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Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH 3 CO) 2 O.Commonly abbreviated Ac 2 O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis.
This net reaction can also be described as follows: [PdCl 4] 2 − + C 2 H 4 + H 2 O → CH 3 CHO + Pd + 2 HCl + 2 Cl −. This conversion is followed by reactions that regenerate the Pd(II) catalyst: Pd + 2 CuCl 2 + 2 Cl − → [PdCl 4] 2− + 2 CuCl 2 CuCl + 1 / 2 O 2 + 2 HCl → 2 CuCl 2 + H 2 O. Only the alkene and oxygen are consumed.
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). [1] [2] When the acetylide is formed from acetylene (HC≡CH), the reaction gives an α-ethynyl alcohol. This process is often referred to as ethynylation.
Like phenols, aniline derivatives are highly susceptible to electrophilic substitution reactions. Its high reactivity reflects that it is an enamine, which enhances the electron-donating ability of the ring. For example, reaction of aniline with sulfuric acid at 180 °C produces sulfanilic acid, H 2 NC 6 H 4 SO 3 H.
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]
The displaced halide anion then usually reacts via another S N 2 reaction on one of the R 1 carbons, displacing the oxygen atom to give the desired phosphonate (4) and another alkyl halide (5). This has been supported by the observation that chiral R 1 groups experience inversion of configuration at the carbon center attacked by the halide anion.
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula C 2 H 4 or H 2 C=CH 2.It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. [7] It is the simplest alkene (a hydrocarbon with carbon–carbon double bonds).
Organolithium reagents can serve as nucleophiles and carry out S N 2 type reactions with alkyl or allylic halides. [46] Although they are considered more reactive than Grignard reagents in alkylation, their use is still limited due to competing side reactions such as radical reactions or metal–halogen exchange.