- Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
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Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
- Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
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supporting information
p. 2466 - 2474
(2019/03/11)
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- Enantioselective halogenative semi-pinacol rearrangement: A stereodivergent reaction on a racemic mixture
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An efficient, quantitative deracemization strategy for optically inactive allylic cycloalkanols has been achieved using the biphasic halogenative semi-pinacol reaction protocol. The resultant β-halo spiroketones, containing three contiguous stereogenic ce
- Romanov-Michailidis, Fedor,Pupier, Marion,Gune, Laure,Alexakis, Alexandre
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p. 13461 - 13464
(2015/02/19)
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- Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
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α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
- Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
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p. 10609 - 10616
(2012/11/07)
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- Lipase catalysed kinetic resolutions of 3-aryl alkanoic acids
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Hydrolase catalysed kinetic resolutions leading to a series of 3-aryl alkanoic acids (≥94% ee) are described. Hydrolysis of the ethyl esters with a series of hydrolases was undertaken to identify biocatalysts that yield the corresponding acids with excellent enantiopurity in each case. Steric and electronic effects on the efficiency and enantioselectivity of the biocatalytic transformation were also explored.
- Deasy, Rebecca E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
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- Asymmetric conjugate reduction of α,β-unsaturated ketones and esters with chiral rhodium(2,6-bisoxazolinylphenyl) catalysts
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New asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2- one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60°C in 95% ee and 98 % ee, respectively, by 1 mol % of catalyst loading. (EtO) 2MeSiH proved to be the best hydrogen donor of choice. tert-Butyl (E)-β-methylcinnamate and β-isopropylcinnamate could also be reduced to the corresponding dihydrocinnamate derivatives up to 98% ee.
- Kanazawa, Yoshinori,Tsuchiya, Yasunori,Kobayashi, Kazuki,Shiomi, Takushi,Itoh, Jun-Ichi,Kikuchi, Makoto,Yamamoto, Yoshihiko,Nishiyama, Hisao
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- NITROGENOUS CYCLIC COMPOUNDS AND PHARMACEUTICAL COMPOSITIONS CONTAINING THE SAME
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The present invention provides a novel compound having a superior calcium antagonism, in particular, a neuron-selective calcium antagonism. Namely, it provides a compound represented by the following formula, a salt thereof or a hydrate of them. In the formula, Ar indicates an optionally substituted 5- to 14-membered aromatic ring etc.; the ring A indicates any one ring selected from a piperazine, a homopiperazine, a piperidine and the like; the ring B indicates an optionally substituted C3-14 hydrocarbon ring etc.; E indicates a single bond, a group represented by the formula -CO-, etc.; X indicates a single bond, an oxygen atom etc.; R1 indicates a hydrogen atom, a halogen atom, a hydroxyl group etc.; and D1, D2, W1 and W2 are the same as or different from each other and each represents a single bond or an optionally substituted C1-6 alkylene chain.
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- 1,2-Secopyrethroids: Synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates
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A simple, elegant synthesis of (+/-) α-(RS)-cyano-3-phenoxybenzyl-4-methyl-3-phenyl/p-substituted-phenylpentanoates (I,XIV,XXI) has been described.
- Kher, S. M.,Kulkarni, G. H.
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p. 675 - 676
(2007/10/02)
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- Reaction of Grignard Reagents with Benzaldehyde, 2,2-Dimethylpropanal and Cinnamates of Chiral Alcohols in Chiral Solvents
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The asymmetric induction in a Grignard reaction carried out in (-)-1-isopropyl-2-methoxy-4-methylcyclohexane was higher than in the reaction carried out in (+)-1-methoxy-2-methylbutane.The chirality of the solvent contributed more than that of the reagent stereodifferentiation in the reaction of (+)-2-methylbutylmagnesium bromide with benzaldehyde in (+)-1-methoxy-2-methylbutane.
- Jalander, Lars,Strandberg, Rolf
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- Silyl Phosphites. XVIII. Versatile Utility of α-(Trimethylsilyloxy)-alkylphosphonates as Key Intermediates for Transformation of Aldehydes into Several Carbonyl Derivatives
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Carbonyl addition compounds of diethyl trimethylsilyl phosphite (DTMSP) with aldehydes were converted, by treatment with lithium diisopropylamide (LDA) followed by the successive alkylation and alkaline hydrolysis, to carbonyl derivatives involving aldehydes, unsymmetrical ketones, β,γ-unsaturated ketones, and carboxylic acids. β-Substituted carboxylic esters and γ-substituted lactones were prepared by use of the carbonyl addition compounds of DTMSP with α,β-unsaturated aldehydes.
- Sekine, Mitsuo,Nakajima, Masashi,Kume, Akiko,Hashizume, Akio,Hata, Tsujiaki
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p. 224 - 238
(2007/10/02)
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- Facile synthesis of β-alkyl-substituted esters from α,β-unsaturated aldehydes
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β-Alkyl-substituted carboxylates were synthesized in good yields from α,β-unsaturated aldehydes by using the 1:1 carbonyl adducts with diethyl bis (trimethylsilyl) phosphite.
- Hata, Tsujiaki,Nakajima, Masashi,Sekine, Mitsuo
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p. 2047 - 2050
(2007/10/13)
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