Wender PA,
*,
Ihle NC,
Correia CR. D.
Stanford University, USA
Nickel-Catalyzed Intramolecular [4+4] Cycloadditions. 4. Enantioselective Total Synthesis
of (+)-Asteriscanolide.
J. Am. Chem. Soc. 1988;
110: 5904-5906
DOI:
10.1021/ja00225a055
Key words
(+)-asteriscanolide - [4+4] cycloaddition - Brinkmeyer reduction - Claisen rearrangement
- cyclooctadiene synthesis - hydroalumination - Swern oxidation
Significance
Wender and co-workers report the first total synthesis of sesquiterpinoid lactone
(+)‑asteriscanolide. Key to their approach is a nickel-catalyzed [4+4]-cycloaddition
methodology, which was developed in their group. They successfully establish the first
asymmetric synthesis of a cyclooctane-containing terpenoid.
Comment
The synthesis commences with construction of acid F through a Claisen rearrangement. Asymmetric Brinkmeyer reduction of ketone H with LAH in presence of Darvon alcohol (I) as a chiral ligand gives rise to J with excellent enantioselectivity. Tetraene M was accessed by a hydroalumination stannylation sequence followed by lithiation and
carboxylation. The key nickel-catalyzed intramolecular [4+4] cycloaddition forged
cyclooctadiene N.
