Consecutive Application of the α-Alkynone Cyclization: Total Synthesis of (±)-Δ9(12)-Capnellene

✍ Scribed by Joan Huguet; Martin Karpf; André S. Dreiding

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: German
• Weight: 576 KB
• Volume: 65
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19820650806

✦ Synopsis

Abstract

The synthesis of the (±)‐form of the marine sesquiterpene (–)‐Δ^9(12)^‐capnellene (1) by double application of the a‐alkynone cyclization is described. Starting with 2, 2, 5‐trim ethylcyclopentanone (2), the elaboration of the tricyclo [6.3.0.0^2,6^]undecane C‐skeleton of 1 proceeded through the a‐alkynone 3, which was cyclized thermally to the bicyclo [3.3.0]octenone 4. For the anellation of the third five‐membered ring, 4 was transformed into the a‐alkynone 5 and the latter cyclized thermally to a mixture of the angular triquinenone 6 and the linear triquinenone 7. The last steps in the synthesis of (±)‐Δ^9(12)^‐capnellene (1) were then accomplished from 7 by known methods.