Synthesis of Substituted Cyclooctenones: Substituent Effects in the -Sigmatropic Rearrangement of Divinylcyclobutanols

Article abstract of DOI:10.1021/jo00245a017

From cyclobutanone 1 12 divinylcyclobutanols were prepared.Substituent effects on the rate of oxy-Cope rearrangement to form cyclooctenones were monitored by NMR.Divinylcyclobutanols 2a, 4a, 5a, 6a, and 8a gave first-order rate constants with the rates of rearrangements being in the order 4a < 5a < 2a < 6a < 3a < 8a.Cyclobutanols 7a, 9a, 10a, and 12a all rearranged too fast to isolate.The steric effects on the rate of rearrangement and the synthetic utility of this methodology are discussed.