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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.
This scenario occurs when the allylic substituent at the 1 position is a hydrogen bond donor (usually a hydroxyl) and the substituent at the 3 position is a hydrogen bond acceptor (usually an ether). Even in cases where the allylic system could conform to put a much smaller hydrogen in the hydrogen bond acceptor’s position, it is much more ...
For cyclic allylic alcohols, greater selectivity is seen when the alcohol is locked in the pseudo equatorial position rather than the pseudo axial position. [2] However, it was found that for metal catalyzed systems such as those based on vanadium, reaction rates were accelerated when the hydroxyl group was in the axial position by a factor of 34.
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).
Allyl alcohol is converted mainly to glycidol, which is a chemical intermediate in the synthesis of glycerol, glycidyl ethers, esters, and amines. Also, a variety of polymerizable esters are prepared from allyl alcohol, e.g. diallyl phthalate. [5] Allyl alcohol has herbicidal activity and can be used as a weed eradicant [9]) and fungicide. [8]
A significant issue associated with the reduction of allylic sulfones is transposition of the allylic double bond, which occurs in varying amounts during reductions by metal amalgams. [ 14 ] and tin hydrides [ 15 ] Palladium-catalyzed reductive desulfonylations of allylic sulfones do not have this issue, and afford allylic sulfones with high ...
The red and white balls represent the hydroxyl group (−OH). The three "R"s stand for carbon substituents or hydrogen atoms. [1] In chemistry, an alcohol (from Arabic al-kuḥl 'the kohl'), [2] is a type of organic compound that carries at least one hydroxyl (−OH) functional group bound to a saturated carbon atom.
With the use of these reagents, allylic alcohols and isolated olefins can be selectively cyclopropanated in the presence of each other. Iodo- or chloro- methylsamarium iodide in THF is an excellent reagent to selectively cyclopropanate the allylic alcohol, presumably directed by chelation to the hydroxyl group. [35]