- Preparation method of chiral 1, 4-diphenyl-2-hydroxy-1, 4-dibutanone compound
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The invention provides a preparation method of a chiral 1, 4-diphenyl-2-hydroxyl-1, 4-dibutanone compound. The method comprises the following steps: in the presence of a chiral metal compound, mixing silyl enol ether and phenylacetaldehyde monohydrate or substituted phenylacetaldehyde monohydrate in a solvent and performing action to obtain the chiral 1, 4-diphenyl-2-hydroxy-1, 4-dibutanone compound, wherein the reaction equation is as shown in the formula 1; R1 of silyl enol ether is of a phenyl or furan structure, a substituent R2 in substituted phenyl glyoxal monohydrate is selected from one or more of hydrogen atoms, halogen, methyl, methoxyl, nitryl and trifluoromethyl, and the substituent is at the ortho-position, meta-position or para-position of a benzene ring. The chiral metal compound can efficiently and highly enantioselectively catalyze the asymmetric Mukaiyama aldol reaction of the phenylacetaldehyde monohydrate compound, a new method for synthesizing the 1, 4-diphenyl-2-hydroxy-1, 4-dibutanone compound is provided, the problem that conditions are harsh in the original reaction is solved, and the chiral metal compound is more environmentally friendly.
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Paragraph 0121; 0124; 0126
(2021/06/22)
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- Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions
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The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.
- Novacek, Johanna,Roiser, Lukas,Zielke, Katharina,Robiette, Rapha?l,Waser, Mario
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supporting information
p. 11422 - 11428
(2016/08/03)
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- Organocatalytic enantioselective α-hydroxymethylation of aldehydes: Mechanistic aspects and optimization
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Further studies of the direct enantioselective α-hydroxymethylation of aldehydes employing the α,α-diarylprolinol trimethylsilyl ether class of organocatalysts are described. This process has proven efficient for access to β-hydroxycarboxylic acids and δ-hydroxy-α,β-unsaturated esters from aldehydes in generally good yields, excellent enantioselectivity, and compatibility with a broad range of functional groups in the aldehyde. The goal of these studies was to identify the critical reaction variables that influence the yield and enantioselectivity of the α-hydroxymethylation process such as catalyst structure, pH of the medium, purity of the reactants and reagents particularly with respect to the presence of acidic impurities, and the nature of the buffer, along with the standard variables including solvent, time, temperature and mixing efficiency. The previously identified intermediate lactol has been further characterized and its reactivity examined. These studies have led to identification of the most critical variables translating directly into improved substrate scope, reproducibility, enantioselectivity, and yields.
- Boeckman, Robert K.,Biegasiewicz, Kyle F.,Tusch, Douglas J.,Miller, John R.
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p. 4030 - 4045
(2015/05/05)
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- NOVEL NI COMPLEX AND ITS DERIVATIVES, PRODUCING METHOD, AND THE USE THEREOF AS AN ANTIOXIDANT
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The present invention relates to a novel nickel complex and its derivatives, which mimic the active site of Ni-containing superoxide dismutase (NiSOD). The five-coordinate Ni(II) and Ni(III) complexes or their derivatives, and six-coordinate derivatives have the following structures of formula (I) and (II): The nickel complexes and their derivatives of the invention act as anti-oxidants or free radical scavengers. The invented nickel complexes can be used in the preparation of medicines, health foods or cosmetics for human, animals and plants, or can be used in environmental or soil protection.
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Paragraph 0037
(2013/12/04)
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- Enantioselective michael addition to α,β-Unsaturated aldehydes: Combinatorial catalyst preparation and screening, reaction optimization and mechanistic studies
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Shortcut to chiral catalysts: An efficient combinatorial strategy based on back reaction screening by ESI-MS allows rapid evaluation of organocatalysis for the asymmetric Michael addition to α,β-unsaturated aldehydes (see scheme). An unexpected nonlinear effect has been observed in this reaction, resulting from a double nucleophilic-electrophilic activation mechanism involving two catalyst molecules "Chemical Equation Presented"
- Fleischer, Ivana,Pfaltz, Andreas
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supporting information; experimental part
p. 95 - 99
(2010/03/26)
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- A Practical Enantioselective Synthesis of α,α-Diaryl-2-pyrrolidinemethanol. Preparation and Chemistry of the Corresponding Oxazaborolidines
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A practical two-step enantioselective synthesis of α,α-diaryl-2-pyrrolidinemethanols (1) from proline, based on the addition of aryl Grignard reagents to proline-N-carboxanhydride (3), is reported.An investigation into the chemistry of the corresponding B-alkyl- and B-aryloxazaborolidines (2) led to the development of a reliable procedure for their preparation.
- Mathre, David J.,Jones, Todd K.,Xavier, Lyndon C.,Blacklock, Thomas J.,Reamer, Robert A.,et al.
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p. 751 - 762
(2007/10/02)
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