Julia Olefination

AbstractThe multistep preparation of trans‐olefins involving the addition of phenylsulfonyl carbanion to aldehydes or ketones to form β‐hydroxysulfones, followed by the esterification of hydroxyl group and reductive elimination of β‐sulfonyl esters with sodium amalgam is generally referred to as the Julia olefination. Because of its intrinsic weaknesses, Julia olefination protocol has been extensively modified and extended. These modifications employ the one‐step reaction between heterocyclic sulfonyl carbanion and aldehyde (or ketone) to give eithercis‐ ortrans‐olefins or replace the reduction from the sodium amalgam by samarium iodide (SmI2). Therefore, the modified olefination methods are referred to as the Kocienski olefination. Several heterocyclic sulfones in this olefination reaction have been suggested and it has been reported that the application of heterocyclic sulfones in this olefination provides extra advantages. This reaction has wide application in the preparation of olefins, particularly in the convergent synthesis of complex natural products.