Intramolecular allylboration of γ-(ω-formylalkoxy)allylboronates for syntheses of trans- or cis-2-(ethenyl)tetrahydropyran-3-ol and 2-(ethenyl)oxepan-3-ol

• Yamamoto, Yasunori

• Kurihara, Kazunori

• Yamada, Akihiko

• Takahashi, Miki

• Takahashi, Youichi

• Miyaura, Norio

Abstract

3-Alkoxy-1-alkynes 4 were hydroborated with pinacolborane (HBpin) to give 3-alkoxy-1-alkenylboronates 5. The latter gave (E)-3-alkoxyallylboronates (8: (E)-(MeO)2CHCH2(CH2)nCH2OCH=CHCH2Bpin, n=1–3) when they were subjected to iridium-catalyzed isomerization of the double bond. The corresponding (Z)-isomers 10 were synthesized by nickel-catalyzed isomerization of 5. Both allylboronates underwent intramolecular allylboration leading to the formation of trans-2-(ethenyl)tetrahydropyran-3-ol or 2-(ethenyl)oxepan-3-ol from 8 and the corresponding cis-isomers from 10 in the presence of Yb(OTf)3 (20 mol%) in aqueous acetonitrile at 90°C.

Journal

• Tetrahedron

  Tetrahedron 59 (4), 537-542, 2003-01-20

  Elsevier Science Ltd.

Keywords

• allylboration
• pinacolborane
• iridium-catalyzed isomerization

Details

• CRID: 1050001338980276352
• NII Article ID: 120000957079
• HANDLE: 2115/15834
• ISSN: 00404020
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles