A5023524317- Asymmetric Synthesis and Catalysis
- Synthetic Organic Chemistry Methods
- Cyclopropane Reaction Mechanisms
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Metabolomics and Mass Spectrometry Studies
- Synthesis and Catalytic Reactions
- Oxidative Organic Chemistry Reactions
- Catalytic C–H Functionalization Methods
- Asymmetric Hydrogenation and Catalysis
- Chemical Synthesis and Reactions
- Sulfur-Based Synthesis Techniques
- Carbohydrate Chemistry and Synthesis
- Chemical Synthesis and Analysis
- Crystallography and molecular interactions
- Axial and Atropisomeric Chirality Synthesis
- Catalytic Cross-Coupling Reactions
- Synthesis and Biological Activity
- Diet and metabolism studies
- Synthesis of Indole Derivatives
- Radical Photochemical Reactions
- Chemical synthesis and alkaloids
- Traditional and Medicinal Uses of Annonaceae
- Catalytic Alkyne Reactions
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
Sungkyunkwan University
2016-2025
Suwon Research Institute
2014-2020
University of Jinan
2018
Kwangshin University
2007-2016
Korea Basic Science Institute
2007-2016
Chungnam National University
1999-2012
Wonkwang University
2011
Korea Institute of Oriental Medicine
2011
Korea University
2011
Samsung (South Korea)
2006
The strong acid triflimide ((CF3SO2)2NH) protonates chiral oxazaborolidines to form superactive, stable, Lewis acids which are highly effective catalysts for a wide variety of enantioselective Diels-Alder reactions, documented herein by more than 20 examples.
Tuberculosis (TB) is one of three major infectious diseases, and the control TB becoming more difficult because emergence multidrug-resistant extensively drug-resistant strains. In this study, we explored 1H NMR-based metabolomics using an aerobic infection model. Global profiling was applied to characterize responses C57Bl/6 mice with virulent Mycobacterium tuberculosis (MTB). The metabolic changes in organs (i.e., lung, target organ TB, spleen liver, remote systemic organs) serum from...
The cationic chiral Lewis acids 1 and 2, generated by triflic acid protonation of the corresponding neutral oxazaborolidines, serve as excellent catalysts for Diels-Alder addition cyclopentadiene to a wide variety dienophiles. Adducts have been obtained in yield enantioselectivity from alpha,beta-unsaturated esters, lactones, cyclic ketones. absolute facial selectivity each these substrates follows common pattern which differs that observed with alpha,beta-enals. different reaction channels...
The chiral oxazaborolidinium salt 1 (X = TfO) is an excellent catalyst for the cyanosilylation of methyl ketones promoted by trimethylsilyl cyanide and diphenylmethyl phosphine oxide as co-reactants (to generate Ph(2)MePOTMS(N=C:) a reactive intermediate). face selectivity this reaction parallels that previously observed corresponding aldehydes. A unifying rational mechanistic explanation provided these enantioselective reactions. Evidence presented to support importance alpha-C-H...O...
Stroke is one of the leading causes adult disability and death in developing countries. However, early diagnosis difficult no reliable biomarker currently available. Thus, we applied a 1H-NMR metabolomics approach to investigate altered metabolic pattern plasma urine from patients with cerebral infarctions sought identify biomarkers associated stroke.Metabolic profiles infarctions, especially small vessel occlusion, were investigated using spectroscopy coupled multivariate statistical...
The geographical origin of beef is increasing interest to consumers and producers due "mad cow" disease the implementation Free Trade Agreement (FTA). In this study, 1H NMR spectroscopy coupled with multivariate statistical analyses was used differentiate samples. Principal component analysis (PCA) orthogonal projection latent structure−discriminant (OPLS-DA) showed significant separation between extracts originating from four countries: Australia, Korea, New Zealand, United States. major...
Summary Background Asthma is a chronic inflammatory disease caused by complex interactions of genetic, epigenetic, and environmental factors. For this reason, new approaches are required to clarify the pathogenesis asthma systemic review. Objective We applied 1 H‐ NMR metabolomics approach investigate altered metabolic pattern in sera from patients with sought identify mechanism underlying potential biomarkers. Method A global profile ( n = 39) controls 26) was generated using spectroscopy...
A catalytic synthetic route to highly functionalized chiral cyclopropane derivatives was developed by Michael-initiated cyclopropanation of α-substituted acroleins with aryl- and alkyl diazoacetates. In the presence (S)-oxazaborolidinium cation 1b as a catalyst, reaction proceeded in high yield (up 93%) excellent diastereoselectivity 98% de) enantioselectivity 95% ee).
Abstract Non-alcoholic fatty liver disease (NAFLD) is one of the most frequent causes and its prevalence a serious growing clinical problem. Caloric restriction (CR) commonly recommended for improvement obesity-related diseases such as NAFLD. However, effects CR on hepatic metabolism remain unknown. We investigated metabolic dysfunction in obese diabetic db/db mice. found that mice reverted insulin resistance, steatosis, body weight adiposity to those db/m 1 H-NMR- UPLC-QTOF-MS-based...
The chiral oxazaborolidinium salts 1 and 2 are excellent catalysts for the enantioselective cyanosilylation of a wide variety aldehydes (see Table 1) using trimethylsilyl (TMS) cyanide triphenylphosphine oxide as source new reactive donor. This donor appears to be isocyanophosphorane Ph3P(OTMS)(NC:) (4). novel process described herein has several advantages: predictability absolute configuration cyanohydrin products from mechanistic model (3), high yields very good enantiomeric purity...
The chiral oxazaborolidinium cation 1 promotes Diels-Alder reactions between 2-triisopropylsilyloxy-1,3-butadiene and a number of unsymmetrical 1,4-benzoquinones in highly enantioselective structurally selective manner. basis for the enantioselectivity is explained rationally terms preferred type transition-state assembly. Selection rules have been developed that allow prediction principal reaction product diene quinone components.
New phenothiazine based organic dyes were prepared for visible-light-driven transformations. The 3,7-disubstituted derivatives showed visible light absorption and reversible one-electron oxidation behavior. In the presence of 0.5 mol % phenothiazines, primary benzylamines oxidative coupling under irradiation from a blue LED. electronic effect substituents in was observed catalytic activities. mechanistic pathway discussed on detection H2O2 after reaction.
An unprecedented high level of regioselectivities (up to 96%) in the intermolecular crossed acyloin condensations various aromatic aldehydes with acetaldehyde was realized by an appropriate choice N-heterocyclic carbene catalysts.
Curcuma, a genus of rhizomatous herbaceous species, has been used as spice, traditional medicine, and natural dye. In this study, the metabolite profile Curcuma extracts was determined using gas chromatography-time flight mass spectrometry (GC/TOF MS) ultrahigh-performance liquid chromatography–quadrupole time-of-flight (UPLC/Q-TOF to characterize differences between aromatica longa grown on Jeju-do or Jin-do islands, South Korea. Previous studies have performed primary profiling species in...
Breaking kamp: A catalytic route toward chiral α-alkyl-β-ketoesters using the title reaction of α-alkyl diazoester with aldehydes has been developed (see scheme). The proceeds high to excellent enantioselectivities and this methodology was applied a concise two-step synthesis natural pheromone sitophilate. Roskamp reaction,1 Lewis acid catalyzed alkyl diazoesters aldehydes, is powerful useful synthetic method construct β-keto carbonyl compounds, which have utilized in products2 (Scheme 1)....
This paper describes a catalytic enantioselective route to synthesize functionalized all-carbon quaternary acyclic systems via boron Lewis acid-promoted formal C-C insertion of diazoesters into aryl-CHO bonds. In the presence chiral (S)-oxazaborolidinium cation 1d as catalyst, reaction proceeded in good yield (up 83%) with regioselectivity 88:12) and excellent enantioselectivity 99% ee). The synthetic potential this method was illustrated by conversion products both α- β-amino esters.
Chiral Lewis acid catalyzed asymmetric formation of cyclobutanones from α-silyloxyacroleins and α-alkyl or α-aryl diazoesters has been developed. In the presence a chiral oxazaborolidinium ion catalyst, various α-silyloxycyclobutanones possessing β-quaternary center were synthesized in high yield (up to 91%) with excellent enantio- diastereoselectivity 98% ee up >20:1 dr) through tandem cyclopropanation/semipinacol rearrangement. The synthetic potential this method was illustrated by...
Abstract Obesity is a multifactorial health problem resulting from genetic, environmental and behavioral factors. A particularly interesting aspect of obesity the differences observed in response to same high-fat diet (HFD). In this study, we performed lipidomic profiling on livers HFD-fed C57BL/6J mice using ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. Mice were divided into three groups: normal (ND), HFD-obesity prone (HFD-OP) resistant (HFD-OR)....
A copper-catalyzed, enantioselective method for the borylallylation of vinyl arenes is reported. The reaction produces enantioenriched and functionalized organoboron compounds by sequentially incorporating boryl allyl groups onto C═C bond arenes. Copper-catalyzed borylative coupling with phosphates successfully proceeds in a regio- manner absence palladium cocatalyst.
ConspectusBoron Lewis acid catalysis has a long history and become one of the most powerful methods for organic synthesis. In addition to achiral boron catalysts such as BX3 (X = F, Cl, Br) B(C6F5)3, chiral are also significant synthetic tools used by chemists in academic laboratories industry. Since first reported Corey et al. 2002 (Corey J. Am. Chem. Soc. 2002, 124, 3808), oxazaborolidinium ion (COBI), an activated form proline-derived oxazaborolidine, been strong catalyst. Although early...
A catalytic route toward chiral Morita-Baylis-Hillman esters by asymmetric coupling between alpha,beta-acetylenic esters, aldehydes, and trimethylsilyl iodide has been developed (see scheme). The reaction proceeds with high to excellent enantioselectivities, the products can be transformed into beta-branched derivatives in a single step retention of configuration. TMS = trimethylsilyl.