- Chiral oxazaborolidinone-mediated enantioselective ring-cleavage reaction of a mixture of diastereomeric 1,3-dioxolane acetals: Application to asymmetric desymmetrization of meso-1,2-diols
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Ring-cleavage reaction of a mixture of diastereomeric dioxolane acetals syn- and anti-1b-e proceeds in an enantiodifferentiating manner in the presence of chiral Lewis acid 2. The reaction is utilized as a key step in asymmetric desymmetrization of meso-1,2-diols.
- Harada,Yamanaka,Oku
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- Asymmetric desymmetrization of saturated and unsaturated meso-1,2-diols
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An asymmetric desymmetrization of saturated and unsaturated cyclic and acyclic meso-1,2-diols has been developed from the ene acetals, prepared from the norbornene carboxyaldehyde and meso-1,2-diols. The intramolecular haloetherification of the ene acetals as a key step afforded 8-membered acetals in a stereoselective manner just by the reaction of norbornene olefin even when the ene acetals from unsaturated meso-1,2-diols having olefins in the same molecule were used. Subsequent reductive elimination, followed by protecting the hydroxy group and transacetalization, gave optically active 1,2-diol derivatives and the starting ene acetals in good yields. (C) 2000 Elsevier Science Ltd.
- Fujioka, Hiromichi,Nagatomi, Yasushi,Kotoku, Naoyuki,Kitagawa, Hidetoshi,Kita, Yasuyuki
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p. 10141 - 10151
(2007/10/03)
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- SYNTHESES OF ALL FOUR POSSIBLE DIASTEREOMERS OF THE ACYCLONUCLEOSIDE 9-(1,3,4-TRIHYDROXY-2-BUTOXYMETHYL)GUANINE FROM CARBOHYDRATE PRECURSORS
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The syntheses of all four possible diastereomers of 9-(1,3,4-trihydroxy-2-butoxymethyl)guanine, starting from D- and L-xylose and from D- and L-arabinose derivatives are described.
- MacCoss, Malcolm,Chen, Anna,Tolman, Richard L.
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p. 4287 - 4290
(2007/10/02)
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