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An illustrative example is the epoxidation of trans-2-butene with m-CPBA to give trans-2,3-epoxybutane: [4] The oxygen atom that adds across the double bond of the alkene is taken from the peroxy acid, generating a molecule of the corresponding carboxylic acid as a byproduct.
meta-Chloroperoxybenzoic acid (mCPBA or mCPBA) is a peroxycarboxylic acid. It is a white solid often used widely as an oxidant in organic synthesis. mCPBA is often preferred to other peroxy acids because of its relative ease of handling. [1] mCPBA is a strong oxidizing agent that may cause fire upon contact with flammable material. [2]
The most common use of organic peroxy acids is for the conversion of alkenes to epoxides, the Prilezhaev reaction. Formation of an epoxide from an alkene and a peroxycarboxylic acid. Another common reaction is conversion of cyclic ketones to the ring-expanded esters using peracids in a Baeyer-Villiger oxidation .
Alkenes bound to both electron-withdrawing and -donating groups tend to behave like the former, requiring long oxidation times and occasionally some heating. Like electron-poor epoxides, epoxide products from this class of substrates are often stable with respect to hydrolysis.
α-Phenylseleno aldehydes, which are usually prepared from the corresponding enol ethers, are usually oxidized with mCPBA or ozone, as hydrogen peroxide causes over-oxidation. α-Phenylseleno ketones can be prepared by kinetically controlled enolate formation and trapping with an electrophilic selanylating reagent such as benzeneselenyl chloride.
Although many different peroxyacids are used for the Baeyer–Villiger oxidation, some of the more common oxidants include meta-chloroperbenzoic acid (mCPBA) and trifluoroperacetic acid (TFPAA). [2] The general trend is that higher reactivity is correlated with lower pK a (i.e.: stronger acidity) of the corresponding carboxylic acid (or alcohol ...
This observation is attributed to a balance of two factors. The first is the stabilization of the transition state as a result of the hydrogen bonding. The second is the electron-withdrawing nature of the oxygen, which draws electron density away from the alkene, lowering its reactivity. [5] Acyclic allylic alcohols exhibit good selectivity as ...
A generic epoxide. In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen.This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ethers.