Desulfonylation Reactions

Abstract

The use of sulfones in organic chemistry, acting as an auxiliary group, is still a very important synthetic strategy, especially for the formation of carbon‐carbon single and double bonds. Once the synthetic objective is achieved, the sulfone gruop is usually removed from the molecule. This removal most commonly involves a reductive desulfonylation process with either replacement of the sulfone by hydrogen, or a process that results in the formation of a carbon‐carbon double bond when a β‐hydroxy or β‐alkoxy sulfone is employed. This chapter is devoted to the replacement of the sulfone group by a hydrogen (reductive desulfonylation reactions), and reductive elimination reactions of Julia‐type substrates (Julia‐Lythgoe olefination process). The chapter addresses the full scope, generality, limitations, and synthetic applications of these reactions. The literature through most of 2007 is covered.

Aromatic C–H Methylation and Other Functionalizations via the Rh(III)-Catalyzed Migratory Insertion of Bis(phenylsulfonyl)carbene and Subsequent Transformations

“…The results are summarized in Scheme . Two desulfonylation methods (A, SmI 2 /HMPA/THF; B, Mg/CH 3 OH) were selected on the basis of previous studies. , For most substrates, method A provided better yields. In a few cases, method B worked better.…”

“…Bis­(sulfonyl)­methyl groups are a kind of versatile synthons and are widely used for the synthesis of bioactive compounds and natural products . They are readily transformed to methyl groups via desulfonylation with metals or other reductants . Further transformations to trideuteriomethyl, monosulfonylmethyl, carboxylic acids, and aldehydes were developed …”

One and Two-Carbon Homologation of Primary and Secondary Alcohols to Corresponding Carboxylic Esters Using β-Carbonyl BT Sulfones as a Common Intermediate

“…Finally, the desulfonylation of the intermediate 8 was attempted using metal-mediated reductive conditions. Since many metals are known to promote desulfonylation of β-carbonyl phenyl sulfones, we expected that the identification of the suitable conditions would be rather easy. Surprisingly this was not the case, and only SmI 2 /MeOH and Zn dust /AcOH systems were able to yield the desired desulfonylated products in good to excellent yields (Table , Methods D and E) .…”

Synthesis of quaternary centres by single electron reduction and alkylation of alkylsulfones

“…1 Due to the inherent stability of sulfonyl groups, strong reducing agents such as Na amalgam and Mg are generally required for their removal (Scheme 1). 2 However, a stepwise alkylative desulfonylation process would be much more valuable. In this process, single electron transfer to the sulfonyl group by a reductant would fragment into a sulnic anion and a sp 3 -carbon radical, which could be trapped with organic electrophiles rather than merely reduced and protonated.…”