scholarly journals Chiral Epoxides via Borane Reduction of 2-Haloketones Catalyzed by Spiroborate Ester: Application to the Synthesis of Optically Pure 1,2-Hydroxy Ethers and 1,2-Azido Alcohols

2011 ◽  
Vol 76 (6) ◽  
pp. 1883-1886 ◽  
Author(s):  
Kun Huang ◽  
Haiyang Wang ◽  
Viatcheslav Stepanenko ◽  
Melvin De Jesús ◽  
Carilyn Torruellas ◽  
...  
Keyword(s):  
Chiral Epoxides ◽  
Borane Reduction ◽  
Optically Pure

ChemInform Abstract: Chiral Epoxides via Borane Reduction of 2-Haloketones Catalyzed by Spiroborate Ester: Application to the Synthesis of Optically Pure 1,2-Hydroxy Ethers and 1,2-Azido Alcohols.

ChemInform ◽  
2011 ◽  
Vol 42 (24) ◽  
pp. no-no
Author(s):  
Kun Huang ◽  
Haiyang Wang ◽  
Viatcheslav Stepanenko ◽  
Melvin De Jesus ◽  
Carilyn Torruellas ◽  
...  
Keyword(s):  
Chiral Epoxides ◽  
Borane Reduction ◽  
Optically Pure

Preparation of highly optically pure homochiral sulfide-containing alcohols via oxazaborolidine-catalyzed asymmetric borane reduction of ketones

Chirality ◽  
2004 ◽  
Vol 16 (6) ◽  
pp. 341-346 ◽  
Author(s):  
Jiaxi Xu ◽  
Tiezheng Wei ◽  
Jiakun Xia ◽  
Qihan Zhang ◽  
Hesong Wu
Keyword(s):  
Borane Reduction ◽  
Optically Pure ◽  
Reduction Of Ketones

New Camphor-Derived Selenonium Ylides: Enantioselective Synthesis of Chiral Epoxides

2005 ◽  
Vol 58 (10) ◽  
pp. 749 ◽  
Author(s):  
Xin-Liang Li ◽  
Yi Wang ◽  
Zhi-Zhen Huang
Keyword(s):  
Enantioselective Synthesis ◽  
One Pot ◽  
Chiral Epoxides ◽  
Optically Pure

Optically pure selenonium salts 3 as the precursors of two new chiral selenonium ylides 4 can be synthesized stereoselectively from natural d-camphor in good yields. It is found that the reaction of the selenonium salt 3b, an aldehyde, and potassium tert-butoxide can take place smoothly in ‘one-pot’ via the formation of selenonium ylide 4b, to give chiral trans-diaryl epoxides 5 in good yields with good diastereoselectivities and enantioselectivities.

scholarly journals Production of Enantiopure Chiral Epoxides with E. coli Expressing Styrene Monooxygenase

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1514
Author(s):  
Dominika Gyuranová ◽  
Radka Štadániová ◽  
Zuzana Hegyi ◽  
Róbert Fischer ◽  
Martin Rebroš
Keyword(s):  
High Cell Density ◽  
Enantiomeric Excess ◽  
Building Blocks ◽  
E Coli ◽  
Styrene Monooxygenase ◽  
Chiral Compounds ◽  
Chiral Epoxides ◽  
Optically Pure ◽  
Epoxidation Of Alkenes ◽  
Excellent Stability

Styrene monooxygenases are a group of highly selective enzymes able to catalyse the epoxidation of alkenes to corresponding chiral epoxides in excellent enantiopurity. Chiral compounds containing oxirane ring or products of their hydrolysis represent key building blocks and precursors in organic synthesis in the pharmaceutical industry, and many of them are produced on an industrial scale. Two-component recombinant styrene monooxygenase (SMO) from Marinobacterium litorale was expressed as a fused protein (StyAL2StyB) in Escherichia coli BL21(DE3). By high cell density fermentation, 35 gDCW/L of biomass with overexpressed SMO was produced. SMO exhibited excellent stability, broad substrate specificity, and enantioselectivity, as it remained active for months and converted a group of alkenes to corresponding chiral epoxides in high enantiomeric excess (˃95–99% ee). Optically pure (S)-4-chlorostyrene oxide, (S)-allylbenzene oxide, (2R,5R)-1,2:5,6-diepoxyhexane, 2-(3-bromopropyl)oxirane, and (S)-4-(oxiran-2-yl)butan-1-ol were prepared by whole-cell SMO.

A Peptoid with Extended Shape in Water

2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Biomolecular Recognition ◽  
Biological Application ◽  
New Class ◽  
Proteolytic Resistance ◽  
Pharmacokinetic Properties ◽  
Optically Pure ◽  
Three Dimensional Space

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>

scholarly journals Altering the Stereoselectivity of Whole-Cell Biotransformations via the Physicochemical Parameters Impacting the Processes

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 781
Author(s):  
Agnieszka Raczyńska ◽  
Joanna Jadczyk ◽  
Małgorzata Brzezińska-Rodak
Keyword(s):  
Culture Conditions ◽  
Biologically Active ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
Chiral Compounds ◽  
Physicochemical Factors ◽  
Pure Compounds ◽  
Genetic Level ◽  
Prochiral Ketones ◽  
Optically Pure

The enantioselective synthesis of organic compounds is one of the great challenges in organic synthetic chemistry due to its importance for the acquisition of biologically active derivatives, e.g., pharmaceuticals, agrochemicals, and others. This is why biological systems are increasingly applied as tools for chiral compounds synthesis or modification. The use of whole cells of “wild-type” microorganisms is one possible approach, especially as some methods allow improving the conversion degrees and controlling the stereoselectivity of the reaction without the need to introduce changes at the genetic level. Simple manipulation of the culture conditions, the form of a biocatalyst, or the appropriate composition of the biotransformation medium makes it possible to obtain optically pure products in a cheap, safe, and environmentally friendly manner. This review contains selected examples of the influence of physicochemical factors on the stereochemistry of the biocatalytic preparation of enantiomerically pure compounds, which is undertaken through kinetically controlled separation of their racemic mixtures or reduction of prochiral ketones and has an effect on the final enantiomeric purity and enantioselectivity of the reaction.

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