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Updated: Jun 29, 2025
Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Accessing Z-Enynes via Cobalt-Catalyzed Propargylic Dehydrogenation
Alexandra K Bodnar1, Timothy R Newhouse1
1Department of Chemistry, Yale University, 225 Prospect St, New Haven, Connecticut, 06520-8107, United States.
Abstract:
Alkenes constitute an enabling motif in organic synthesis, as they can be functionalized to form highly substituted molecules. Z-alkenes are generally challenging to access due to the thermodynamic preference for the formation of E-alkenes compared to Z-alkenes. Dehydrogenation methodologies to selectively form Z-alkenes have not yet been reported. Herein, we report a Z-selective, propargylic dehydrogenation that provides 1,3-enynes through the invention of a Co-catalyzed oxidation system. Observation of a kinetic isotope effect (KIE) revealed that deprotonation of the propargylic position is the rate limiting step. Additionally, isomerization experiments were conducted and confirmed that the observed Z-selectivity is a kinetic effect. A proposed stereomechanistic model for the Z-selectivity is included.
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