Related Experiment Video
Updated: Apr 29, 2026

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Unexpected E-stereoselective reductive A3-coupling reaction of terminal alkynes with aldehydes and amines
Wu Fan1, Weiming Yuan1, Shengming Ma2
1Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China.
Abstract:
The transition-metal catalysed three-component coupling of an alkyne, an aldehyde and an amine has been became a widely used method for preparing propargylic amines. Here, we report an unexpected copper(I)-catalysed E-stereoselective reduction of propargylic amines in situ formed from readily available terminal alkynes, aldehydes and 3-pyrroline or isoindoline via [1,5]-hydride transfer, affording E-allylic amines. Through mechanistic studies, it is believed that the unsaturated cyclic dialkylamine is acting as hydrogen donor.
Related Concept Videos
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
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.
Amines to Alkenes: Hofmann Elimination
Under thermal conditions, the hydroxide can abstract a proton from the β carbon; this generates an alkene with the simultaneous...
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia
When dissolved in liquid ammonia, an alkali metal, such...

