The Julia–Kocienski olefination is a direct connective synthesis of alkenes via the addition of metalated aryl alkyl sulfones to carbonyl compounds. The activating aromatic group associated with the sulfone must possess electrophilic character, and alkene formation occurs via β-alkoxy sulfone formation, transfer of the aryl group from sulfur to oxygen via a Smiles rearrangement, and then elimination of sulfur dioxide and an aryloxide anion from the resulting β-aryloxy sulfinate anion. The olefination process itself and the methods used to prepare the requisite sulfone substrates are tolerant of a wide variety of functional groups, and a variety of alkene targets can be prepared. Stereoselectivity is dependent on the nature of the sulfone, the carbonyl compound, the activating aryl moiety, and the reaction conditions.
This chapter describes theoretical and operational aspects of the Julia–Kocienski olefination such that the reader will be able to obtain optimal results in his/her own research. A detailed mechanistic overview is included to account for the factors that influence stereoselectivity and yield. Methods for introducing sulfone activators into fragments of interest, best practices for generating sulfone anions, and optimal strategies for targeting different classes of alkene targets are discussed. Functional group compatibilities, reaction variants, and a comparison to other methods of alkene synthesis are also presented. Tabular surveys are organized according to type of alkene synthesized, with an emphasis on the degree of substitution and the level of conjugation about the newly formed double bond. The literature is covered from the initial disclosure of the Julia–Kocienski olefination in 1991 to the first quarter of 2016.