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.
In contrast, the sp 2-hybridized carbon atoms resonate around 80 ppm in a region typical for alkyne and nitrile carbon atoms, while the protons of a CH 2 group of a terminal allene resonate at around 4.5 ppm — somewhat upfield of a typical vinylic proton.
The vinyl cation is a carbocation with the positive charge on an alkene carbon. Its empirical formula of the parent ion is C 2 H + 3.Vinyl cation are invoked as reactive intermediates in solvolysis of vinyl halides, [1] [2] as well as electrophilic addition to alkynes and allenes.
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.
α,β-Unsaturated carbonyl compounds featuring a carbonyl conjugated to an alkene that is terminal, or vinylic, contain the acryloyl group (H 2 C=CH−C(=O)−); it is the acyl group derived from acrylic acid. The preferred IUPAC name for the group is prop-2-enoyl, and it is also known as acrylyl or simply (and incorrectly) as acryl. Compounds ...
In the initiation phase, a pro-oxidant hydroxyl radical (OH•) abstracts the hydrogen at the allylic position (–CH 2 –CH=CH 2) or methine bridge (=CH−) [clarification needed] on the stable lipid substrate, typically a polyunsaturated fatty acid (PUFA), to form the lipid radical (L•) and water (H 2 O).
At room temperature, acetaldehyde (H 3 CC(O)H) is more stable than vinyl alcohol (H 2 C=CHOH) by 42.7 kJ/mol. [3] Vinyl alcohol gas isomerizes to the aldehyde with a half-life of 30 min at room temperature.