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Updated: Feb 11, 2026

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Ring Expansion, Ring Contraction, and Annulation Reactions of Allylic Phosphonates under Oxidative Cleavage
Dupre Orr1, Nikolas Yousefi1, Thomas G Minehan1
1Department of Chemistry and Biochemistry , California State University , 18111 Nordhoff Street , Northridge , California 91330-8262 , United States.
Abstract:
Oxidative cleavage of cycloalkenylalkylphosphonates 1 followed by treatment with base gives rise to homologated cycloalkenones 2 in good to excellent yields. Subjecting cycloalk-2-enylphosphonates 3 to identical conditions provides the one-carbon ring-contracted compounds 4 in excellent yields. Oxidative cleavage of γ,δ-unsaturated ketophosphonates 6 followed by treatment with base affords 2-cyclopenten-1-ones 7 in good overall yields. This method may offer a practical alternative to existing methods for effecting one-carbon ring expansion, ring contraction, and annulation reactions.
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