• Title/Summary/Keyword: Diastereoselective

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Introduction of a New Chiral Oxazolidin-2-one Derived from D-Mannitol and Its Applications as a Chiral Auxiliary

  • Kim, Si-Min;Jin, Hyun-Yong;Jun, Jong-Gab
    • Bulletin of the Korean Chemical Society
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    • v.23 no.5
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    • pp.749-757
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    • 2002

  • Chiral oxazolidin-2-one is easily prepared from D-mannitol and demonstrated to undergo highly diastereoselective alkylation reactions via lithium imide Z-enolates of its N-acyl derivatives to afford ${\alpha}-branched$ products. Evans syn and non-Evans sy n aldol products were also selectively obtained using this new auxiliary in high diastereomeric purity by simply changing the stoichiometry of TiCl4 and the nature of the amine base. Also, this new auxiliary is employed in diastereoselective Staudinger-type ${\beta}-lactam$ syntheses. Using 2-chloro-1-methylpyridinium iodide as the dehydrating agent, the reaction of auxiliary tethered acetic acid with trans imines gave the desired ${\beta}-lactams$ with cis-selectivity.

  • https://doi.org/10.5012/bkcs.2002.23.5.749 인용 PDF KSCI

Regio- and Diastereoselective 1,3-Dipolar Cycloaddition between Perfluoro-2-methyl-2-pentene and Nitrones: A Facile Approach to Partially-Fluorinated Isoxazolidines

  • Moon, Mi-Eun;Park, Joo-Yeon;Jeong, Eun-Ha;Vajpayee, Vaishali;Kim, Hyun-Uk;Chi, Ki-Whan
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1515-1518
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    • 2010

  • Regio- and diastereoselective 1,3-dipolar cycloaddition reactions of nitrones {(Z)-${\alpha}$-phenyl-N-methylnitrone (1a) and (Z)-${\alpha}$-propyl-N-butylnitrone (1b)} with electron-deficient perfluoro-2-methyl-2-pentene (2) lead to novel isoxazolidines {5-fluoro-5-pentafluoroethyl-4,4-bis-trifluoromethyl-2-methyl-3-phenyl-isoxazolidine (3a) and 2-butyl-5-fluoro-5-pentafluoroethyl-4,4-bis-trifluoromethyl-3-propyl-isoxazolidines (3b) respectively} as major constituents. These derivatives were characterized by IR, $^1H$ and $^{19}F$ NMR, GC-MS and NOE measurements, and the absolute structure of 3a was confirmed by X-ray crystallography.

  • https://doi.org/10.5012/bkcs.2010.31.6.1515 인용 PDF KSCI

Diastereoselective Synthesis of anti-1,2-Aminoalcohol by Palladium(II) Catalyzed Aza-Claisen Rearrangement

  • Yoon, Youn-Jung;Chan, Myung-Hee;Joo, Jae-Eun;Kim, Yong-Hyun;Oh, Chang-Young;Lee, Kee-Young;Lee, Yiu-Suk;Ham, Won-Hun
    • Archives of Pharmacal Research
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    • v.27 no.2
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    • pp.136-142
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    • 2004

  • In this study, a highly diastereoselective synthesis of anti-1 ,2-aminoalcohol was explored starting from L-amino acids as chiral sources. The higher yield and diastereoselectivity was shown when the aza-Claisen rearranqement was performed with allylic trichloroacetimidate 6a in the presence of palldium(II) catalyst.

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