- Oxidation of BINOLs by Hypervalent Iodine Reagents: Facile Synthesis of Xanthenes and Lactones
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Xanthene derivatives have broad applications in medicines, fluorescent probes, dyes, food additives, etc. Therefore, much attention was focused on developing the synthetic methods to prepare these compounds. Binaphthyl-based xanthene derivatives were prepared through the oxidation of BINOLs promoted by the hypervalent iodine reagent iodosylbenzene (PhIO). Nine-membered lactones were obtained through a similar oxidative reaction when iodoxybenzene (PhIO2) was used. Additionally, one-pot reactions of BINOLs, PhIO and nucleophiles such as alcohols and amines were also investigated to provide alkoxylated products and amides in good to excellent yields.
- Wirth, Thomas,Zhang, Huaiyuan
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supporting information
(2022/03/17)
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- First enantioselective total synthesis of altersolanol A
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The first enantioselective total synthesis of altersolanol A, a secondary metabolite from the endophytic fungi Stemphylium globuliferum and Alternaria solani, is described. The key step towards the tetrahydroanthraquinone core was an asymmetric Diels-Alder (D-A) cycloaddition promoted by (R)-3,3′-diphenyl-BINOL/boron Lewis acid with good to excellent yields and excellent diastereo- and enantioselectivity (>95 : 5 dr and 98 : 2 er).
- Mechsner, Bastian,Hen?en, Birgit,Pietruszka, J?rg
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supporting information
p. 7674 - 7681
(2018/11/02)
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- Chromatographic Resolution of α-Amino Acids by (R)-(3,3'-Halogen Substituted-1,1'-binaphthyl)-20-crown-6 Stationary Phase in HPLC
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Three new chiral stationary phases (CSPs) for high-performance liquid chromatography were prepared from R-(3,3'-halogen substituted-1,1'-binaphthyl)-20-crown-6 (halogen = Cl, Br and I). The experimental results showed that R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 (CSP-1) possesses more prominent enantioselectivity than the two other halogen-substituted crown ether derivatives. All twenty-one α-amino acids have different degrees of separation on R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6-based CSP-1 at room temperature. The enantioselectivity of CSP-1 is also better than those of some commercial R-(1,1'-binaphthyl)-20-crown-6 derivatives. Both the separation factors (α) and the resolution (Rs) are better than those of commercial crown ether-based CSPs [CROWNPAK CR(+) from Daicel] under the same conditions for asparagine, threonine, proline, arginine, serine, histidine and valine, which cannot be separated by commercial CR(+). This study proves the commercial usefulness of the R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 chiral stationary phase.
- Wu, Peng,Wu, Yuping,Zhang, Junhui,Lu, Zhenyu,Zhang, Mei,Chen, Xuexian,Yuan, Liming
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p. 1037 - 1042
(2017/07/25)
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- Enantioselective one-pot synthesis of dihydroquinolones via BINOL-derived Lewis acid catalysis
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A high-yielding and diastereoselective route to biologically significant 2-aryl- and 2-alkyl-3-amido dihydroquinolones has been developed in up to 90 : 10 e.r. by employing a novel Lewis acidic BINOL-derived copper(ii) catalyst.
- Knipe, Peter C.,Smith, Martin D.
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supporting information
p. 5094 - 5097
(2014/07/08)
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- Catalytic enantioselective amination of alcohols by the use of borrowing hydrogen methodology: Cooperative catalysis by iridium and a chiral phosphoric acid
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The catalytic asymmetric reduction of ketimines has been explored extensively for the synthesis of chiral amines, with reductants ranging from Hantzsch esters, silanes, and formic acid to H2 gas. Alternatively, the amination of alcohols by the use of borrowing hydrogen methodology has proven a highly atom economical and green method for the production of amines without an external reductant, as the alcohol substrate serves as the H2 donor. A catalytic enantioselective variant of this process for the synthesis of chiral amines, however, was not known. We have examined various transition- metal complexes supported by chiral ligands known for asymmetriC-Hydrogenation reactions, in combination with chiral Bronsted acids, which proved essential for the formation of the imine intermediate and the transfer-hydrogenation step. Our studies led to an asymmetric amination of alcohols to provide access to a wide range of chiral amines with good to excellent enantioselectivity.
- Zhang, Yao,Lim, Ching-Si,Boon Sim, Derek Sui,Pan, Hui-Jie,Zhao, Yu
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supporting information
p. 1399 - 1403
(2014/03/21)
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- Synthesis of TRIP and analysis of phosphate salt impurities
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The chiral phosphoric acid TRIP, a useful Brnsted acid catalyst, easily becomes contaminated with metal impurities in the form of phosphate salts during synthesis. This significantly reduces the content of free acid in the product which can hamper the cat
- Klussmann, Martin,Ratjen, Lars,Hoffmann, Sebastian,Wakchaure, Vijay,Goddard, Richard,List, Benjamin
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supporting information; experimental part
p. 2189 - 2192
(2010/10/21)
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- ASYMMETRIC-SYNTHESIS CATALYST BASED ON CHIRAL BROENSTED ACID AND METHOD OF ASYMMETRIC SYNTHESIS WITH THE CATALYST
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A compound usable as an asymmetric synthesis catalyst which can be easily synthesized without using any metal such as a lanthanoid group element; a method of asymmetric synthesis with the compound; and a chiral compound obtained by the asymmetric synthesis method. A Broensted acid is used as a catalyst in asymmetric synthesis, the chiral Broensted acid being represented by formula (1) below or formula (3) below. The asymmetric synthesis method employs the catalyst. Asymmetric synthesis with the catalyst gives a chiral compound.
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Page/Page column 16
(2010/11/08)
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- Compositions and methods for selectively binding amines or amino acid enantiomers over their counter-enantiomers
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Naphthyl crown ether ligand molecules containing at least two naphthyl groups that are covalently bonded to suitable solid supports and coated by hydrophobic organic solvents are disclosed. These compositions and associated methods are characterized by selectivity of desired amine or amino acid enantiomers over their counter-enantiomers and derivatives. The composition preferably has an α-value greater than or equal to 4. This allows for the separation of such enantiomers with nonchromatographic resin bed separations of three separation stages or less.
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Page column 13
(2010/11/30)
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- Chiral Mo-binol complexes: Activity, synthesis, and structure. Efficient enantioselective six-membered ring synthesis through catalytic metathesis
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A new class of chiral Mo-based complexes 2a and 2b, bearing functionalized chiral binol ligands, is disclosed. Mo complex 2a promotes the asymmetric ring-closing metathesis (ARCM) of various dienes and trienes to afford six-membered carbo- and heterocycle
- Zhu, S. Sherry,Cefalo, Dustin R.,La, Daniel S.,Jamieson, Jennifer Y.,Davis, William M.,Hoveyda, Amir H.,Schrock, Richard R.
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p. 8251 - 8259
(2007/10/03)
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- Host-Guest Complexation. 23. High Chiral Recognition of Amino Acid and Ester Guests by Hosts Containing One Chiral Element
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The chiral recognition properties of ten enantiomerically pure hosts toward the enantiomers of six different amino acids and their methyl esters have been examined.The hosts possessed the general structure (A)2D(OEOEO)2E, in which D is the chiral 1,1'-din
- Lingenfelter, David S.,Helgeson, Roger C.,Cram, Donald J.
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p. 393 - 406
(2007/10/02)
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