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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 ...
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]
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.
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.
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 ...
A number of other reagents bring about this reaction. Scheme 1. Selenium dioxide oxidation. In terms of reaction mechanism, SeO 2 and the allylic substrate react via pericyclic process beginning with an ene reaction that activates the C−H bond. The second step is a [2,3] sigmatropic reaction.
An enal (or alkenal) is an organic compound containing both alkene and aldehyde functional groups. In an α,β-unsaturated enal, the alkene is conjugated to the carbonyl group of the aldehyde (formyl group). [3] The simplest enal is acrolein (CH 2 =CHCHO). Other examples include cis-3-hexenal (essence of mowed lawns) and cinnamaldehyde (essence ...
Reactions where the stereochemistry of the hydroxyl group is inverted saw lower regioselectivity, and removal of the hydroxyl group gave the exclusive formation of the other regioisomer. It is likely that the close proximity of the hydroxyl group in the syn isomer acidifies the ring-fusion proton through hydrogen-bonding interactions, thus ...