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In organic chemistry, a vinyl group (abbr. Vi; [1] IUPAC name: ethenyl group [2]) is a functional group with the formula −CH=CH 2. It is the ethylene (IUPAC name: ethene) molecule ( H 2 C=CH 2 ) with one fewer hydrogen atom.
All feature three contiguous sp²-hybridized carbon centers and all derive stability from resonance. [6] Each species can be presented by two resonance structures with the charge or unpaired electron distributed at both 1,3 positions. Resonance structure of the allyl anion. The cation is identical, but carries an opposite-sign charge. [7]
Vinyl cations were first proposed in 1944 as a reactive intermediate for the acid-catalyzed hydrolysis of alkoxyacetylenes to give alkyl acetate. [5] In the first step of their facile hydration reaction, which was the rate limiting step, a vinyl cation reactive intermediate was proposed; the positive charge was believed to formally lie on a ...
β-Hydride elimination is a reaction in which a metal-alkyl centre is converted into the corresponding metal-hydride-alkene. [1] β-Hydride elimination can also occur for many alkoxide complexes as well. The main requirements are that the alkyl group possess a C-H bond β to the metal and that the metal be coordinatively unsaturated.
The migratory ability is ranked tertiary > secondary > aryl > primary. [7] Allylic groups are more apt to migrate than primary alkyl groups but less so than secondary alkyl groups. [5] Electron-withdrawing groups on the substituent decrease the rate of migration. [8] There are two explanations for this trend in migration ability. [9]
β-Carbon elimination (beta-carbon elimination) is a type of reaction in organometallic chemistry wherein an allyl ligand bonded to a metal center is broken into the corresponding metal-bonded alkyl (aryl) ligand and an alkene. [1] It is a subgroup of elimination reactions.
A solution of a carbonyl compound is added to a Grignard reagent. (See gallery) An example of a Grignard reaction (R 2 or R 3 could be hydrogen). The Grignard reaction (French:) is an organometallic chemical reaction in which, according to the classical definition, carbon alkyl, allyl, vinyl, or aryl magnesium halides (Grignard reagent) are added to the carbonyl groups of either an aldehyde or ...
The simplest aryl group is phenyl, which is made up of a benzene ring with one of its hydrogen atom replaced by some substituent, and has the molecular formula C 6 H 5 −. Note that a phenyl group is not the same as a benzyl group , the latter consisting of a phenyl group attached to a methyl group and a molecular formula of C 6 H 5 CH 2 − .