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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 ). [ 1 ] [ 2 ] The name is derived from the scientific name for garlic , Allium sativum .
Alkylation in biology causes DNA damage. It is the transfer of alkyl groups to the nitrogenous bases. It is caused by alkylating agents such as EMS (Ethyl Methyl Sulphonate). Bifunctional alkyl groups which have two alkyl groups in them cause cross linking in DNA.
Carbonyl allylation has been employed in the synthesis of polyketide natural products and other oxygenated molecules with a contiguous array of stereocenters. For example, allylstannanation of a threose-derived aldehyde affords the macrolide antascomicin B, which structurally resembles FK506 and rapamycin, and is a potent binder of FKBP12. [12]
In chemistry, an acyl group is a moiety derived by the removal of one or more hydroxyl groups from an oxoacid, [1] including inorganic acids. It contains a double-bonded oxygen atom and an organyl group (R−C=O) or hydrogen in the case of formyl group (H−C=O).
In organic chemistry, an alkyl group is an alkane missing one hydrogen. [1] The term alkyl is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of −C n H 2n+1. A cycloalkyl group is derived from a cycloalkane by removal of a hydrogen atom from a ring and has the general formula −C n H ...
A widely accepted mechanism involves a carbocation intermediate. The Fries rearrangement. In the first reaction step a Lewis acid for instance aluminium chloride AlCl 3 co-ordinates to the carbonyl oxygen atom of the acyl group. This oxygen atom is more electron rich than the phenolic oxygen atom and is the preferred Lewis base.
In chemistry, a carbonium ion is a cation that has a pentacoordinated carbon atom. [2] They are a type of carbocation. In older literature, the name "carbonium ion" was used for what is today called carbenium. Carbonium ions charge is delocalized in three-center, two-electron bonds. The more stable members are often bi- or polycyclic. [3]
According to the general principle, the Lewis acid first activates the electrophilic carbon in presence of allyltrimethylsilane which then undergoes nucleophilic attack from electrons on the allylic silane. [5] The silicon plays the key role in stabilizing the carbocation of carbon at the β-position.