- Catalytic asymmetric bromochlorination of aromatic allylic alcohols promoted by multifunctional Schiff base ligands
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It was found that the tridentate O,N,O-type Schiff base ligand bearing suitable substituents was a highly effective promoter in the catalytic asymmetric bromochlorination reaction, in which the corresponding aromatic bromochloroalcohols with vicinal halogen-bearing stereocenters were formed with perfect regioselectivity, with moderate to excellent enantioselectivities (up to 93% ee), and with good yields and chemoselectivities.
- Huang, Wei-Sheng,Chen, Li,Zheng, Zhan-Jiang,Yang, Ke-Fang,Xu, Zheng,Cui, Yu-Ming,Xu, Li-Wen
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supporting information
p. 7927 - 7932
(2016/08/30)
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- Enantioselective syntheses of β-amino alcohols catalyzed by recyclable chiral Fe(III) metal complex
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An efficient asymmetric desymmetrization of meso-epoxides with anilines catalysed by a series of simple and environmentally benign in situ generated Fe(iii) complexes based on chiral tridentate ligands L1-L7 with achiral and chiral l
- Tak, Rajkumar,Kumar, Manish,Kureshy, Rukhsana I.,Choudhary, Manoj Kumar,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
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p. 7693 - 7700
(2016/07/13)
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- Synthesis of a chiral fluorescence active probe and its application as an efficient catalyst in the asymmetric Friedel-Crafts alkylation of indole derivatives with nitroalkenes
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Novel chiral Zn(ii) complexes were synthesized and these complexes showed fluorescence behaviour. These chiral Zn(ii) complexes were tested in the asymmetric Friedel-Crafts alkylation reaction of indole derivatives with nitroalkenes. In all the cases, the
- More, Ganesh Vasant,Bhanage, Bhalchandra Mahadeo
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p. 1514 - 1520
(2015/04/27)
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- Screening of a library of hemisalen ligands in asymmetric H-transfer: Reduction of aromatic ketones in water
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A library of chiral hemisalen ligands (30) was realized. The ligands were synthesized by the condensation of salicylaldehyde derivatives with amino-alcohols (amino-indanol or substituted amino-ethanol) and characterized. These ligands associated with ruthenium (II) precursors were tested on the asymmetric transfer hydrogenation (ATH) of aromatic ketones by sodium formate in water. The different substituent pattern on the ligand (electronic and hindrance effects on different positions) as well as the ruthenium precursor were investigated. The best compromise in terms of conversion and chiral induction led to the complex [RuCl2(mesitylene)]2 coordinated to (1S,2R)-1-((E)-(3-(dimethyl(phenyl)silyl)-2-hydroxy-5-methoxy benzylidene) amino)-2,3-dihydro-1H-inden-2-ol (L25). It reduces acetophenone in 95% yield and 91% ee in 18 h at 30°C.
- Boukachabia, Mourad,Vriamont, Nicolas,Lambin, Dominique,Riant, Olivier,Aribi-Zouioueche, Louisa
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p. 403 - 412
(2014/05/06)
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- Synthesis of chiral ligands with multiple stereogenic centers and their application in titanium(iv)-catalyzed enantioselective desymmetrization of meso-epoxides
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New chiral ligands, (S,R,S)-1, (S,S,S)-1, (S,S,R)-1, (S,R,R)-1, (R,R,R)-1, (R,R,S)-1, (R,S,S)-1, (R,S,R)-1, (S,R,S)-2, (S,S)-3 and (R,S)-4 with diverse stereogenic centers arising from various diastereomeric combinations of aminoalcohol functionality with
- Kumar, Manish,Kureshy, Rukhsana I.,Ghosh, Debashis,Khan, Noor-UL H.,Abdi, Sayed H. R.,Bajaj, Hari C.
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p. 2336 - 2342
(2013/08/23)
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- Method for Producing Polyhydroxyalkanoates
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The invention relates to a process for preparing polyhydroxyalkanoates by polymerization of lactones of the general formula I, where the substituents and the index n have the meanings given in the description, in the presence of at least one catalyst of the formula (II) LIMaXam, where the substituents and indices have the meanings given in the description. The invention further relates to poly-3-hydroxybutyrates which have a novel property profile and are obtainable for the first time by means of this process, and also biodegradable polyester mixtures based on these poly-3-hydroxybutyrates.
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- Enantioselective synthesis of an atropisomeric diaryl ether
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(Chemical Equation Presented) Twisted ethers: Introduction of a bulky alkylsulfinyl substituent ortho to the C-O axis of a diaryl ether imposes a powerful conformational preference (see scheme). The preference persists upon oxidation of the sulfoxide to a sulfone, leading to dynamic thermodynamic resolution of the atropisomeric ether. This is the first enantioselective synthesis of an atropisomeric diaryl ether not forming part of a macrocyclic ring.
- Clayden, Jonathan,Worrall, Christopher P.,Moran, Wesley J.,Helliwell, Madeleine
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supporting information; experimental part
p. 3234 - 3237
(2009/02/08)
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- Exploring structural diversity in ligand design: The aminoindanol case
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A series of enantiopure ligands based on the aminoindanol scaffold, but differing in regio-and stereochemistry has been synthesized. These ligands have been conveniently derivatized and their catalytic efficiency in different enantioselective reactions has been screened to determine privileged candidates with respect to regio- and stereochemistry for each considered process. The nature of the amino substituent has been optimized for specific applications and this has led to the development of an efficient method for the preparation of bulky bicyclic amines by reductive amination.
- Rodriguez-Escrich, Sergi,Sola, Lluis,Jimeno, Ciril,Rodriguez-Escrich, Carles,Pericas, Miquel A.
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supporting information; experimental part
p. 2250 - 2260
(2009/10/06)
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- Asymmetric catalysis of hetero-ene reactions with tridentate Schiff base chromium(III) complexes
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Tridentate Schiff base chromium(III) complex 1 catalyzes the asymmetric hetero-ene reaction between aryl aldehydes and either 2-methoxypropene or 2-trimethylsilyloxypropene to provide a series of β-hydroxyenol ether products in high yields and enantiosele
- Ruck, Rebecca T.,Jacobsen, Eric N.
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p. 2882 - 2883
(2007/10/03)
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- Enantioselective sulfide oxidation with H2O2: A solid phase and array approach for the optimisation of chiral Schiff base-vanadium catalysts
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Two libraries of chiral Schiff base ligands were synthesised and screened in the vanadium-catalysed oxidation of alkyl aryl sulfides with hydrogen peroxide as terminal oxidant. The vanadium-chiral Schiff base complex 10, readily prepared from 3,5-diiodo-salicylaldehyde and (S)-tert-leucinol, was found to be highly enantioselective. Optically active sulfoxides could thus be obtained in good yields with up to 97% ee.
- Pelotier, Béatrice,Anson, Mike S.,Campbell, Ian B.,Macdonald, Simon J. F.,Priem, Ghislaine,Jackson, Richard F. W.
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p. 1055 - 1060
(2007/10/03)
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- Enantioselective ring opening of meso aziridines catalyzed by Tridentate Schiff base chromium(III) complexes.
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[formula: see text] A catalytic method for the enantioselective ring opening of meso aziridines by TMSN3 is described. Tridentate Schiff base chromium complexes derived from 1-amino-2-indanol were identified as the optimal catalysts.
- Li,Fernandez,Jacobsen
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p. 1611 - 1613
(2008/02/10)
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