Kornblum–DeLaMare rearrangement
The Kornblum–DeLaMare rearrangement is a
The base can be a hydroxide such as potassium hydroxide or an amine such as triethylamine.
Reaction mechanism
In the reaction mechanism for this organic reaction the base abstracts the acidic α-proton of the peroxide 1 to form the carbanion 4 as a reactive intermediate which rearranges to the ketone 2 with expulsion of the hydroxyl anion 3'. This intermediate gains a proton forming the alcohol 3.
Deprotonation and rearrangement can also be a concerted reaction without formation of 4.
An alternative reaction mechanism involving direct
The peroxide 1 converts to the hydroxyketone 2 by action of
The reaction, formally a rearrangement, ranks under the elimination reactions as already observed by the original authors. Not only alkoxides but any leaving group capable of carrying a negative charge will do for instance nitrate esters R–C(R)(H)–O–NO2.
Related reactions
The corresponding reaction involving an ether is the 1,2-Wittig rearrangement. The reaction course in this rearrangement is different because ether cleavage with carbanion formation is unfavorable. The Pummerer rearrangement in one of its reaction step contains a sulfur variation.
Scope
The original 1951 publication concerned the conversion of potassium t-butyl peroxide and 1-phenylethyl bromide to ultimately
The Kornblum–DeLaMare rearrangement can be carried out as an
The first step in this