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Efficient Enantioselective Synthesis (efficient + enantioselective_synthesis)
Selected AbstractsEfficient Enantioselective Syntheses of Sertraline, 2-Epicatalponol and Catalponol from Tetralin-1,4-dioneADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Alvaro Enriquez Garcia Abstract Tetralin-1,4-dione, the stable tautomer of dihydroxynaphthalene, was reduced with catecholborane in the presence of 3,3-diphenyl-1-butyltetrahydro-3H -pyrrolo[1,2- c][1,3,2]oxazaborole as catalyst to give enantiomerically highly enriched 4-hydroxy-1-tetralone (99% ee) in an efficient one-pot procedure. The R -enantiomer provided a rapid access to sertraline while the S -enantiomer was converted into 2-epicatalponol and catalponol. A more selective enantioselective route to the antithermitic catalponol made use of the planar chiral tricarbonylchromium complex of hydroxytetralone. Its precursor chromium(tricarbonyl)[,6 -(1-4,4a,8a)-tetralin-5,8-dione] was obtained via direct complexation of 1,4-dihydroxynaphthalene using chromium(tricarbonyl)- tris(ammonia) and boron trifluoride etherate as source of the chromium(tricarbonyl) fragment. Enolate prenylation was best carried out in the presence of a tetraamine ligand. Complete inversion of the stereogenic center bearing the prenyl group of the initially obtained tetralone complex was achieved via enolate formation followed by protonation. [source] The Development of a Convergent and Efficient Enantioselective Synthesis of the Bengamides via a Common Polyol IntermediateHELVETICA CHIMICA ACTA, Issue 12 2002Robert An efficient, general synthetic route to the bengamide family of antitumor agents from a common polyol thioester is described. Consecutive aldol condensations afford the protected polyol thioester side chain suitable for coupling to the bengamides. A novel chiral-phase-transfer-catalyzed enantioselective alkylation affords the properly functionalized caprolactams required for the synthesis of more-complex members of the bengamide family. Use of the methyl 2-naphthyl ether protecting group, compatible with the boron Lewis acids required for enantioselective aldol condensation, allows direct access to all the bengamides. [source] ChemInform Abstract: Rh-Catalyzed Asymmetric Hydrogenation of ,-Phthalimido-Substituted ,,,-Unsaturated Carboxylic Acid Esters: An Efficient Enantioselective Synthesis of ,-Aryl-,-amino Acids.CHEMINFORM, Issue 14 2008Jun Deng 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Efficient Enantioselective Synthesis of Cyclopropanes from SulfonylpyrazolinesCHEMINFORM, Issue 35 2005Jose L. Garcia Ruano Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Efficient Enantioselective Synthesis of (R)-(-)-Carnitine from Glycerol.CHEMINFORM, Issue 7 2001Mauro Marzi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Efficient Total Synthesis of (,)-(3S,6R)-3,6-Dihydroxy-10-methylundecanoic AcidEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2007Satyendra Kumar Pandey Abstract An efficient enantioselective synthesis of (,)-(3S,6R)-3,6-dihydroxy-10-methylundecanoic acid (1) from epichlorohydrin is described. The key steps include Jacobsen's HKR, Sharpless asymmetric dihydroxylation, regioselective opening of epoxide and cyclic sulfate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Enantioselective Synthesis of Chiral ,-Aryloxy Alcohols by Ruthenium-Catalyzed Ketone Hydrogenation via Dynamic Kinetic Resolution (DKR)ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Wen-Ju Bai Abstract A highly efficient enantioselective synthesis of chiral ,-aryloxy alcohols by the {RuCl2[(S)-SDP][(R,R)-DPEN]} [(Sa,R,R)- 1a; SDP=7,7,-bis(diarylphosphino)-1,1,-spirobiindane; DPEN=trans -1,2-diphenylethylenediamine] complex-catalyzed asymmetric hydrogenation of racemic ,-aryloxydialkyl ketones via dynamic kinetic resolution (DKR) has been developed. Enantioselectivities of up to 99% ee with good to high cis/anti -selectivities (up to>99:1) were achieved. [source] | ||||||||||