Copper-Catalyzed Decarboxylative Cross-Coupling of Potassium Polyfluorobenzoates with Aryl Iodides and Bromides
作者:Rui Shang、Yao Fu、Yan Wang、Qing Xu、Hai-Zhu Yu、Lei Liu
DOI:10.1002/anie.200904916
日期:2009.11.23
For copper only: The decarboxylative cross‐coupling of readily accessible and nonvolatile potassiumpolyfluorobenzoates with aryliodides and bromides using a copper catalyst provides polyfluorobiaryls and polyfluorostilbenes in excellent yields (see scheme). Mechanistic analyses are reported for the title reaction.
The invention relates to bimesogenic compounds of formula I
wherein R
11
, R
12
, MG
11
, MG
12
, X
11
, X
12
and Sp
1
have the meaning given in claim
1
, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.
Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation of aromatic carboxylic acids
作者:Jian-Jun Dai、Jing-Hui Liu、Dong-Fen Luo、Lei Liu
DOI:10.1039/c0cc04104a
日期:——
Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation reactions of aromatic carboxylic acids are reported. The new reactions may provide alternative routes for the synthesis of some biaryls and aromatic carboxylic esters.
The reactivity of polychlorobenzenes vs. polyfluorobenzenes for palladium-catalysed direct arylation was studied. The PdCl(C3H5)(dppb)/KOAc system was found to promote the direct arylation of some polychlorobenzenes with aryl bromides. However, the reactivity of polychlorobenzenes was found to be lower than that of polyfluorobenzenes. The best yields were obtained from the coupling of 1,2,4,5-tetrachlorobenzene or 1,3,5-trichlorobenzene with electron-deficient aryl bromides. The C3 arylation of 2,5-dichlorothiophene was also found to proceed nicely.
Influence of 1,3-Difluorobenzene Substituents for Palladium-Catalyzed Direct Arylations
作者:Tao Yan、Charles Beromeo Bheeter、Henri Doucet
DOI:10.1002/ejoc.201301131
日期:2013.11
bromo, methoxy or amino) on 1,3-difluorobenzenes in their palladium-catalyseddirect C2 arylation has been explored. With most substituents, the reaction proceeds nicely using air-stable palladium catalysts (0.5–2 mol-%) and KOAc/DMA. In general, very regioselective C2-arylation was observed. Moreover, a variety of substituents on the arylbromide coupling partner (ester, acetyl, formyl, nitro, nitrile