682746-13-0Relevant articles and documents
Highly enantioselective α-aminoxylation of aldehydes and ketones with a polymer-supported organocatalyst
Font, Daniel,Bastero, Amaia,Sayalero, Sonia,Jimeno, Ciril,Pericas, Miquel A.
, p. 1943 - 1946 (2008/02/02)
The first catalytic enantioselective α-aminoxylation of aldehydes and ketones using an insoluble, polymer-supported organocatalyst (1) derived from trans-4-hydroxyproline is reported (ee: 96-99%). Reaction rates in the aminoxylation of cyclic ketones with 1 are higher than those reported with L-proline. The insoluble nature of 1 simplifies workup conditions and allows catalyst recycling without an apparent decrease in enantioselectivity or yield.
OPTICALLY ACTIVE ALPHA-AMINOOXYKETONE DERIVATIVES AND PROCESS FOR PRODUCTION THEREOF
-
Page/Page column 9; 16, (2008/06/13)
The corresponding α-aminooxy ketone is manufactured with a high yield and a high enantioselectivity. A manufacturing method for an optically active α-aminooxy ketone derivative expressed by formula (1), wherein a ketone expressed by formula (2) is caused
ORGANOCATALYSTS AND METHODS OF USE IN CHEMICAL SYNTHESIS
-
Page/Page column 37-38; 83-84, (2010/02/15)
The present invention pertains generally to compositions comprising organocatalysts that facilitate stereo-selective reactions and the method of their synthesis and use. Particularly, the invention relates to metal-free organocatalysts for facilitation of stereo--selective reactions, and the method of their synthesis and use. These compounds have the structure of the Formulas (I) and (II). Where X is independently selected from CH2, N-Ra, O, S or C=O; Y is CH2, N-Ra, O, S or C=O, with the proviso that at least one of X or Y is CH2, and preferably both of X and Y are CH2; Ra is H, an optionally substituted C1-C12 alkyl, preferably an optionally substituted C1-C6alkyl including a C3-C6 cyclic alkyl group, or an optionally substituted aryl group, preferably an optionally substituted phenyl group; Rb is H, an optionally substituted C1-C12 alkyl, preferably an optionally substituted C1-C6 acyclic or a a C3-C6 cyclic alkyl group, CHO, N(Me)O, CO(S)Ra or the group of Formula (III). Where Rc and Rd are each independently H, F, C1, an optionally substituted C1-C20 alkyl, preferably an optionally substituted C1-C12 alkyl, more preferably a C1-C6 alkyl, and an optionally substituted aryl group, or together Rc and Rd form an optionally substituted carbocyclic or optionally substituted heterocyclic ring; R1 is OH, OR, NR'R", NHC(=O)R, NHSO2R; R2 is H, F, C1, an optionally substituted C1-C20 alkyl, preferably an optionally substituted C1-C6 alkyl, an optionally substituted aryl group or a =O group (which establishes a carbonyl group with the carbon to which =O is attached; R3 is H, OH, F, C1, Br, I, Cl, an optionally substituted C1-C20 alkyl, alkenyl or alkynyl ("hydrocarbyl") group, preferably an optionally substituted C1-C6 alkyl, or an optionally substituted aryl, such that the carbon to which R3 is attached has an R or S configuration; R is H, an optionally substituted C1-C20 alkyl, preferably an optionally substituted C1-C6 alkyl, or an optionally substituted aryl group, R' and R" are each independently H, an optionally substituted C1-C20 alkyl group, preferably an optionally substituted C1-C6 alkyl, or an optionally substituted aryl group; or together R' and R" form an optionally substituted heterocyclic, preferably a 4 to 7 membered optionally substituted heterocyclic group or an optionally substituted heteroaryl ring with the nitrogen to which R' and R" are attached; and wherein said compound is free from a metal catalyst.
Concise enantio- and diastereoselective total syntheses of fumagillol, RK-805, FR65814, ovalicin, and 5-demethylovalicin
Yamaguchi, Junichiro,Toyoshima, Maya,Shoji, Mitsuru,Kakeya, Hideaki,Osada, Hiroyuki,Hayashi, Yujiro
, p. 789 - 793 (2007/10/03)
(Chemical Equation Presented) L-Proline-mediated α-aminoxylation is a key step in the enantio- and diastereoselective total syntheses of fumagillin, ovalicin, and related compounds (see scheme). These compounds contain a cyclohexane ring, two epoxides, an
Novel preparation of (-)-4-hydroxycyclohex-2-enone: Reaction of 4-hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone with some thiols
Bickley, Jamie F.,Evans, Paul,Meek, Alastair,Morgan, Ben S.,Roberts, Stanley M.
, p. 355 - 362 (2007/10/03)
A new route to (R)-4-hydroxycyclohex-2-enone from cyclohexanedione monoketal (27% yield) commences with reaction of the ketal with nitrosobenzene catalysed by l-proline. 4-Hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone react with thiols to afford
A highly selective, organocatalytic route to chiral 1,2-oxazines from ketones
Kumarn, Sirirat,Shaw, David M.,Ley, Steven V.
, p. 3211 - 3213 (2008/09/18)
A sequential, organocatalysed asymmetric reaction to access chiral 1,2-oxazines from achiral ketone starting materials is reported, which proceeds in moderate to good yields and excellent enantioselectivity. The Royal Society of Chemistry 2006.
Direct amino acid-catalyzed asymmetric desymmetrization of meso-compounds: Tandem aminoxylation/O-N bond heterolysis reactions
Ramachary, Dhevalapally B.,Barbas III, Carlos F.
, p. 1577 - 1580 (2007/10/03)
(Chemical Equation Presented) A practical organocatalytic process for the synthesis of optically active, highly substituted α-hydroxy-ketones was achieved through asymmetric desymmetrization (ADS) of prochiral ketones. The ADS and O-N bond reduction reaction of prochiral ketone with nitrosobenzene in the presence of a catalytic amount of chiral amine or amino acid produced the tandem ADS/O-N bond reduced products as single diastereomers with good yields and excellent enantiomeric excesses.
Bronsted acid catalysis of achiral enamine for regio- and enantioselective nitroso aldol synthesis
Momiyama, Norie,Yamamoto, Hisashi
, p. 1080 - 1081 (2007/10/03)
Two types of chiral Bronsted acid catalysts have been shown to catalyze regio- and enantioselective nitroso aldol synthesis between nitrosobenzene and achiral enamine. The combination of Bronsted acidity and amine moiety of enamine realizes complete regioselectivity with high enantioselectivity. After a survey of Bronsted acid catalysts, 1-naphthyl glycolic acid is found to be optimal in the O-nitroso aldol pathway, while 1-naphthyl TADDOL is the best catalyst for the N-nitroso aldol pathway. This is based on our finding on the control of regioselectivity by changing the amine moiety of enamine and the choice of Bronsted acidity. Copyright
Novel organic catalysts for the direct enantioselective α-oxidation of carbonyl compounds
Sundén, Henrik,Dahlin, Nils,Ibrahem, Ismail,Adolfsson, Hans,Córdova, Armando
, p. 3385 - 3389 (2007/10/03)
The proline-derived N-sulfonylcarboxamide-catalyzed direct enantioselective α-oxidation of ketones and aldehydes with nitrosobenzene is presented. The reactions proceed smoothly furnishing the corresponding α-aminoxylated compounds in good yields with up to >99% ee. The proline-derived N-sulfonylcarboxamides were also found to be excellent catalysts for the direct enantioselective nitroso Diels-Alder-type reaction between nitrosobenzene and α,β-unsaturated cyclic ketones yielding the corresponding bicyclic Diels-Alder adduct products with up to >99% ee. The proline-derived N-sulfonylcarboxamides represent a readily available and highly modular novel type of organic catalyst.
The direct catalytic asymmetric α-aminooxylation reaction: Development of stereoselective routes to 1,2-diols and 1,2-amino alcohols and density functional calculations
Cordova, Armando,Sunden, Henrik,Bogevig, Anders,Johansson, Mikael,Himo, Fahmi
, p. 3673 - 3684 (2007/10/03)
Proline-catalyzed direct asymmetric α-aminooxylation of ketones and aldehydes is described. The proline-catalyzed reactions between unmodified ketones or aldehydes and nitrosobenzene proceeded with excellent diastereo- and enantioselectivities. In all cases tested, the corresponding products were isolated with > 95% ees. Methyl alkyl ketones were regiospecifically oxidized at the methylene carbon atom to afford enantiomerically pure α-aminooxylated ketones. In addition, cyclic ketones could be α,α′-dioxidized with remarkably high selectivity, furnishing the corresponding diaminooxylated ketones with > 99% ees. The reaction mechanism of the proline-catalyzed direct asymmetric α-aminooxylation was investigated, and we performed density functional theory (DFT) calculations in order to investigate the nature of the plausible transition states further. We also screened other organocatalysts for the asymmetric α-oxidation reaction and found that several proline derivatives were also able to catalyze the transformation with excellent enantioselectivities. Moreover, stereoselective routes for the synthesis of monoprotected vicinal diols and hydroxyketones were found. In addition, short routes for the direct preparation of enantiomerically pure epoxides and 1,2-amino alcohols are presented. The direct catalytic α-oxidation is also a novel route for the stereoselective preparation of β-adrenoreceptor antagonists.
