PrilezhaevOxidation

The Prilezhaev reaction, also known as epoxidation, is a chemical reaction in which an alkene is converted into an epoxide using a peroxy acid. The most common peroxy acid used in this reaction is meta-chloroperoxybenzoic acid (m-CPBA), although peroxyacetic acid and peroxyformic acid can also be employed. The reaction is named after the Russian chemist Nikolai Prilezhaev, who first described it in 1909.

The mechanism of the Prilezhaev reaction involves a concerted, one-step process. The peroxy acid acts as an electrophile, and the pi electrons of the alkene act as a nucleophile. The oxygen atom of the peroxy acid is transferred to one of the carbon atoms of the double bond, while a proton is transferred to the carbonyl oxygen of the peroxy acid. This results in the formation of a three-membered cyclic ether, the epoxide, and the corresponding carboxylic acid.

The Prilezhaev reaction is highly regioselective and stereoselective. It generally proceeds with syn-addition, meaning that the oxygen atom is added to the same face of the double bond. The reaction is also effective for a wide range of alkenes, including those with electron-donating or electron-withdrawing substituents. The epoxides formed are valuable intermediates in organic synthesis, as they can be further transformed into a variety of functional groups, such as diols, halohydrins, and amines. The reaction's utility and relative simplicity have made it a cornerstone in synthetic organic chemistry.