Efficient construction of C–C bonds from aryl halides/aryl esters with arylboronic acids catalysed by palladium(II) thiourea complexes
作者:Manikandan Thimma Sambamoorthy、Ramesh Rengan、Malecki Jan Grzegorz
DOI:10.1002/aoc.5181
日期:2019.11
Interestingly, the palladium(II) thiourea complexes showed the highest catalytic activity with 0.1 mol% catalyst loading in Suzuki–Miyaura cross‐coupling reactions utilizing a range of aryl bromides/unactivated aryl chlorides with arylboronicacids as coupling partners in aqueous–organic media. Syntheses of diaryl ketones using aryl esters and arylboronicacids as coupling partners were also achieved with low
Selective palladium-catalysed arylation of 2,6-dibromopyridine using N-heterocyclic carbene ligands
作者:D. Prajapati、C. Schulzke、M. K. Kindermann、A. R. Kapdi
DOI:10.1039/c5ra10561g
日期:——
A selective palladium-catalysed arylation of 2,6-dibromopyridine has been developed by employing N-heterocyclic carbene ligands. Selective mono-arylation was performed in water/acetonitrile solvent system at ambient temperature with catalyst loading of 0.1 mol%. This reaction was also found to proceed smoothly in water although at a slightly elevated temperature of 80 °C. 2,6-Disubstituted and diversely
Highly efficient palladium(<scp>ii</scp>) hydrazone based catalysts for the Suzuki coupling reaction in aqueous medium
作者:Subramanian Muthumari、Rengan Ramesh
DOI:10.1039/c6ra06734d
日期:——
and reveal the presence of a distorted square planar geometry around the Pd ion. The complexes 1–5 (0.05 mol%) have been found to be a highly active catalytic system in the mono and double Suzuki–Miyaura cross coupling reaction of deactivated aryl and heteroaryl bromides with different types of aryl boronic acids in neat water and the maximum yield was up to >99%. Notably, these catalysts work well with
Pd-Catalyzed Decarboxylation and Dual C(sp<sup>3</sup>)–H Functionalization Protocols for the Synthesis of 2,4-Diarylpyridines
作者:Raghuram Gujjarappa、Nagaraju Vodnala、Mohan Kumar、Chandi C. Malakar
DOI:10.1021/acs.joc.8b02971
日期:2019.5.3
The Pd-catalyzed decarboxylation and dualC(sp3)–Hbondfunctionalization approaches have been described for the preparation of symmetrical and unsymmetrical 2,4-diarylpyridines. The developed transformations were realized using nonactivated aromatic ketones and amino acids as C–N sources. The efficacy of the catalyst and reagent combination drives the transformation toward the formation of desired
Hf(OTf)4-catalyzed unprecedented annulation of an enamine with triethyl orthoformate leading to the preparation of tetrasubstituted symmetricalpyridine derivatives without an oxidant is described. This method accommodated the single-step synthesis of a disubstitutedsymmetricalpyridine using an acetophenone derivative, triethyl orthoformate, and ammonium acetate (NH4OAc).