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Structure of the allyl group. In organic chemistry, an allyl group is a substituent with the structural formula −CH 2 −HC=CH 2.It consists of a methylene bridge (−CH 2 −) attached to a vinyl group (−CH=CH 2).
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 ...
An alkyl carbanion is trigonal pyramidal. Vinyl anions are bent. 1,2-Disubstituted vinyl anions have E and Z isomers that undergo inversion through a linear transition state. However, delocalized carbanions may deviate from these geometries. Instead of residing in a hybrid orbital, the carbanionic lone pair may instead occupy a p orbital (or an ...
A phenyl group is the simplest aryl group, here bonded to an "R" group. In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. [1] "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the ...
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.
Alkyl boron compounds are in general stable, though easily oxidized. Boron often forms electron-deficient compounds without a full octet, such as the triorganoboranes. These compounds are strong electrophiles, but typically too sterically hindered to dimerize. Electron donation from vinyl and aryl groups can lend the C-B bond some double bond ...
Alkyl groups that contain one ring have the formula −C n H 2n−1, e.g. cyclopropyl and cyclohexyl. The formula of alkyl radicals are the same as alkyl groups, except the free valence "−" is replaced by the dot "•" and adding "radical" to the name of the alkyl group (e.g. methyl radical •CH 3).
Electrophilic additions to allyl- and vinylsilanes take advantage of this, and site selectivity generally reflects this property—electrophiles become bound to the carbon γ to the silyl group. The electron-donating strength of the carbon-silicon bond is similar to that of an acetamide substituent and equal to roughly two alkyl groups. [6]