• Title/Summary/Keyword: Chiral catalyst

Search Result 52, Processing Time 0.03 seconds

Regulation of Stereoselectivity and Reactivity in the Inter- and Intramolecular Allylic Transfer Reactions

  • Yu, Chan-Mo;Youn, Jin-soup;Jung, Hee-Keum
    • Bulletin of the Korean Chemical Society
    • /
    • v.27 no.4
    • /
    • pp.463-472
    • /
    • 2006
  • The preparation of enatiomerically enriched homoallylic alcohols through asymmetric addition of chiral allylic transfer reagents and allylating reagents with chiral catalysts to the carbonyl functionalities represents an important chemical transformation. Excellent progress has been made over past decade in the development and application of catalytic asymmetric allylic transfer reactions. In this account, our efforts for the various intermolecular allylic transfer reactions such as allylation, propargylation, allenylation, and dienylation utilizing accelerating strategy and sequential allylic transfer reactions to achieve multiple stereoselection mainly using transition metal catalysts are described.

Intramolecualr cyclization of a dipyrromethane by an electrophilic aromatic substitution reaction producing a new chiral compound

  • Kim, Seung Hyun;Kim, Sung Kuk
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.22 no.4
    • /
    • pp.115-118
    • /
    • 2018
  • Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.

Highly Enantioselective Rh-catalyzed Transfer Hydrogenation of α-Functionalized Arylketones

  • Lee, Do-Min;Kwak, Se-Hun;Lee, Kee-In
    • Bulletin of the Korean Chemical Society
    • /
    • v.30 no.6
    • /
    • pp.1317-1324
    • /
    • 2009
  • Asymmetric transfer hydrogenation of α-functionalized arylketones has been studied. The chiral Rh-catalyst effectively performed in transfer hydrogenation of $\alpha$-mesyloxyketones with an azeotropic mixture of formic acid/triethylamine to produce optically active 1-arylethandiols with excellent enantioselectivity.

Solvent-free Microwave-Assisted Ortho-Alkylation of Aromatic Ketimine with Acrylic Acid Derivatives by Rh(I) Catalyst

  • Jo, Eun-Ae;Ahn, Jeong-Ae;Jun, Chul-Ho
    • Bulletin of the Korean Chemical Society
    • /
    • v.28 no.11
    • /
    • pp.2020-2024
    • /
    • 2007
  • The article reports the synthesis of a novel bispyridino-18-crown-6 ether, 7-{[(5S,15S)-5,15-diphenyl- 3,6,14,17-tetraoxa-23,24-diazatricyclo[17.3.1.18,12]tetracosa-1(23),8(24),9,11,19,21-hexaen-10-yl]oxy}heptylferrocenamide 6, bearing the C2-symmetric diphenyl substituents as chiral barriers and the ferrocenyl groups serving as an electrochemical sensor, and its electrochemical study with D- and L-AlaOMe·HCl as the guest by cyclovoltametry.

Effect of Alumina Nanooxide Application on Nitrendipine Manufacturing Process (알루미나 나노산화물이 Nitrendipine 제조 공정에 미치는 영향)

  • Chae, E.J.;Uhm, Y.R.;Han, B.S.;Rhee, C.K.;Park, S.E.
    • Journal of Powder Materials
    • /
    • v.14 no.2 s.61
    • /
    • pp.127-131
    • /
    • 2007
  • The alumina nano powders synthesized by levitational gas condensation (LGC) method were applied to catalyst in manufacturing process of Hanzsch reaction for Nitrendipine. The L-tartaric acid on the surface is carried out with participation of carbonyl fragments, O-H, C-H bonds which affects stereo selectivity, yield on the reagents positively. From the analysis of the IR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. From the analysis of the rR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. The newly created bonds made a chiral center on the final product.