Home About us Contact
|
Home About us Contact | ||
|
|
||
Biaryl Synthesis (biaryl + synthesis)
Selected AbstractsRemarkably Effective Phosphanes Simply with a PPh2 Moiety: Application to Pd-Catalysed Cross-Coupling Reactions for Tetra- ortho -substituted Biaryl SynthesesCHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2010Ming So Expanding the horizons of ArPPh2: New applications of triarylphosphane ligands are presented. The Pd,L1 and Pd,L2 complexes offer exceptionally high activity in Suzuki,Miyaura cross-couplings of aryl chlorides. The extremely congested synthesis of tetra- ortho -substituted biaryl compounds is achieved for the first time by simply using triarylphosphane ligands. [source] Light-Fluorous Safety-Catch Arylgermanes , Exceptionally Robust, Photochemically Activated Precursors for Biaryl Synthesis by Pd(0)-Catalyzed Cross-Coupling.CHEMINFORM, Issue 46 2007Alan C. Spivey Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Stille Reactions with Tetraalkylstannanes and Phenyltrialkylstannanes in Low Melting Sugar-Urea-Salt MixturesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 15 2006Giovanni Imperato Abstract The transfer of simple alkyl groups in Stille reactions usually requires special solvents (HMPA) or certain organotin reagents (stannatranes, monoorganotin halides) to be efficient. Using low-melting mixtures of sugar, urea and inorganic salt as solvent, a fast and efficient palladium-catalyzed alkyl transfer with tetraalkyltin reagents was observed. The high polarity and nucleophilic character of the solvent melt promotes the reaction. Stille biaryl synthesis using electron-poor and electron-rich aryl bromides proceeds with quantitative yields in the sugar-urea-salt melt. Catalyst loading may be reduced to 0.001 mol,% and the catalyst melt mixture remains active in several reaction cycles. Showing the same or improved performance for Stille reactions than organic solvents and allowing a very simple work up, sugar-urea-salt melts are a non-toxic and cheap alternative reaction medium available in bulk quantities for the catalytic process. [source] The development of a ,safety-catch' arylgermane for biaryl synthesis by palladium-catalysed germyl-stille cross-couplingAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 7 2007Alan C. Spivey Abstract The Pd(0) catalysed cross-coupling of arylgermanes with aryl bromides is shown to require at least two labile heteroatom ligands on the Ge centre to allow efficient nucleophilic activation by fluoride. Dichloroarylgermanes 7a and 7b are shown to cross-couple to a series of aryl bromides with moderate efficiency using activation by KF in DMF. Bis(2-naphthylmethyl)arylgermane 18b is identified as a ,safety-catch' precursor to this type of cross-coupling substrate. The 2-naphthylmethyl substituents can be removed via photolytic oxidation in the presence of Cu(BF4)2 and the resulting species, although not characterized, participates in cross-coupling using activation by TBAF in DMF. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||