- Low-Temperature Ag/Pd-catalyzed decarboxylative cross-coupling of aryl trflates with aromatic carboxylate salts
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Chemical Equation Presented At 50°C lower than the best known copper catalysts, a catalytic silver(I)/ palladium(II) system allows the decarboxylative cross-coupling of arenecarboxylates with aryl triflates at temper-atures as low as 120°C. Remarkably, polychlorinated and many heterocyclic arenecarboxylates are converted for the first time in high yields. FG = functional group.
- Goossen, Lukas J.,Lange, Paul P.,Rodriguez, Nuria,Linder, Christophe
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supporting information; experimental part
p. 3906 - 3909
(2010/07/03)
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- Cross-coupling reactions of aromatic and heteroaromatic silanolates with aromatic and heteroaromatic halides
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The alkali-metal salts (potassium and sodium) of a large number of aryl- and heteroarylsilanols undergo efficient cross-coupling with a wide range of aromatic bromides and chlorides under mild conditions to form polysubstituted biaryls. The critical feature for the success of these coupling reactions and their considerable scope is the use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and sterically hindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate and (2,6-dichlorophenyl)dimethylsilanolate prepared as their sodium salts showed excellent activity in the coupling reactions, in the former case also with aromatic chlorides. General methods for the efficient synthesis of a wide range of aromatic silanols are also described.
- Denmark, Scott E.,Smith, Russell C.,Chang, Wen-Tau T.,Muhuhi, Joseck M.
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supporting information; experimental part
p. 3104 - 3118
(2009/08/07)
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- Physical, spectral and chromatographic properties of all 209 individual PCB congeners
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Through the use of two capillary GC columns: 40% octadecyl/ 15% phenyl methyl siloxane and 50% phenyl methyl siloxane, it was possible to separate 201 PCB congeners with only four unresolved pairs. The data compiled in this study for all 209 congeners will aid in the identification of selected individual components of these environmental pollutants. The use of this data also presents the opportunity for the improved quantification of the commercial PCB formulations. -from Authors
- Bolgar,et al.
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p. 2687 - 2705
(2007/10/03)
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