Stereocontrolled total synthesis of polygalolide A

Hitomi Yamada, Masaatsu Adachi, Minoru Isobe, Toshio Nishikawa

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The total synthesis of polygalolide A, a secondary metabolite that was isolated from a Chinese medicinal plant, is reported. A key issue in this synthesis was construction of an oxabicyclo[3.2.1] skeleton, which was solved by the development of an intramolecular Ferrier-type C-glycosylation of a glucal with siloxyfuran as an internal nucleophile. The substrate was prepared from D-glucal by the introduction of trimethylsilylacetylene and siloxyfuran groups. Although C-glycosylation did not occur under the conditions found from model experiments, further examination revealed that the combination of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and 2,4,6-collidine successfully afforded the desired product as a single diastereomer. The siloxy group at the C3 position played a crucial role in the stereocontrol of this reaction. The product was further transformed into a tetracyclic compound as follows: The vinyl ether and acetylenic moieties were reduced and the siloxy group was removed with a Barton-McCombie reaction. The construction of the six-membered ether and the γ-lactone provided the tetracyclic compound. Finally, a phenolic moiety was introduced by using a Mukaiyama aldol reaction to furnish polygalolide A.

Original languageEnglish
Pages (from-to)1428-1435
Number of pages8
JournalChemistry - An Asian Journal
Volume8
Issue number7
DOIs
Publication statusPublished - 2013 Jul 1
Externally publishedYes

Keywords

  • glycosylation
  • heterocycles
  • natural products
  • polygalolides
  • total synthesis

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry

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