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Consecutive Application of the α‐Alkynone Cyclization: Total Synthesis of (±)‐Δ 9(12) ‐Capnellene
Author(s) -
Huguet Joan,
Karpf Martin,
Dreiding André S.
Publication year - 1982
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19820650806
Subject(s) - undecane , chemistry , sesquiterpene , bicyclic molecule , ring (chemistry) , stereochemistry , skeleton (computer programming) , elaboration , trim , organic chemistry , humanities , philosophy , computer science , programming language , operating system
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.