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Updated: Jul 17, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Phosphine-catalyzed cycloadditions of allenic ketones: new substrates for nucleophilic catalysis
Debra J Wallace1, Rachel L Sidda, Robert A Reamer
1Department of Process Research, Merck Sharp and Dohme Research Laboratories, Hertford Road, Hoddesdon, Herts, EN11 9BU, UK. debra_wallace@merck.com
Abstract:
A range of phosphine-catalyzed cycloaddition reactions of allenic ketones have been studied, extending the scope of these processes from the more widely used 2,3-butadienoates to allow access to a number of synthetically useful products. Reaction of allenyl methyl ketone 4 with exo-enones afforded spirocyclic compounds in good regioselectivity and promising enantioselectivity via a [2 + 3] cycloaddtion. Aromatic allenyl ketones undergo a phosphine-promoted dimerization to afford functionalized pyrans, leading to a formal [2 + 4] Diels-Alder product, but did not react in the [2 + 3] cycloaddition. The results from other reactions that had found utility with 2,3-butadienoates are also reported.
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