Search results
Results from the WOW.Com Content Network
In allyl compounds, where the next carbon is saturated but substituted once, allylic rearrangement and related reactions are observed. Allyl Grignard reagents (organomagnesiums) can attack with the vinyl end first. If next to an electron-withdrawing group, conjugate addition (Michael addition) can occur.
A site adjacent to the unsaturated carbon atom is called the allylic position or allylic site. A group attached at this site is sometimes described as allylic. Thus, CH 2 =CHCH 2 OH "has an allylic hydroxyl group". Allylic C−H bonds are about 15% weaker than the C−H bonds in ordinary sp 3 carbon centers and are thus more reactive.
Vinyl cation are invoked as reactive intermediates in solvolysis of vinyl halides, [1] [2] as well as electrophilic addition to alkynes and allenes. [3] Note that unlike the allyl and benzyl carbocations (top left and right, respectively), the electron-deficient carbon of the vinyl carbocation (bottom) is double-bonded.
Vinyl cation, a type of carbocation Vinyl group , a broad class of organic molecules in chemistry Vinyl polymer , a group of polymers derived from vinyl monomers
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]
In organic chemistry, vinylation is the process of attaching a vinyl group (CH 2 =CH−) to a substrate. Many organic compounds contain vinyl groups, so the process has attracted significant interest, especially since the reaction scope includes substituted vinyl groups. The reactions can be classified according to the source of the vinyl group.
Vinyl’s waterproof nature makes it easy to clean. For starters, you should vacuum regularly. For a deeper clean, you can mop it with water and mild detergent without worrying about damage.
The vinylogous enolate reacts at the terminal position of the double bond system (the γ-carbon), rather than the α-carbon immediately adjacent to the carbonyl, as would a simple enolate. Allylic electrophiles often react by vinylogous attack of a nucleophile rather than direct addition. Vinylogous aldol reaction. Cf. the simple aldol reaction.