Mislow–Evans Rearrangement and Mechanism

Mislow–Evans Rearrangement

Mislow–Evans rearrangement is a thermal [2,3]-sigmatropic rearrangement of an allylic sulfoxide to a sulfenate ester which is unstable and is cleaved to yield an allylic alcohol. This rearrangement named after Kurt Mislow, who first reported on it in 1966, and David A. Evans, who further developed its synthetic utility in 1971.

The Mislow–Evans rearrangement is highly stereoselective. The chirality at the sulfur atom of the sulfoxide can be efficiently transferred to a new stereocenter on the carbon next to the oxygen in the allylic alcohol product. The reaction favors the formation of trans-allylic alcohols.

Mechanism of Mislow–Evans Rearrangement

The mechanism starts with an allylic sulfoxide which undergoes a thermal [2,3]-sigmatropic rearrangement to give a sulfenate ester which is cleaved using phosphite ester and leaves the trans-allylic alcohols as the product as shown below-