Limanto J,
Snapper ML.
*
Boston College, Chestnut Hill, USA
Sequential Intramolecular Cyclobutadiene Cycloaddition, Ring-Opening Metathesis, and Cope Rearrangement: Total Syntheses of (+)- and (–)-Asteriscanolide.
J. Am. Chem. Soc. 2000;
122: 8071-8072
DOI:
10.1021/ja001946b
Key words
(+)-asteriscanolide - sesquiterpene - electrocyclization - cycloaddition - Cope rearrangement - cyclobutadiene
Significance
Snapper and Limanto present a concise synthesis of the sesquiterpene (+)-asteriscanolide. The authors use a combination of different pericyclic reactions to assemble the eight-membered ring of the natural product in an elegant fashion. Their work showcases the use of iron-complexed cyclobutadienes in total synthesis.
Comment
A photochemical electrocyclization of α-pyrone A followed by CO2 elimination furnished iron-complexed cyclobutadiene B. Further functionalization gave access to cycloaddition precursor G. Cyclobutadiene cycloaddition, followed by ring-opening metathesis and Cope rearrangement quickly assembled cyclooctadiene J which was converted into (+)-asteriscanolide in four steps.
