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Several modifications of alkynylation reactions are known: In the Arens–van Dorp synthesis the compound ethoxyacetylene [7] is converted to a Grignard reagent and reacted with a ketone, the reaction product is a propargyl alcohol.
This alkynylation reaction is enantioselective and involves an alkynylzinc reagent [1] rather than the sodium acetylide used by John Ulric Nef in his 1899 report of the synthetic approach. [ 2 ] [ 3 ] Propargyl alcohols are versatile precursors for the chirally-selective synthesis of natural products and pharmaceutical agents , making this ...
The Seyferth–Gilbert homologation is a chemical reaction of an aryl ketone 1 (or aldehyde) with dimethyl (diazomethyl)phosphonate 2 and potassium tert-butoxide to give substituted alkynes 3. [ 1 ] [ 2 ] Dimethyl (diazomethyl)phosphonate 2 is often called the Seyferth–Gilbert reagent .
English: Diagram showing the chemical reaction involving Sonogashira reaction of a phenylalanine derivative with an alkyne. Modified from File:Alkynylation.gif to correct chemical errors. Date
The Corey–Fuchs reaction, also known as the Ramirez–Corey–Fuchs reaction, is a series of chemical reactions designed to transform an aldehyde into an alkyne. [1] [2] [3] The formation of the 1,1-dibromoolefins via phosphine-dibromomethylenes was originally discovered by Desai, McKelvie and Ramirez. [4]
A 3D model of ethyne (), the simplest alkyneIn organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. [1] The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula C n H 2n−2.
The reaction medium must be basic to neutralize the hydrogen halide produced as the byproduct of this coupling reaction, so alkylamine compounds such as triethylamine and diethylamine are sometimes used as solvents, but also DMF or ether can be used as solvent. Other bases such as potassium carbonate or cesium carbonate are occasionally used.
The reaction proceeds through generation of an acylium center. The reaction is completed by deprotonation of the arenium ion by AlCl 4 −, regenerating the AlCl 3 catalyst. However, in contrast to the truly catalytic alkylation reaction, the formed ketone is a moderate Lewis base, which forms a complex with the strong Lewis acid aluminum ...