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Updated: Jun 6, 2025

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Brønsted Acid-Catalyzed, Asymmetric Allenoate Claisen Reaction
Rachael E Hamilton1, Ellen A Berkley1, Iain K Laufer1
1Keck Science Department, Scripps, Claremont McKenna, and Pitzer Colleges, Claremont, California 91711, United States.
Abstract:
An auxiliary-based protocol is described for an asymmetric allenoate Claisen rearrangement. Silicated tosic acid (10 mol %) was used as an inexpensive, user-friendly catalyst. Stereochemical analysis revealed a preferential attack at the si face of prostereogenic olefin. The amine auxiliary was readily hydrolyzed and can be isolated from the reaction mixture (85-87% recovery). The resulting unsaturated β-keto esters were isolated in ≤99% yield and 98% ee. Diastereoselective examples provided a 96:4 syn:anti ratio of the resulting vicinal stereocenters.
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