Mislow–Evans rearrangement

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.

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]

References

  1. ^ Li, Jie Jack (2006). Name Reaction. Springer Publishing. p. 388. doi:10.1007/3-540-30031-7_174. ISBN 978-3-540-30030-4.
  2. ^ Mislow, Kurt (1966). "Mechanisms of Thermal Racemization of Sulfoxides". Journal of the American Chemical Society. 88 (13): 3138–3139. doi:10.1021/ja00965a048.
  3. ^ Evans, David A. (1971). "Reversible 1,3 transposition of sulfoxide and alcohol functions. Potential synthetic utility". Journal of the American Chemical Society. 93 (19): 4956–4957. doi:10.1021/ja00748a075.
  4. ^ a b c Kürti, László; Czakó, Barbara (2005). Strategic applications of named reactions in Organic Synthesis. Elsevier. p. 292. ISBN 9780124297852.
  5. ^ Evans, David; Andrews, Glenn (1974). "Allylic sulfoxides. Useful intermediates in organic synthesis". Accounts of Chemical Research. 7 (5): 147–155. doi:10.1021/ar50077a004.
  6. ^ Zerong Wang (2009), Comprehensive Organic Name Reactions and Reagents (in German), New Jersey: John Wiley & Sons, pp. 1991–1995, ISBN 978-0-471-70450-8
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