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Chiral Sulfoxide (chiral + sulfoxide)
Selected AbstractsElectroenzymatic Synthesis of Chiral SulfoxidesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2006C. Kohlmann Abstract Chloroperoxidase (CPO) from Caldariomyces fumago (E.C.,1.11.1.10) is able to enantioselectively oxidize various sulfides to the corresponding (R)-enantiomer of the sulfoxides. For these oxidations the enzyme requires an oxidant. Most commonly, tert -butyl hydroperoxide (TBHP) and hydrogen peroxide are used. As it is known that these oxidants inactivate the enzyme, the enzymatic reaction was combined with the electrochemical in situ generation of hydrogen peroxide. As substrates for this combination of an enzymatic and an electrochemical reaction methyl p-tolyl sulfide, 1-methoxy-4-(methylthio)benzene and N-MOC- L -methionine methyl ester were used to carry out batch experiments. [source] ChemInform Abstract: Gold Catalysis and Chiral Sulfoxides: Enantioselective Synthesis of Dihydroisoindol-4-ols.CHEMINFORM, Issue 7 2009A. Stephen K. Hashmi 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] Asymmetric Claisen Rearrangements on Chiral Vinyl SulfoxidesCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2009Pradilla Prof., Roberto Fernández Abstract Highly diastereoselective Claisen rearrangements of acyclic allyl vinyl ethers bearing a chiral sulfoxide at C-5 provide ,- , -unsaturated aldehydes or ketones with up to two consecutive asymmetric centers in the molecule whilst preserving a useful vinyl sulfoxide. The reactivity of related vinyl sulfides and sulfones has also been examined in this work. [source] Structure determination of chiral sulfoxide in diastereomeric bicalutamide derivativesCHIRALITY, Issue 6 2009Wei Li Abstract We report on the synthesis and investigation of two diastereomers (5a and 5b) of a new bicalutamide analog with an asymmetric carbon atom and a chiral sulfoxide group. These bicalutamide analogs are novel androgen receptor antagonists with biological activities that depend significantly on the configuration of their stereogenic centers. We determined the absolute configuration at the SO center by combining X-ray and NMR measurements with quantum chemical calculations. Since 5a and 5b failed to yield satisfactory crystals for X-ray crystal structure determination, analogs 6a and 6b differing in only one remote functional group relative to the chiral sulfoxide were synthesized, which yielded satisfactory crystals. X-ray structure determination of 6a and 6b provided the absolute configuration at the chiral sulfoxide. Since the structural difference between 5 and 6 is remote from the chiral sulfoxide, the structural assignment was extended from the diastereomers of 6 to those of 5 provisionally. These assignments were verified with the help of measured and DFT-calculated proton and carbon NMR chemical shifts. Chirality, 2008. © 2009 Wiley-Liss, Inc. [source] Preparation, structure, and optical properties of chiral sulfoxides and disulfoxide with a trithiole ringHETEROATOM CHEMISTRY, Issue 1 2003Takeshi Kimura Optically active 4,9-diethyl[1,4]-dithiino[5,6- f]benzo[1,2,3]trithiole 5-oxide (3) and 4,9-diethyl[1,4]dithiino[5,6- f]benzo[1,2,3]trithiole 5,8-dioxide (4) were obtained by the asymmetric oxidation of 6,11-diethyl[1,4]dithiino[5,6- h]benzo[1,2,3,4,5]pentathiepin (1). The reaction was accompanied by desulfurization and ring-contraction reactions of the pentathiepin ring. Similarly, optically active 4,8-diethyl[1,3]dithiolo[4,5- f]benzo[1,2,3]trithiole 5-oxide (7) was produced by the analogous asymmetric oxidation of 6,10-diethyl[1,3]dithiolo[4,5- h]benzo[1,2,3,4,5]pentathiepin (2). The specific rotations of 3, 4, and 7 were measured in chloroform, and their optical purity was verified by 1H NMR with a shift reagent [Eu(hfc)3]. The structures of 4 and 7 were determined by X-ray crystallography using Cu K, radiation, and the absolute configuration of the sulfinyl group was examined based on the Flack parameter, which revealed that 4 has an RR configuration, while 7 has an S configuration. The circular dichroism spectra of 3, 4, and 7 were measured in chloroform. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:88,94, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10104 [source] | ||||||||||