Enantioselective S−H Insertion Reactions of α‐Carbonyl Sulfoxonium Ylides

Solvent-free, B(C6 F5 )3 -Catalyzed S-H Insertion of Thiophenols and Thiols with α-Diazoesters

Described herein is a B(C₆ F₅ )₃ -catalyzed S-H insertion reaction of thiophenols and thiols with α-diazoesters to access valuable α-thioesters. With the established protocol, an array of α-thioester products are generated in moderate to good yields with broad scope and functional group tolerance. In addition, this reaction maintains its high efficiency on gram scale and the product can be easily transformed into other useful motifs. This reaction proceeds under solvent-free conditions at room temperature, and generally finishes in twenty minutes upon magnet stirring, which offers an expedient way for synthesis of thioether-containing compounds.

Insights into the Activation Mode of α-Carbonyl Sulfoxonium Ylides in Rhodium-Catalyzed C-H Activation: A Theoretical Study

A computational study has been performed to investigate the mechanism of Rh^III‐catalyzed C−H bond activation using sulfoxonium ylides as a carbene precursor. The stepwise and concerted activation modes for sulfoxonium ylides were investigated. Detailed theoretical results showed that the favored stepwise pathway involves C−H bond activation, carbonization, carbene insertion, and protonation. The free energy profiles for dialkylation of 2‐phenylpyridine were also calculated to account for the low yield of this reaction. Furthermore, the substituent effect was elucidated by comparing the energy barriers for the protonation of meta‐ and para‐substituted sulfoxonium ylides calculated by density functional theory.