Copper-Catalyzed Regioselective Intramolecular Electrophilic Sulfenoamination via Lewis Acid Activation of Disulfides under Aerobic Conditions

Abstract

The activation of disulfides by Cu(II) salts has been realized, which triggers a highly efficient electrophilic sulfenoamination of alkenes under aerobic conditions. Various sulfenyl N-heterocycles and their Selena counterparts were produced regioselectively, with no competing disulfidation products detected. Mechanistic studies suggest a profound influence of the counterions on the Lewis acidic copper center, and the important roles of oxygen and DMSO as co-oxidants for these cyclization processes.

Alkyl Sulfides as Promising Sulfur Sources: Metal‐Free Synthesis of Aryl Alkyl Sulfides and Dialkyl Sulfides by Transalkylation of Simple Sulfides with Alkyl Halides

“…Conventional approaches for alkyl‐sulfur bond formation are mainly based on substitution reactions of nucleophilic sulfur reagents such as metal sulfides, thiosulfates, thiourea, thiol derivatives with electrophilic alkylating reagents. The reactions of inverse polarity, i. e. between electrophilic sulfuration reagents such as sulfenyl halides, or disulfides and alkyl nucleophiles or olefins also make convenient routes. Radical reactions also provide useful methods for alkyl sulfide synthesis .…”

Recent advances in tandem selenocyclization and tellurocyclization with alkenes and alkynes

“…In 2018, Zhong and co-workers developed a copper-catalyzed tandem selenoamination reaction of alkenes, successfully affording a series of seleno-N-heterocycles (e.g., indoline, tetrahydroquinoline, pyrroline, and piperidine derivatives) with 73-93% yields (Scheme 13). 23 In this approach, 10 mol% of CuBr 2 was utilized in DMSO at 120°C in air. During the mechanistic investigation, oxygen and DMSO as co-oxidants were necessary for this transformation.…”

“…The mechanism for this intramolecular selenoamination is similar to that described in Zhong's work. 23 In 2018, Xu and co-workers demonstrated a selenocyclization of 2,3-allenoic acids 47 with diselenides in the combination of CuCl and (NH 4 ) 2 S 2 O 8 as catalytic oxidation system (Scheme 15). 25 The reaction enabled sulfenylation/cyclization and subsequent oxidation to provide selenylated butenolides 48 in 63-82% yields.…”

Catalytic Electrophilic C–H Sulfenylation of Indoles with Disulfides under Ball Milling

“…Despite interesting values of these insights with respect to protein function regulation and rational design of mechanoresponsive materials in a macromolecular context, the synthetic potential of mechanoactivation of disulfides for synthetic sulfenylation reaction remains underexploited. As a part of our research interest in preparing biologically valuable organosulfur compounds based on disulfide reagents, , herein we present the first mechanochemical electrophilic C–H sulfenylation by merging iodine catalysis and ball milling activation which not only enhances S–S bond polarity but also fosters an event of aerobic oxidation, thus rendering a high atom-economic harness of the sulfur reagent under metal-free benign conditions (Figure b).…”