Redox-Neutral Synthesis of Sulfilimines through the S-Alkylation of Sulfenamides

Abstract

In this work, we developed a metal-free and redoxneutral strategy for the selective S-alkylation of sulfenamides under basic conditions to yield sulfilimines. The key step involves the resonance between bivalent nitrogen-centered anions, generated after deprotonation of sulfenamides under alkaline conditions, and sulfinimidoyl anions. Our sustainable and efficient approach employs sulfur-selective alkylation of readily accessible sulfenamides and commercially available halogenated hydrocarbons, resulting in the successful synthesis of 60 sulfilimines in high yields (36−99%) and short reaction times.

Sulfilimine bond formation in collagen IV

“…This is considered one of the earliest examples of a synthetically created N–S bond-containing natural product known for its antioxidant and antimicrobial properties. 68 More recently, in 2023, Huang et al 69 developed a metal-free and redox-neutral strategy for the selective S -alkylation of sulfenamides under basic conditions, resulting in the formation of sulfilimines. Their study involved resonance between bivalent nitrogen-centered anions, generated after deprotonation of sulfenamides under alkaline conditions, and sulfinimidoyl anions.…”

1,2-Difunctionalization of Aryne with Sulfenamide and Organohalide: Mild and Metal-Free Access to S-(o-Halo)aryl Sulfilimine

“…Considering the importance of sulfilimines, many protocols have been developed for their preparation. The most common reports include the imination of sulfide or arylation/alkylation of sulfenamide. ,− It is worth mentioning that in 2023 there was a sudden surge in sulfilimine preparation via S-functionalization of sulfenamide. ,− Very recently, the groups of Tan and Wu have independently prepared sulfilimine via the reaction of sulfenamide and aryne. Nevertheless, our focus extends beyond just the preparation of sulfilimine; it involves the incorporation of an extra reactive handle (halogen) into it via a one-pot method.…”