I have a question about the selectivity of m-CPBA in this reaction. In my experience, I have used m-CPBA for epoxidation of alkenes. It surprised me that in this reaction, the ketone reacts to give an ester and the alkene remains unchanged? Is it due to the presence of the overhanging ether group? Does this provide a sort of steric crowding so that the peroxyacid can't get in? Cheers.enter image description here

  • $\begingroup$ Did you make two accounts? I may cause problems... $\endgroup$
    – Mithoron
    Apr 6 '17 at 19:01

The transformation taking place in your question is a name reaction known as a Baeyer-Villiger.

The Baeyer-Villager transforms ketones into esters/lactones (cyclic esters) via an alkyl migration in which the group most able to stabilise a positive charge is observed to migrate.

A general mechanism is presented below (taken from the wonderful name reactions book cited). The key steps are (1) attack of the peroxide into the carbonyl followed by (2) the alkyl migration to form the ester grouping.

enter image description here Source: Strategic Applications of Name Reactions, 2005.

  • 1
    $\begingroup$ That is great-thank you for the reference and mechanism of tranforming the ketone to an ester. However, I am still unclear why the peroxyacid selects the ketone functional group over the alkene-is it simply more reactive? $\endgroup$
    – gamma1
    Apr 6 '17 at 17:57
  • $\begingroup$ Its not always clear cut which will happen. Fundamentally it depends on the specific alkene and the specific carbonyl. $\endgroup$
    – NotEvans.
    Apr 6 '17 at 17:59

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