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In organic chemistry, alkynylation is an addition reaction in which a terminal alkyne (−C≡CH) is added to a carbonyl group (C=O) to form an α-alkynyl alcohol (R 2 C(−OH)−C≡C−R).
The first example of catalytic asymmetric addition of alkynylzinc compounds to aldehydes was reported by KensÅ Soai and co-workers in 1990. In their experiments, chiral amino alcohols (A and B in the figure) and amines (such as C) were used as ligands, and the alkynylzinc reagent was prepared from reaction of alkyne with diethylzinc .
Typical route for alkylation of benzene with ethylene and ZSM-5 as a heterogeneous catalyst. Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents).
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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 alkynylation reaction of aryl halides using aromatic acetylenes was reported in 1975 in three independent contributions by Cassar, [4] Dieck and Heck [5] as well as Sonogashira, Tohda and Hagihara. [6] All of the reactions employ palladium catalysts to afford the same reaction products.
The alkyne zipper reaction requires a strong base, which can be generated from the reaction of potassium hydride and a diamine: [3] [1] Alkyne zipper reaction. The potassium 3-aminopropylamide deprotonates the less-substituted methylene adjacent to the alkyne group. [3] [1] Example mechanism for alkyne zipper reaction.
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