Related Experiment Video
Updated: Mar 7, 2026

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Unsymmetrical E-Alkenes from the Stereoselective Reductive Coupling of Two Aldehydes
Keyhan Esfandiarfard1, Juri Mai1, Sascha Ott1
1Department of Chemistry, Ångström Laboratory, Uppsala University , Box 523, 75120 Uppsala, Sweden.
Abstract:
The unprecedented formation of unsymmetrical alkenes from the intermolecular reductive coupling of two different aldehydes is described. In contrast to the McMurry reaction which affords statistical product mixtures, selectivity in the reported procedure is achieved by a sequential ionic mechanism in which a first aldehyde is reacted with a phosphanylphosphonate to afford a phosphaalkene intermediate which, upon activation by hydroxide, reacts with a second aldehyde to the unsymmetrical E-alkenes. The described reaction is free of transition metals and proceeds under ambient temperature within minutes in good to excellent overall yields. It is a new methodology to use feedstock aldehydes for the direct production of C═C double bond-containing products and may impact how chemists think of multistep synthetic sequences in the future.
Related Concept Videos
E2 Reaction: Stereochemistry and Regiochemistry
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major...
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
E1 Reaction: Stereochemistry and Regiochemistry

