Organocatalytic Asymmetric X–H Insertion Reactions of α-Carbonyl Sulfonium Ylides, Sulfoxonium Ylides, and Sulfonium Salts

Abstract Since their initial discovery by Ingold and Jessop in 1930, sulfur ylides have been recognized as a highly versatile class of compounds in organic synthesis. Their reactivity, which closely resembles that of diazo compounds, has enabled them to serve as valuable surrogates for safe and stable carbene precursors, offering unique advantages in large-scale syntheses. However, compared to diazo compounds, the catalytic asymmetric reactions involving sulfur ylides, whether as substrates or intermediates, remain relatively underexplored. In this account, we mainly summarize our recent advancements in this area, focusing particularly on their applications in organocatalytic asymmetric X–H (X = N, N3, Cl, and C) insertion reactions. These reactions typically involve enantio-determining and rate-determining C–X bond formation in combination with dynamic kinetic resolution, thus leading to both high chemical efficiency and enantiocontrol. 1 Introduction 2 S–H Insertion Reactions of Sulfoxonium Ylides 3 N–H Insertion Reactions of Sulfonium Ylides 4 N–H Insertion Reactions of Sulfoxonium Ylides 5 One-Pot Sequential Ylide Formation and N–H insertion Reactions 6 N3–H Insertion Reactions of Sulfoxonium Ylides 7 Chlorination of Sulfonium Salts 8 C–H Insertion Reactions of Sulfoxonium Ylides 9 Conclusion and Outlook