• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.327-333
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• 2009

For the Pt-catalyzed nucleophilic addition of enones, Pt complexes were employed in the presence of various phosphine ligands and $H_2\;(or\;Et_3SiH),$ affording inter- and intra-molecular coupling products in good to modest yield. Depending on reaction protocols, different phosphine ligands were required to optimize the conditions. In the aldol reaction, the Pt catalyst involving $P(2,4,6-(OMe)_3C_6H_2)3\;or\;P(p-OMeC_6H_4)_3$ was chosen. Michael reaction proceeds in good yields in the presence of $P(p-CF_3C_6H_4)_3$. Regarding the activity of the reductants, $H_2$ exhibited superior activity to $Et_3SiH$, resulting in a shorter reaction time and higher yield in the aldol and Michael reaction. In light of the deuterium labeling studies, the catalytic cycle including the hydrometalation of the enones by the platinum hydride species was proposed.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.252-259
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• 2013

A green and simple method to synthesize of 1,4-diketones via aldol reaction of arylglyoxals and ketones such as 1-(4-methoxyphenyl)-2-propanone, deoxybenzoin and substituted acetophenones in the presence of a catalytic amount of DABCO in water at room temperature has been reported. Corresponding 2-hydroxy-1,4-diones were obtained in moderate to high yields with simple separation of obtained solid from reaction mixture and recrystallization.

• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.107-110
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• 2015

Amino acid-catalyzed directed asymmetric aldol reactions showed enhanced enantioselectivity when conducted in ionic liquids. Optically active products were afforded in better yields (up to 23% higher) and enantiomeric excess (up to 21% higher) in ionic liquids than in conventional organic solvents.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.143-146
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• 2004

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.426-430
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• 1989

Amino alcohol-derived thiazolidinethiones [4-(S)-IPTT, 4(S)-ETT] serve as efficient chiral auxiliary in tin medicated aldol condensation. A highly enantioselective aldol-type reaction forming various ${\beta}$-hydroxy carbonyl compounds from 3-acetylthiazolidine-2-thione and achiral aldehyde is achieved via divalent tin enolate. The other advantages of these chiral auxiliaries were the ease of removal by methanolysis.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1590-1600
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• 2014

Cinchona-based bifunctional catalysts have been extensively employed in the field of organocatalysis due to the incorporation of both hydrogen-bonding acceptors (quinuclidine) and hydrogen-bonding donors (e.g., alcohol, amide, (thio)urea and squaramide) in the molecule, which can simultaneously activate nucleophiles and electrophiles, respectively. Among them, cinchona-derived (thio)urea and squaramide catalysts have shown remarkable application potential by using their bifurcated hydrogen bonding donors in activating electrophilic carbonyls and imines. However, due to their bifunctional nature, they tend to aggregate via inter- and intramolecular acid-base interactions under certain conditions, which can lead to a decrease in the enantioselectivity of the reaction. To overcome this self-aggregation problem of bifunctional organocatalysts, we have successfully developed a series of sulfonamide-based organocatalysts, which do not aggregate under conventional reaction conditions. Herein, we summarize the recent applications of our cinchona-derived sulfonamide organocatalysts in highly enantioselective methanolytic desymmetrization and decarboxylative aldol reactions. Immobilization of sulfonamide-based catalysts onto solid supports allowed for unprecedented practical applications in the synthesis of valuable bioactive synthons with excellent enantioselectivities.

• YAKHAK HOEJI
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• v.35 no.4
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• pp.335-340
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• 1991

The synthetic product of 1-hydroxymethyl-p-mentha-8-ene-2-one was afforded by the reaction between dihydrocarvone and formaldehyde. This reaction involves the aldol condensation. The preferential position of formaldehyde is methyl substituted .alpha.-carbon atom where these enols are regiospecifically formed. The hydroxymethylation of dihydrocarvone was also proved to happen regiospecifically in the position of .alpha.-methyl substituted ketone. When 1-hydroxymethyl-p-mentha-8-ene-2-one reacted with LiAIH$_{4}$, 1-hydroxymethyl-p-mentha-8-ene-2$\beta$-ol obtained. 1-Hydroxymethyl-p-mentha-8-ene-2-one reacted with PDC and chromic acid to give 1-formyl-p-mentha-8-ene-2-one and 1-carboxy-p-mentha-8-ene-2-one. When the hydroxymethyl group of 1-hydroxymethyl-p-menta-8-ene-2-one was reducted to methyl group, 1-methyl-p-menta-8-ene-2-one was obtained. Some of these new compound have certain odor. I, II have woody aroma and IV, V have camphory odors. IX has flowery minty odor.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.736-740
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• 2002

An efficient and practical synthetic method of △1 -3-octalone, which is a versatile building block for thesyntheses of polycyclic compounds, has been developed. The dianion of ethyl acetoacetate reacts with cyclohexene-1-carboxaldehyde (3) to produce the aldol adduct 6, which then undergoes Mn(Ⅲ)-mediated radical cyclization followed by acetate elimination to give △1 -3-octalone 4. A detailed mechanistic insight of Mn(Ⅲ)-mediated cyclization of 6 has been disclosed.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2563-2566
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• 2009

The first total synthesis of naturally occurring prorepensin with a bis-geranylated chalcone has been achieved by a convergent sequence. The key strategy involved in the synthesis of prorepensin was chalcone formation by aldol condensation of the corresponding geranylated acetophenone with geranylated benzaldehyde.

• Bulletin of the Korean Chemical Society
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• v.20 no.2
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• pp.217-219
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• 1999