• Title/Summary/Keyword: Diastereoselective

Search Result 40, Processing Time 0.023 seconds

Asymmetric Synthesis of (+)-trans-Aerangis Lactone

  • Kim, Aejin;Sharma, Satyasheel;Kwak, Jong Hwan;Kim, In Su
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.1
    • /
    • pp.75-78
    • /
    • 2013
  • Asymmetric synthesis of (+)-trans-aerangis lactone was achieved from commercially available 1-hexanol or 1-hexanal in four steps via iridium-catalyzed diastereoselective and enantioselective carbonyl crotylation from the alcohol or aldehyde oxidation level, and ruthenium-catalyzed olefin metathesis.

Stereocontrolled Dihydroxylation Reactions of Acyclic Allylic Amines (비고리 알릴아민 화합물의 입체선택적 이중알코올화 반응)

  • Jeon, Jongho;Shin, Nara;Kim, Young Gyu
    • Applied Chemistry for Engineering
    • /
    • v.25 no.5
    • /
    • pp.437-446
    • /
    • 2014
  • The dihydroxylation reaction of allylic amines is a facile and useful synthetic method to obtain amino diol structures that are widely found in lots of biologically important natural products. This review will focus on the recent methods of both substrate-controlled and ligand-controlled dihydroxylation reactions of acyclic allylic amines. In addition, several applications of the diastereoselective dihydroxylation methods to asymmetric syntheses of natural products are presented.

The diastereoselective synthesis of 2-methyl-5(S)-hexanolide (Carpenter bee pheromone의 2-methyl-5(S)-hexanolide의 부분 입체선택적 합성)

  • Chang, Jay-Hyok;Lee, Sang-Jun;Kim, Jung-Han
    • Applied Biological Chemistry
    • /
    • v.37 no.1
    • /
    • pp.25-29
    • /
    • 1994
  • 2-methyl-5(S)-hexanolide(1); the major component of pheromonal blend of the male carpenter bee was synthesized via Homer-Emmons reaction from Ethyl(S)-3-hydroxybutyrate(2a) which had been obtained by Baker's Yeast reduction in overall yield 39%.

  • PDF

Synthesis and Herbicidal Activity of New Hexahydrobenzisoxazole Derivatives (새로운 hexahydrobenzisoxazole derivatives 유도체의 합성 및 제초활성)

  • Kim, Hyoung-Rae;Park, Hyun-Ju;Kim, Hyung-Ki;Song, Jong-Hwan;Jeon, Dong-Ju;Kim, Kyung-Mahn;Kim, Tae-Joon;Ryu, Eung-K.
    • The Korean Journal of Pesticide Science
    • /
    • v.3 no.3
    • /
    • pp.68-70
    • /
    • 1999
  • Hexahydro-1,2-bertzisoxazol-4-ols prepared from the diastereoselective reductions of 3-aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones were reacted with benzyl chloride in the presence of sodium hydride to give new 4-benzyloxy-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazoles, which showed good herbicidal activity together with excellent selectivity on rice under submerged paddy conditions.

  • PDF

Highly Diastereoselective Aldol-Type Reaction Using 3-Acetylthiazolidine-2-thione (3-아세틸티아졸리딘-2-티온을 이용한 입체선택적인 알돌-축합반응)

  • Tae Myeong Jeong;Ki Hun Park
    • Journal of the Korean Chemical Society
    • /
    • v.33 no.4
    • /
    • pp.426-430
    • /
    • 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.

  • PDF

Diastereoselective Synthesis of Polysubstituted Pyrrolidinone as a Key Intermediate for the Anticancer Agents by Palladium(II)­Catalyzed Carboxylation

  • Choi Dong-Rack;Lee Kee-Young;Chung Yun-Sung;Joo Jae-Eun;Kim Yong-Hyun;Oh Chang-Young;Lee Yiu-Suk;Ham Won-Hun
    • Archives of Pharmacal Research
    • /
    • v.28 no.2
    • /
    • pp.151-158
    • /
    • 2005
  • Palladium(II)-catalyzed carboxylation of chiral olefins 6a-d has been examined under various conditions. In the weak basic condition ($K_{2}CO_3$), 7a-d were obtained in good yields. Alternatively, in the strong basic condition, pyrrolidinones 8a-d were obtained resulting in excellent yields and with high diastereoselectivity.

Diastereoselective Synthesis of Unsaturated 1,4-Amino Alcohols as a Biologically Important Moiety

  • Jung Young Hoon;Kim Ji Duck
    • Archives of Pharmacal Research
    • /
    • v.28 no.4
    • /
    • pp.382-390
    • /
    • 2005
  • chial allylic ethers with a hydroxyl group attached to the $\pi-system$ and chlorosulfonyl isocyanate. The enantioselectivity of the CSI reaction with the chiral allylic and benzylic ethers was examined in various solvents and temperatures. Based on these results, it was proposed that the CSI reaction is a competitive reaction of a $S_{N}i$ (retention) and a $S_{N}1$ mechanism (racemization) according to the stability of the carbocation intermediate. This means that there is a greater proportion of retention with the less stable the carbocation intermediate and vise versa.

NMR Signal Assignments of the Stereochemical Cycloadducts of Bicyclolactone via Diels-Alder Reaction

  • Kim, Dae-Sung;Seo, Chan-Woo;Cho, Cheon-Gyu;Won, Ho-Shik
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.8 no.1
    • /
    • pp.62-69
    • /
    • 2004
  • Bicyclolactones obtained from the Diels-Alder cycloaddition of 3,5-dibromo-2-pyrone can undergo various palladium catalyzed cross coupling reactions to afford aryl bicyclolactones. The resulting coupled products can be readily converted into various 3-OH cyclohexenes via lactone ring openings, while those bearing dienyl units underwent highly diastereoselective Diels-Alder cycloadditions with selected dienophiles to funish multiply functionalized polycarbocycles. Bromo-bicyclic diene furnished two different diastereomers endo-form (62%) and exo-form (38%) upon cycloadditions with N-Et maleimide (NEM), and their stereochemistries were identified with NMR.

  • PDF