The addition of a peroxyacid to an alkene converts the alkene to an epoxide.
The mechanism for question #22 on Sapling Chapter 6 (Practice) is shown below.
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A peroxyacid contains one more oxygen than a carboxylic acid. This is very important for this mechanism, because that is the oxygen that is transferred to the alkene to form an epoxide. The oxygen is electrophilic. The nucleophilic pi bond donates its electrons to the oxygen, breaking the O-O bond to form the synthesize the carbonyl bond. The electrons from the old O-H bond make up the second new C-O bond, and the original carbonyl group uses its electrons to pick up the proton. Epoxidation is a concerted oxidation reaction. The epoxide now contains a new 3 membered ring as shown. The basis of the mechanism is an electrophilic attack with a proton being transferred from the epoxide oxygen to the carboxylic acid by-product.
References
Electrophilic Addition to Alkenes
Epoxide Synthesis by Epoxidation
I find this to be very well done and quite thorough. I don't think became 100% with chemdraw and think this post shows a much greater ability with the software than I have. Secondly, it is interesting to see the actual process of the addition of a peroxyacid to an alkene.
ReplyDeleteThis was a great post and a really good walk through. It described the process very well, and made many points much clearer, such as the movement of electrons.
ReplyDeleteWow, you did a very good job of laying out the mechanism for peroxyacid using chemDraw. This is a nice refresher on peroxyacid, especially of knowing where the electrons are moving and what bonds are formed.
ReplyDeleteThis was a very good explanation to the problem. This one gave me a hard time and I'm not sure if I even got it right on the homework but I 100% understand it better after reading this. Good Job.
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