Sulfur Ylides as C 1 Homologating Reagents

Abstract

The introduction of complementary reactivities or reagents to well-established activation modes or organic reactions is always in the spotlight of organic synthesis. The C1 homologation reactions play a pivotal role, since they expand by one-carbon atom the carbon scaffold. Since their introduction in the early 1960s, sulfur and sulfoxonium ylides have been studied extensively for their elegant properties and efficiency on C1 homologation of different moieties. In this chapter, the similarities and differences on the reactivity of sulfur and sulfoxonium ylides are provided. Their exceptional ease on transformations, like the epoxidation of carbonyl compounds, the aziridination of imines, the cyclopropanation of electron-rich alkenes, and many more, is presented. Whenever attempts to make these reactions asymmetric were made are properly reviewed, while other ring expansion or miscellaneous reactions are supplied.