- Iron-Catalyzed Highly Enantioselective Hydrogenation of Alkenes
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Here, we reported for the first time an iron-catalyzed highly enantioselective hydrogenation of minimally functionalized 1,1-disubstituted alkenes to access chiral alkanes with full conversion and excellent ee. A novel chiral 8-oxazoline iminoquinoline ligand and its iron complex have been designed and synthesized. This protocol is operationally simple by using 1 atm of hydrogen gas and shows good functional group tolerance. A primary mechanism has been proposed by the deuterium-labeling experiments.
- Lu, Dongpo,Lu, Peng,Lu, Zhan,Ren, Xiang,Sun, Yufeng,Xu, Haofeng
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p. 12433 - 12438
(2021/08/23)
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- Method for preparing chiral alkyl compound by catalyzing asymmetric hydrogenation reaction of olefin with iron complex catalyst
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The invention discloses a method for preparing a chiral alkyl compound by catalyzing asymmetric hydrogenation reaction of olefin with an iron complex catalyst, which comprises the steps of by taking disubstituted olefin as shown in a formula I defined in
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Paragraph 0148-0150
(2021/05/29)
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- Method for preparing chiral alkyl compound through asymmetric catalytic hydrogenation of E/Z mixed or single-configuration trisubstituted olefin
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The invention discloses a method for preparing a chiral alkyl compound through asymmetric catalytic hydrogenation of an E/Z mixed or single-configuration trisubstituted olefin. The method comprises following steps: taking a trisubstituted olefin represent
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Paragraph 0157-0159
(2020/01/14)
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- Method for synthesizing alkyne through catalytic asymmetric cross coupling (by machine translation)
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The invention belongs to the field of, asymmetric synthesis, and discloses a method for catalyzing asymmetric cross- coupling to synthesize: an alkyne, and the L method comprises, the following steps, of A: preparing B a cuprous, salt and C a: ligand; preparing a catalyst; adding a base; reacting the compound with the compound with the compound; and reacting the compound with the compound. Of these, one of them, X is selected from the group consisting of, R halogens. 1 Optionally substituted heteroarylsulfonylcyanamide groups selected from the, group consisting, of optionally substituted, phenyl groups In-flight vehicle, R6 Trialkyl silyl groups or alkyl radicals, R2 Cycloalkyl radicals optionally substituted with an, optionally substituted alkyl, (CH radical2 )n R4 Multi,layer chain, n=0-10,R saw blade4 A group selected, from, the group consisting of phenyl, alkenyl, aralkynyls, noonyloxy,and, noonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylphenyl disiloxy-radicals. R3 A ligand, selected from hydrogen or any of the functional groups, is selected from the group consisting of, hydrogen and any L other functional group. The method, R disclosed by the, A invention has the, advantages of good catalytic, R ’ effect, wide application range. and high catalytic efficiency, and the, method disclosed by the, invention has the. advantages of good catalytic effect, wide application range and high catalytic efficiency. (by machine translation)
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Paragraph 1062; 1074-1076
(2020/01/12)
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- A asymmetric catalytic synthesis of (R)- 4, 7 - dimethyl - 1 - Tetralone method
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The invention discloses a method for asymmetrically catalyzing and synthesizing (R)-4, 7-dimethyl-1-tetralone. According to the method, an asymmetrical Kumada cross coupling reaction is conducted on racemization 2-halogenated propionate ester catalyzed by bis oxazoline/ cobalt and a methyl phenyl grignard reagent, and (S)-P-toluene propionate ester 2 is firstly generated; then, (S)-P-toluene propionate ester 2 is reduced to (S)-P-toluene propyl alcohol 3 through diisobutylaluminium hydride (DIBAL-H), and then (R)-4-p-methylphenyl-1-amylene 5 is obtained through bromine generation and coupling with and vinyl grignard reagent; next, a hydroboration-oxidation reaction and a Dess-Martin oxidizing reaction are sequentially conducted, and (R)-4-p-methylphenyl valeraldehyde 6 is obtained; finally, oxidation is conducted through silver oxide, an intramolecular Fourier acyl reaction is conducted, and (R)-4,7-dimethyl-1-tetralone is obtained in a ring-closure synthesis mode. The synthesis route is simple and concise, 8 reactions are conducted in all, the total yield is 27%, and the optical purity of a product is 90%.
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- A asymmetric catalytic synthesis (S)- aryl curcumene method
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The invention discloses a method for asymmetrically catalyzing and synthesizing (S)-curcumene. According to the method, racemization 2-halogenated propionate ester serves as a starting material, under the catalysis of bis oxazoline/ cobalt, an asymmetrica
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- Asymmetric synthesis of (R)-ar-curcumene, (R)-4,7-dimethyl-l-tetralone, and their enantiomers via cobalt-catalyzed asymmetric Kumada cross-coupling
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An efficient and concise asymmetric synthesis of (R)-(+)-ar-curcumene, (R)-4,7-dimethyl-l-tetralone, and their enantiomers was accomplished. The key step to construct the stereogenic benzylmethyl centers of these natural products is the cobalt-catalyzed a
- Wu, Lin,Zhong, Jiang-Chun,Liu, Shi-Kuo,Liu, Fei-Peng,Gao, Zi-Dong,Wang, Min,Bian, Qing-Hua
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- Iridium-catalyzed asymmetric hydrogenation of 3,3-disubstituted allylic alcohols in ethereal solvents
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Ir-phosphinomethyl-oxazoline complexes have been identified as efficient, highly enantioselective catalysts for the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols. In contrast to other N,P ligand complexes, which require weakly coordinating solvents, such as dichloromethane, these catalysts perform well in more ecofriendly THF or 2-MeTHF. Their synthetic potential was demonstrated with the formal total synthesis of four bisabolane sesquiterpenes. Particularly high enantioselectivity values in the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols have been achieved with Ir-phosphinomethyloxazoline catalysts. In contrast to other N,P-ligand complexes, which require weakly coordinating solvents, such as CH 2Cl2, these catalysts perform well in more ecofriendly THF or 2-MeTHF (see scheme; CODa =a 1,5-cyclooctadiene). Copyright
- Bernasconi, Maurizio,Ramella, Vincenzo,Tosatti, Paolo,Pfaltz, Andreas
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p. 2440 - 2444
(2014/03/21)
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- Enantioselective copper-catalyzed conjugate addition of trimethylaluminum to β,γ-unsaturated α-ketoamides: Efficient access to γ-methyl-substituted carbonyl compounds
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Picture perfect: By using the reagent trimethylaluminium and β,γ-unsaturated α-ketoamides, 1,4-adducts were obtained with perfect 1,4-regioselectivity and good to excellent yields and ee values. The potential synthetic utility of the methodology was highl
- Goncalves-Contal, Sylvie,Gremaud, Ludovic,Alexakis, Alexandre
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p. 12701 - 12704
(2013/12/04)
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- Enantioselective iridium-catalyzed hydrogenation of β,γ- unsaturated carboxylic acids: An efficient approach to chiral 4-alkyl-4-aryl butanoic acids
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Chiral acids: A highly enantioselective iridium-catalyzed hydrogenation of β,γ-unsaturated carboxylic acids is developed for the preparation of chiral 4-alkyl-4-aryl butanoic acids (see scheme). Copyright
- Song, Song,Zhu, Shou-Fei,Yang, Shuang,Li, Shen,Zhou, Qi-Lin
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p. 2708 - 2711
(2012/04/17)
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- Protecting group free formal total synthesis of the antitubercular agent erogorgiaene
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The formal total synthesis of the antitubercular agent erogorgiaene was achieved in 12 steps by using a protecting group free strategy. The synthesis involves an enamine-mediated 1,4-addition, an aldol condensation, dehydrogenation, Wittig olefination, in
- Yadav, Jhillu S.,Thirupathaiah, Bodakuntla,Al Khazim Al Ghamdi, Ahmad
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p. 2072 - 2076
(2012/05/05)
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- trans-directing ability of the amide group: Enabling the enantiocontrol in the synthesis of 1,1-dicarboxy cyclopropanes. Reaction development, scope, and synthetic applications
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(Chemical Equation Presented) In this article, we describe our efforts toward the enantioselective formation of 1,1-cyclopropane diesters via the metal-catalyzed cyclopropanation of olefins. The strategies envisioned to achieve such a goal are discussed a
- Marcoux, David,Goudreau, Sebastien R.,Charette, Andre B.
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supporting information; experimental part
p. 8939 - 8955
(2010/03/02)
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- An aldol approach to the synthesis of the anti-tubercular agent erogorgiaene
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A total synthesis of erogorgiaene is described in 16 steps. The synthesis relies upon a highly diastereoselective intramolecular Friedel-Crafts reaction of an oxetane derived via an asymmetric syn aldol coupling.
- Yadav,Basak,Srihari
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p. 2841 - 2843
(2007/10/03)
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- Enantioselective synthesis of (+)-nuciferal, (+)-(E)-nuciferol and (+)-α-curcumene by chiral hydrogenesterification reaction
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Using chiral hydrogenesterification reaction as the key step, the stereoselective synthesis of (+)-nuciferal 1, (+)-(E)-nuciferol 2 and (+)-a-curcumene 3 has been achieved.
- Du, Zhenfing,Yue, Guoren,Ma, Junying,She, Xuegong,Wu, Tongxing,Pan, Xinfu
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p. 427 - 429
(2007/10/03)
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- Enantiodivergent Route to the Aromatic Bisabolane Sesquiterpenes by Regio- and Stereo-controlled Epoxide Opening
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An enantiodivergent route to aromatic bisabolane sesquiterpenes from a single chiral precursor has been established by employing regio- and stereo-controlled epoxide opening as the key step.
- Takano, Seiichi,Yanase, Masashi,Sugihara, Takumichi,Ogasawara, Kunio
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p. 1538 - 1540
(2007/10/02)
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- THE FIRST STEREOSELECTIVE SYNTHESIS OF (+)-NUCIFEROL AND (+)-NUCIFERAL
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Using (S)-benzyl 2,3-epoxypropyl ether (1), the first stereoselective synthesis of (+)-nuciferol (14) and (+)-nuciferal (16) has been achieved.Employing the same methodology an enantioselective synthesis of (+)-α-curcumene (17) is also described.
- Takano, Seiichi,Goto, Emiko,Ogasawara, Kunio
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p. 5567 - 5570
(2007/10/02)
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