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Bond Addition (bond + addition)
Selected AbstractsCandida antarctica Lipase B (CAL-B)-Catalyzed Carbon-Sulfur Bond Addition and Controllable Selectivity in Organic MediaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2008Feng-Wen Lou Abstract A novel enzymatic, promiscuous protocol for Candida antarctica lipase B (CAL-B)-catalyzed carbon-sulfur bond addition is described. Some control experiments have been designed to demonstrate the catalytic specificity of CAL-B. Selectivity between anti-Markovnikov addition and Markovnikov addition was achieved in different organic media. A series of thioether-containing ester functional groups was synthesized under the catalysis of CAL-B at 50,°C. All the products were characterized by spectroscopic methods (IR, NMR, ESI-MS). [source] New Catalytic System for S,S and Se,Se Bond Addition to Alkynes Based on Phosphite Ligands.CHEMINFORM, Issue 29 2005Valentine P. Ananikov Abstract For Abstract see ChemInform Abstract in Full Text. [source] Candida antarctica Lipase B (CAL-B)-Catalyzed Carbon-Sulfur Bond Addition and Controllable Selectivity in Organic MediaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2008Feng-Wen Lou Abstract A novel enzymatic, promiscuous protocol for Candida antarctica lipase B (CAL-B)-catalyzed carbon-sulfur bond addition is described. Some control experiments have been designed to demonstrate the catalytic specificity of CAL-B. Selectivity between anti-Markovnikov addition and Markovnikov addition was achieved in different organic media. A series of thioether-containing ester functional groups was synthesized under the catalysis of CAL-B at 50,°C. All the products were characterized by spectroscopic methods (IR, NMR, ESI-MS). [source] Two Distinct Mechanisms of Alkyne Insertion into the Metal,Sulfur Bond: Combined Experimental and Theoretical Study and Application in CatalysisCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2010Valentine Abstract The present study reports the evidence for the multiple carbon,carbon bond insertion into the metal,heteroatom bond via a five-coordinate metal complex. Detailed analysis of the model catalytic reaction of the carbon,sulfur (CS) bond formation unveiled the mechanism of metal-mediated alkyne insertion: a new pathway of CS bond formation without preliminary ligand dissociation was revealed based on experimental and theoretical investigations. According to this pathway alkyne insertion into the metal,sulfur bond led to the formation of intermediate metal complex capable of direct CS reductive elimination. In contrast, an intermediate metal complex formed through alkyne insertion through the traditional pathway involving preliminary ligand dissociation suffered from "improper" geometry configuration, which may block the whole catalytic cycle. A new catalytic system was developed to solve the problem of stereoselective SS bond addition to internal alkynes and a cost-efficient Ni-catalyzed synthetic procedure is reported to furnish formation of target vinyl sulfides with high yields (up to 99,%) and excellent Z/E selectivity (>99:1). [source] | ||||||||||