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The reaction proceeds through what is commonly known as the "butterfly mechanism", first proposed by Bartlett, wherein the peracid is intramolecularly hydrogen-bonded at the transition state. [5] Although there are frontier orbital interactions in both directions, the peracid is generally viewed as the electrophile and the alkene as the ...
Through a concerted mechanism, one of the substituents on the ketone group migrates to the oxygen of the peroxide group while a carboxylic acid leaves. [1] This migration step is thought to be the rate determining step. [2] [3] Finally, deprotonation of the oxocarbenium ion produces the ester. [1] Reaction mechanism of the Baeyer-Villiger ...
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 mechanism of epoxidation with dioxiranes likely involves concerted oxygen transfer through a spiro transition state. As oxygen transfer occurs, the plane of the oxirane is perpendicular to and bisects the plane of the alkene pi system. The configuration of the alkene is maintained in the product, ruling out long-lived radical intermediates.
In the elimination reaction, all five participating reaction centers are coplanar and, therefore, the reaction stereochemistry is syn. Oxidizing agents used are hydrogen peroxide, ozone or MCPBA. This reaction type is often used with ketones leading to enones. An example is acetylcyclohexanone elimination with benzeneselenylchloride and sodium ...
However it has been shown that for medium-sized rings (eight and nine) peracid oxidizers show reverse selectivity, while vanadium catalyzed reactions continue to show formation of the syn epoxide. [14] Although it is the least reactive metal catalyst for epoxidations, vanadium is highly selective for alkenes with allylic alcohols.
While the Rubottom oxidation generally gives good yields and is highly scalable (see 2S-hydroxymutilin synthesis), there are still some problems with the reaction. As mentioned above, the acidic reaction conditions are not tolerated by many complex substrates, but this can be abrogated with the use of buffer systems. [1]
This mechanism, which was originally proposed by John Groves to explain porphyrin-catalyzed epoxidation reactions, [9] is commonly referred to as a "side-on perpendicular approach". The approach is over the diamine bridge, where the steric bulk of the tert-butyl groups on the periphery of the ligand do not interfere with the alkene's approach ...