Synthesis of 5-Hydroxycyclopent-2-enones from Allenyl Vinyl Ketones via an Interrupted Nazarov Cyclization
Vanessa M. Marx and D. Jean Burnell*
*Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3, Email: jean.burnelldal.ca
V. M. Marx, D. J. Burnell, Org. Lett., 2009, 11, 1229-1231.
Treatment of an allenyl vinyl ketone with trifluoroacetic acid leads to Nazarov cyclization, in which the intermediate carbocation is trapped efficiently by trifluoroacetate. Hydrolysis of the ester with methanol and basic alumina provides a trans-disubstituted 5-hydroxycyclopent-2-enone in very good yields.
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Nazarov Cyclization, Cyclopentenones