Related Experiment Video
Updated: May 18, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Zirconium catalyzed alkyne dimerization for selective Z-enyne synthesis
Rachel H Platel1, Laurel L Schafer
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
Abstract:
The regioselective head-to-head dimerization of alkynes is catalyzed by a dibenzyl tethered bis(ureate) zirconium precatalyst with aniline as an additive. This system also gives outstanding stereoselectivity to furnish Z-enynes in high yields. A dinuclear reactive intermediate has been characterized, which provides a potential mechanistic rationale for the unexpected regio- and stereoselectivity in this catalytic system.
More Related Videos
Related Concept Videos
Preparation of Alkynes: Alkylation Reaction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Preparation of Alkynes: Dehydrohalogenation
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
Electrophilic Addition to Alkynes: Hydrohalogenation

