Heterogeneous Pd-catalyzed heterocycles

Heterogeneous Pd-Catalyzed Heterocycle Synthesis via C-H Activation 451 Table 14.1 Scope of PdfOHjj-C-catalyzed intramolecular direct arylation reactions. ... 

An immobilized version of a Heck reaction catalyzed by Pd nanoparticles has been very recently described by Kaiimi and Enders [289]. The nanoparticles were obtained as a result of the covalent anchoring of a N-heterocyclic carbene palladium/ionic liquid matrix on a silica surfece and their nature was confirmed by TEM coupled with EDX analysis. The catalyst showed high thermal stability (up to 280 °C) and could be recycled four times for the reaction of bromobenzene with methylacrylate achieving a total turnover number of 36600. After carrying out a hot filtration process, the authors could not detect any Pd in the filtrate. The filtrate also showed no further reaction progress. Erom these findings the authors concluded that the reaction was, in their case, indeed catalyzed by the heterogeneous Pd particles and not from monomolecular Pd-complexes leached from the sur ce. 

Carbon-carbon coupling reactions of heterocycles catalyzed by heterogeneous Pd catalysts 07CRV133. 

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