Advances in [1,2]-Sigmatropic Rearrangements of Onium Ylides via Carbene Transfer Reactions

Abstract This review article summarizes progress made on [1,2]-sigmatropic rearrangements using carbenes in the ylide formation step. While other rearrangements, such as the [2,3]-sigmatropic, Doyle–Kirmse, or Sommelet–Hauser rearrangements, have been studied in detail over the past decades, investigations on [1,2]-sigmatropic rearrangements are still limited. Based on the application of diazoalkanes as carbene precursors, research on diazoalkanes in ylide formation reactions started flourishing in the 1990s. This Short Review covers milestones from the advent of [1,2]-sigmatropic rearrangements using carbenes to generate ammonium, oxonium and other ylide species, and should serve as an overview to further promote research in this area. 1 Introduction 2 Ammonium Ylides 3 Oxonium Ylides 4 Sulfonium and Selenium Ylides 5 Halonium Ylides 6 Conclusion and Outlook