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Straightforward Methodology (straightforward + methodology)
Selected AbstractsStraightforward Methodology for the Enantioselective Synthesis of Benzo[a]- and Indolo[2,3-a]quinolizidines.CHEMINFORM, Issue 50 2007Mercedes Amat 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] A Straightforward Methodology for the Introduction of Aryl and Vinyl Substituents in the 5 or 7 Position of 8-Hydroxyquinoline.CHEMINFORM, Issue 35 2006Francesco Babudri 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] Dynamic Kinetic Resolution and Desymmetrization Processes: A Straightforward Methodology for the Enantioselective Synthesis of PiperidinesCHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2006Mercedes Amat Prof. Abstract A straightforward procedure for the synthesis of enantiopure polysubstituted piperidines is reported. It involves the direct generation of chiral non-racemic oxazolo[3,2- a]piperidone lactams that already incorporate carbon substituents on the heterocyclic ring and the subsequent removal of the chiral auxiliary. The key step is a cyclocondensation reaction of (R)-phenylglycinol or other amino alcohols with racemic or prochiral ,-oxo (di)acid derivatives in highly stereoselective processes involving dynamic kinetic resolution and/or desymmetrization of diastereotopic or enantiotopic ester groups. Se describe un procedimiento directo para la síntesis enantioselectiva de piperidinas polisustituidas. Consiste en la generación directa de oxazolo[3,2-a]piperidonas quirales no racémicas que ya incorporan sustituyentes carbonados en las diferentes posiciones del heterociclo, y en la posterior eliminación del auxiliar quiral. La etapa clave es una reacción de ciclocondensación entre el (R)-fenilglicinol, u otros amino alcoholes quirales, con derivados de , -oxo ácidos racémicos o proquirales, en procesos altamente estereoselectivos que implican una resolución cinética dinámica y/o la desimetrización de grupos diastereotópicos o enantiotópicos. [source] The First Catalytic Enantioselective Aldol-Type Reaction of Ethyl Diazoacetate to KetonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Fides Benfatti Abstract The aldol-type addition to ketones still represents a great challenge in asymmetric catalysis. Recently, the direct aldol reaction between the commercially available ethyl diazoacetate and aldehydes has attracted increasing attention. Ethyl diazoacetate is economical and allows further transformation of the aldol adduct obtained. We present a solution for the arduous, and not previously described, addition of diazoacetate to ketones. Our procedure employs commercially available norephedrine-derived ligands and dialkylzinc reagents [R2Zn: (diethylzinc, Et2Zn; dimethylzinc, Me2Zn)] as starting materials, therefore the active catalyst is prepared with a very straightforward methodology. Remarkably, the reaction gives good enantiomeric excesses with ,-halo ketones, a class of compounds that has not been commonly used in enolate addition. [source] | ||||||||||