• Title/Summary/Keyword: Phosphoranes

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Synthetic Studies Related to Antibiotics Containing Higher-carbon Sugars

  • Kim, Kwan-Soo
    • Korean Journal of Pharmacognosy
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    • v.16 no.4
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    • pp.239-242
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    • 1985
  • The anion of $6-benzenesulfonyl-3-O-benzyl-6-deoxy-1,2-O-isopropylidene-{\alpha}-d-glucofuranose$ was stable and reacted with carbon electrophiles to give higher-carbon sugars. Reactions of uridine 5'-aldehyde with phosphoranes afforded heptofuranose nucleosides.

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Reaction of Phosphorus Ylides with Carbonyl Compounds in Supercritical Carbon Dioxide (초임계 이산화탄소에서의 유기인 일리드와 카르보닐 화합물의 반응)

  • Jeong, Kyung-Il;Kim, Hak-Do;Shim, Jae-Jin;Ra, Choon-Sup
    • Journal of the Korean Chemical Society
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    • v.48 no.1
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    • pp.28-32
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    • 2004
  • The condensation reaction of (benzylene)triphenylphosphoranes with carbonyl compounds in supercritical carbon dioxide was examined. Reactions of (benzylene)phosphoranes (ca. 1 mmol) with several benzaldehydes in a supercritical carbon dioxide (80 $^{\circ}C$, 2,000 psi) containing THF entrainer (5%) in a 24 mL reactor proceed smoothly to yield olefination products in fairly good to excellant yields but slower, compared to reactions in a conventional THF solvent. Generally, phosphoranes that are not substituted with a nitro group show more (Z)-selective reactions with aromatic aldehydes under $scCO_2$ condition than in THF. The reaction of (benzylene)triphenylphosphoranes with 4-t-butylcyclohexanone gave the corresponding olefin compounds with a low conversion under both the supercritical carbon dioxide and the organic THF solvent. Our preliminary study showed the Wittig reaction carries out smoothly in supercritical carbon dioxide medium and also a possibile tunability of this reaction pathway by adding a entrainer. The results would be useful for devising a novel process for the environmentally friendly Wittig reaction.