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Updated: May 28, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Homoallylboration and homocrotylboration of aldehydes
1Department of Chemistry MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Abstract:
A simple method for addition of homoallylic fragments to aldehydes is described. Cyclopropanated allylboration reagents react with aldehydes in the presence of PhBCl(2) to give high yields of bishomoallyl alcohols. Cyclopropanated cis- and trans-crotyl reagents afford the corresponding 1,3-anti- and 1,3-syn-methyl-substituted "homocrotylated" alcohols with high selectivity, consistent with a Zimmerman-Traxler transition state. Accordingly, the optically active α-substituted reactant affords the E-substituted product in 97:3 er.
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