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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.
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.
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.
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 well. In these systems both A 1,2 (steric interactions with vinyl) and A 1,3 strain are considered.
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 ...
The silyl enol ether was then treated with excess mCPBA to facilitate a “double” Rubottom oxidation to give the exo product with both hydroxyl groups on the outside of the fused ring system. This dihydroxy product was then transformed into Velutinol A in three additional steps.