Synthesis of Sulfilimines via Aryne and Cyclohexyne Intermediates

Abstract

An efficient and metal-free approach for the synthesis of sulfilimines from sulfenamides with aryne and cyclohexyne precursors has been developed. The reaction proceeds through unusual S–C bond formation, which offers a novel and practical entry to access a wide range of sulfilimines in moderate to good yields with excellent chemoselectivity. Moreover, this protocol is amenable to gram-scale synthesis and is applicable to the transformation of the products into useful sulfoximines.

Decarboxylative Radical Sulfilimination via Photoredox, Copper, and Brønsted Base Catalysis

“…[10] Despite Grignard reagents were widely used in organic chemistry, their use was limited by strictly anhydrous and anaerobic conditions. Very recently, sulfilimines have been synthesized from sulfenamides via nucleophilic reactions, Chan-Lam-type reactions, and Ullmann-type reactions by the groups of Ellman, [11] Jia and Kozlowski et al, [12] Wu, [13] and others (Figure 1B-d). [14] However, radical-based methods for accessing sulfilimines have not been reported, despite the spurt of progress in the generation of alkyl radicals from various types of organic compounds.…”

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

“…10,18−23 It is worth mentioning that in 2023 there was a sudden surge in sulfilimine preparation via S-functionalization of sulfenamide. 10,18−23 Very recently, the groups of Tan 24 and Wu 25 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.…”

“…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.…”