aryl chlorides in aqueous ethanol under ambient. Furthermore, a diverse choice of functionalized arylboronic acids bearing difluoro, trifluoro and trifluoromethyl substituents were successfully coupled (>97 %) .
cyclopentane/[PdCl(C3H5)]2 system catalyses efficiently the cross-coupling of aryl bromides with functionalised arylboronicacids. The electronic properties of the arylboronicacids seem to have a minor influence on the reaction rate. Better results were generally obtained for the reaction of electron poor aryl bromides associated with electron rich arylboronicacids rather than the contrary.
Copper + Nickel-in-Charcoal (Cu−Ni/C): A Bimetallic, Heterogeneous Catalyst for Cross-Couplings
作者:Bruce H. Lipshutz、Danielle M. Nihan、Ekaterina Vinogradova、Benjamin R. Taft、Žarko V. Bošković
DOI:10.1021/ol801676u
日期:2008.10.2
catalyst composed of copper and nickel oxide particles supported within charcoal has been developed. It catalyzes cross-couplings that traditionally use palladium, nickel, or copper, including Suzuki-Miyaura reactions, Buchwald-Hartwig aminations, vinylalane alkylations, etherifications of arylhalides, arylhalide reductions, asymmetric conjugate reductions of activated olefins, and azide-alkyne "click"