Mislow–Evans rearrangement
Reaction in organic chemistry
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The Mislow–Evans rearrangement is a name reaction in organic chemistry.[1] It is named after Kurt Mislow who reported the prototypical reaction in 1966,[2] and David A. Evans who published further developments.[3]
General reaction scheme
The reaction allows the formation of allylic alcohols from allylic sulfoxides by a 2,3-sigmatropic rearrangement. The conversion can be highly diastereoselective as the chirality at sulphur atom can be transmitted to the carbon next to the oxygen in the product.
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The sulfoxide 1 reagent can be generated easily and enantioselectively from the corresponding sulfide by an oxidation reaction.[4] In this reaction various organic groups can be used, R1 = alkyl, allyl and R2 = alkyl, aryl or benzyl
Mechanism
A proposed mechanism is shown below:[4]
The mechanism starts with an allylic sulfoxide 1 which undergoes a thermal 2,3-sigmatropic rearrangement to give a sulfenate ester 2. This can be cleaved using a thiophile, such as phosphite ester, which leaves the allylic alcohol 3 as the product.[5]
Scope
The reaction has general application in the preparation of trans-allylic alcohols.[6] Douglass Taber used the Mislow–Evans rearrangement in the synthesis of the hormone prostaglandin E2.[4]