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Updated: Jan 7, 2026

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Enantioselective Synthesis of a Key Intermediate toward Dragmacidin E via Base-Promoted Olefin
Noa Takahashi1, Shingo Harada1, Tetsuhiro Nemoto1
1Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Abstract:
We report a practical approach for synthesizing a chiral building block en route to the asymmetric total synthesis of dragmacidin E. The strategy features a base-promoted olefin isomerization of 1 followed by an Ir-catalyzed asymmetric hydrogenation under ambient hydrogen pressure. Gram-scale hydrogenation of geminally di-substituted olefin 5 using 3 mol% of the chiral Ir catalyst (R,R)-2 afforded (+)-(R)-3 in 88% yield and 89% enantiomeric excess (ee).
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