- SYNTHESIS AND APPLICATION OF CHIRAL SUBSTITUTED POLYVINYLPYRROLIDINONES
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Chiral polyvinylpyrrolidinone (CSPVP), complexes of CSPVP with a core species, such as a metallic nanocluster catalyst, and enantioselective oxidation reactions utilizing such complexes are disclosed. The CSPVP complexes can be used in asymmetric oxidation of diols, enantioselective oxidation of alkenes, and carbon-carbon bond forming reactions, for example. The CSPVP can also be complexed with biomolecules such as proteins, DNA, and RNA, and used as nanocarriers for siRNA or dsRNA delivery.
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Paragraph 0046; 0047
(2020/11/24)
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- Synthesis of cyclic 1,3-diols as scaffolds for spatially directed libraries
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A useful design element in small molecule libraries is spatial diversity, in which binding moieties are systematically directed toward different regions of three-dimensional space. One way of achieving this is through the use of conformationally diverse scaffolds onto which various binding moieties can be placed. Such scaffolds can represent synthetic challenges of their own. In this paper, we describe a new route to chiral, cyclic 1,3-diol building blocks that features silylated dithianes as relay linchpins. These diols are subsequently used for the construction of a 24-compound pilot library bearing two amino acid residues.
- Singh, Gurpreet,Aubé, Jeffrey
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supporting information
p. 4299 - 4303
(2016/05/24)
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- Chiral-Substituted Poly-N-vinylpyrrolidinones and Bimetallic Nanoclusters in Catalytic Asymmetric Oxidation Reactions
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A new class of poly-N-vinylpyrrolidinones containing an asymmetric center at C5 of the pyrrolidinone ring were synthesized from l-amino acids. The polymers, particularly 17, were used to stabilize nanoclusters such as Pd/Au for the catalytic asymmetric oxidations of 1,3- and 1,2-cycloalkanediols and alkenes, and Cu/Au was used for C-H oxidation of cycloalkanes. It was found that the bulkier the C5 substituent in the pyrrolidinone ring, the greater the optical yields produced. Both oxidative kinetic resolution of (±)-1,3- and 1,2-trans-cycloalkanediols and desymmetrization of meso cis-diols took place with 0.15 mol % Pd/Au (3:1)-17 under oxygen atmosphere in water to give excellent chemical and optical yields of (S)-hydroxy ketones. Various alkenes were oxidized with 0.5 mol % Pd/Au (3:1)-17 under 30 psi of oxygen in water to give the dihydroxylated products in >93% ee. Oxidation of (R)-limonene at 25 °C occurred at the C-1,2-cyclic alkene function yielding (1S,2R,4R)-dihydroxylimonene 49 in 92% yield. Importantly, cycloalkanes were oxidized with 1 mol % Cu/Au (3:1)-17 and 30% H2O2 in acetonitrile to afford chiral ketones in very good to excellent chemical and optical yields. Alkene function was not oxidized under the reaction conditions. Mechanisms were proposed for the oxidation reactions, and observed stereo- and regio-chemistry were summarized.
- Hao, Bo,Gunaratna, Medha J.,Zhang, Man,Weerasekara, Sahani,Seiwald, Sarah N.,Nguyen, Vu T.,Meier, Alex,Hua, Duy H.
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supporting information
p. 16839 - 16848
(2017/01/10)
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- Lipophilic oligopeptides for chemo- and enantioselective acyl transfer reactions onto alcohols
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Inspired by the extraordinary selectivities of acylases, we envisioned the use of lipophilic oligopeptidic organocatalysts for the acylative kinetic resolution/desymmetrization of rac- and meso-cycloalkane-1,2-diols. Here we describe in a full account the discovery and development process from the theoretical concept to the final catalyst, including scope and limitations. Competition experiments with various alcohols and electrophiles show the full potential of the employed oligopeptides. Additionally, we utilized NMR and IR-spectroscopic methods as well as computations to shed light on the factors responsible for the selectivity. The catalyst system can be readily modified to a multicatalyst by adding other catalytically active amino acids to the peptide backbone, enabling the stereoselective one-pot synthesis of complex molecules from simple starting materials.
- Mueller, Christian E.,Zell, Daniela,Hrdina, Radim,Wende, Raffael C.,Wanka, Lukas,Schuler, Soeren M. M.,Schreiner, Peter R.
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p. 8465 - 8484
(2013/09/24)
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- Kinetic resolution of chiral auxiliaries with C2-symmetry by lipase-catalyzed alcoholysis and aminolysis
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Three cyclic diols, 1,2-cyclohexanediol (1), 1,3-cyclohexanediol (2), and 1,3-cyclopentanediol (3), two acyclic unsaturated diols, 1,5-hexadiene-3,4-diol (4) and 1,7-octadiyne-3,6-diol (5), and a cyclic diamine, 1,2-cyclohexanediamine (6), have been kinetically resolved in alcoholysis and aminolysis reactions, catalyzed by Candida antarctica component B lipase, using S-ethyl thiooctanoate or ethyl octanoate as acyl donors. Acceptable stereoselectivity was achieved in most cases. Acta Chemica Scandinavica 1996.
- Mattson, Anders,Orrenius, Christian,Oehrner, Niklas,Unelius, C. Rikard,Hult, Karl,Norin, Torbjoern
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p. 918 - 921
(2007/10/03)
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