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Phenylacetylene is a prototypical terminal acetylene, undergoing many reactions expected of that functional group. It undergoes semi hydrogenation over Lindlar catalyst to give styrene . In the presence of base and copper(II) salts, it undergoes oxidative coupling to give diphenylbutadiyne . [ 6 ]
Yet another method involves the coupling of iodobenzene and the copper salt of phenylacetylene in the Castro-Stephens coupling. The related Sonogashira coupling involves the coupling of iodobenzene and phenylacetylene. Diphenylacetylene is a planar molecule. The central C≡C distance is 119.8 picometers. [1]
Free-radical reactions depend on one or more relatively weak bonds in a reagent. Under reaction conditions (typically heat or light), some weak bonds homolyse into radicals, which then induce further decomposition in their compatriots before recombination. Different mechanisms typically apply to reagents without such a weak bond.
An ICE table or RICE box or RICE chart is a tabular system of keeping track of changing concentrations in an equilibrium reaction. ICE stands for initial, change, equilibrium . It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. [ 1 ]
The Hay coupling is variant of the Glaser coupling. It relies on the TMEDA complex of copper(I) chloride to activate the terminal alkyne. Oxygen (air) is used in the Hay variant to oxidize catalytic amounts of Cu(I) to Cu(II) throughout the reaction, as opposed to a stoichiometric amount of Cu(II) used in the Eglington variant. [7]
Trimethylsilylacetylene is commercially available. It may also be prepared in a manner similar to other silyl compounds: deprotonation of acetylene with a Grignard reagent, followed by reaction with trimethylsilyl chloride. [4] Trimethylsilylacetylene is a precursor to 1,4-bis(trimethylsilyl)buta-1,3-diyne, a protected form of 1,3-butadiyne. [5]
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These reactions invariably involve metal-acetylide intermediates. This reaction was discovered by chemist John Ulric Nef in 1899 while experimenting with reactions of elemental sodium, phenylacetylene, and acetophenone. [3] [4] For this reason, the reaction is sometimes referred to as Nef synthesis.