Metal-Free Chemoselective S-Arylation of Sulfenamides To Access Sulfilimines

Abstract

A novel and efficient S-arylation of sulfenamides with diaryliodonium salts for the synthesis of sulfilimines is developed. The reaction proceeds smoothly under transition-metal-free and air conditions, giving rapid access to sulfilimines in good to excellent yields via selective S–C bond formation. This protocol is scalable and exhibits a broad substrate scope, good functional group tolerance, and excellent chemoselectivity.

A combined experimental and computational study of ligand-controlled Chan-Lam coupling of sulfenamides

“…From the standpoint of organic chemistry, they continue to elicit interest due to their utility as protecting groups in peptide synthesis and their stereochemical properties arising from hindered rotation about the S-N bond 1 . Very recently, we and other groups have exploited sulfenamides as a versatile reagent to prepare other organosulfur pharmacophores with higher oxidation states, such as S(IV)-derived sulfilimines and S(VI)derived sulfoximines [10][11][12][13][14][15][16] . Notably, C-S bond forming pathways override the alternative C-N bond formation processes either in the presence of transition-metal catalysts or under transition-metal-free conditions.…”

“…1A, b). Despite this appeal, C-N arylation of NH-sulfenamides has not been explored previously, to the best of our knowledge, primarily due to the fact that transitionmetal-catalyzed or transition-metal-free functionalization of NH-sulfenamides prefers to take place on the sulfur site rather than the nitrogen site [10][11][12][13][14][15][16] , even though N-functionalization is thermodynamically favored 11 . Furthermore, the S-N bond of sulfenamides is notoriously labile, as it is prone to hemolysis under thermal or photoinduced conditions 19 or heterolysis in the presence of nucleophiles or electrophiles (Fig.…”

Synthesis of Sulfilimines via Multicomponent Reaction of Arynes, Sulfamides, and Thiosulfonates

“…Subsequently, the Cu-catalyzed sulfur arylation of sulfenamides through Chan–Lam-type and Ullmann-type coupling were independently reported by Jia, Kozlowski, and Ellman . At the same time, base promoted sulfur alkylation and arylation of sulfenamides with alkyl halides and diaryliodonium salts were disclosed by Li, Lu, Ellman, Yang, and Wu . Although great achievements have been made for construction of sulfilimines, the development of a more efficient and facile methodology for the preparation of this vital class of compounds is still highly desirable.…”

Synthesis of Sulfilimines via Aryne and Cyclohexyne Intermediates

“…However, to the best of our knowledge, the utilization of aryne intermediates for the synthesis of sulfilimines has not been explored. Inspired by the recent advances in the transformation of sulfenamides and our continuous interest in the field of organosulfur chemistry, , we speculated that the reaction between sulfenamides and aryne precursors would be an attractive and complementary approach to access sulfilimines. Given the significance of sulfilimine scaffolds, herein we report a metal-free and efficient method for the synthesis of sulfilimines from sulfenamides and arynes under mild conditions, providing the desired products in moderate to good yields with excellent chemoselectivity (Scheme b).…”