An anionic C(3)-C(5) ring expansion of beta-ketocyclopropanes to cyclopentenols.
[reaction: see text] When treated with base, beta-ketocyclopropylcarboxylates ring-open to initially afford either cis or trans alpha,beta-unsaturated ketones. The cis isomer undergoes an intramolecular aldol reaction to afford allylic cyclopentenols in high yield and excellent diastereoselectivity. Choice of base is key to a successful outcome.
Greatrex
Ben W
BW
Department of Chemistry, University of Adelaide, South Australia, Australia, 5005.
Taylor
Dennis K
DK
Tiekink
Edward R T
ER