Recent Developments in Vinylsulfonium and Vinylsulfoxonium Salt Chemistry

Abstract

This review describes advances in the literature since 2000 in the area of reactions of vinylsulfonium and vinylsulfoxonium salts, with a particular emphasis on stereoselective examples. Although the chemistry of vinylsulfonium salts was first explored back in the 1950s, and that of vinylsulfoxonium salts in the early 1970s, there has been renewed interest in these compounds since the turn of the century. This has been largely due to an increased appreciation for the many synthetic possibilities associated with these valuable electrophiles. The development of improved routes to vinylsulfonium salts allowing for their in situ generation has played a part in accelerating their study. In general, reactions of the two sulfur salt classes follow a similar mechanistic pathway: initial conjugate addition of a nucleophile to the β-position, followed by protonation of an ylide intermediate, and cyclization of tethered anion to afford monocyclic or bicyclic product (e.g. cyclopropane, aziridine, oxazole, oxazolidinone, γ-lactam or γ-lactone). Alternatively, reactions involve formation of a ylide intermediate followed by intramolecular Johnson-Corey-Chaykovsky reaction (epoxidation or cyclopropanation), and subsequent cyclization to afford the desired bicyclic product (e.g. fused bicyclic epoxide or cyclopropane).

Selenonium Ylides: Syntheses, Structural Aspects, and Synthetic Applications

“…The purpose of this mini review was to provide the available information on all topics mentioned above in order to stimulate additional research in this field. The rationale for this research topic is the structural similarity between selenonium ylides and sulfonium ylides, which play a very important role as new synthetic reagents, biologically active compounds, and new functional materials [4][5][6][7][8]. Therefore, it is reasonable to expect that achiral and optically active selenonium ylides should be just as useful as sufonium ylides when they have sufficiently high chemical and optical stability.…”

“…After looking at the structure of sulfonium ylides (Figure 2), which constitute the basic group of sulfur ylides [4][5][6][7][8], it is obvious to consider them as a reference point for selenonium ylides (Figure 1). This is due to the fact that their reactivity is dominated mainly by the presence of a highly It is worth noting that for this family of selenoorganic derivatives, adopting resonance structure 1 allows formal consideration of these compounds as the group of trivalent tri-coordinated onium salts.…”

“…After looking at the structure of sulfonium ylides (Figure 2), which constitute the basic group of sulfur ylides [4][5][6][7][8], it is obvious to consider them as a reference point for selenonium ylides (Figure 1). This is due to the fact that their reactivity is dominated mainly by the presence of a highly polarized heteroatom-carbon bond, and their chirality is associated with their tetrahedral geometry, which induces the optical activity of compounds in which three different carbon chains or/and rings are bonded to a stereogenic heteroatom.…”

“…Below, we are going to discuss the synthesis of selenonium ylides (achiral, racemic, and optically active), their structural parameters and selected reactivities, and their application in general and asymmetric syntheses. In fact, studies devoted to sulfur ylides, especially optically active derivatives, are much richer compared to selenium analogues [4][5][6][7][8]. The best illustration of this phenomenon may be the comparison of the number of documents, which can be obtained by entering the terms "sulfur ylides" and "selenium ylides" or their general drawings to SciFinder or Reaxys databases (close 1 to 6, i.e., around 500 for sulfur ylides and 85 for selenium ylides).…”

Synthesis of Pyridylsulfonium Salts and Their Application in the Formation of Functionalized Bipyridines

“…Sulfonium salts have garnered considerable attention of late in organic synthesis, especially for their utility in mediating C–C bond formation (Scheme ). , Examples using sulfonium salts bearing sp 2 -hybridized carbon substituents include reactions of vinylsulfonium salts to generate pharmaceutically relevant heterocycles, cross-couplings, and transformations using the extremely versatile thianthrenium and benzothiophenium salts . Triarylsulfonium salts have been demonstrated to be particularly versatile reagents, capable of forming C–C bonds via various different methods. ,, …”