Iodine‐Catalyzed One‐Pot Decarboxylative Sulfenylation of Electron‐Rich Arenes and Indoles

Abstract

Elemental iodine catalyzed decarboxylative sulfenylation (mono‐ or di) of electron‐rich alkoxybenzoic acids using benzenesulfonohydrazides as sulfenylating agent for the synthesis of diaryl sulfides under transition metal‐free conditions has been described. The method also works for the decarboxylative thioarylation (mono‐ or di) of indole carboxylic acids. Reactions showed very good functional group tolerance and excellent yields of sulfinylated products.

Controllable Synthesis of Mono‐ and Bis‐sulfenylindoles from Indoles and Various Sulfenylation Agents Using KI/SeO2 System

“…In addition, a variety methods have been established for sulfenylation of indoles using various sulfenylating reagents such as thiol, [5,6] disulfide, [5,7] Bunte salts, [5,8] sulfonylhydrazide, [9] sulfenyl halides [10] and sulfur powder [11] . Moreover, the methods for synthesis of bis‐sulfenylindoles have been reported via sulfenylation of indoles with thiophenols, [12] sulfonylhydrazide [9a] and sodium sulfinates [13] . Thiols and disulfides are becoming interesting reagents because of their ready availability and atom‐economical sulfenylation process.…”

Decarboxylation‐Initiated Intermolecular Carbon‐Heteroatom Bond Formation

“… [302] Analogous selenations were also applicable, but only moderate yields were obtained with diphenyl diselenide and attempts with other diaryl diselenides led to low yields. Replacing diaryl disulfides with benzenesulfonohydrazides as the thiolating sources allows an I 2 ‐catalyzed decarboxylative functionalization of alkoxybenzoic acids and indole carboxylic acids [303] . Cu(I)‐based peptide nanofibers were found to be efficient, recyclable catalysts for three‐component decarboxylative C−S coupling of benzoic acids and aryl halides with octasulfur (S 8 ) as the sulfur source [304] .…”

Sulfenylation of Indoles Mediated by Iodine and Its Compounds

“…Sodium iodide was applied as a reductant in CeCl 3 ‐catalyzed sulfenylation of indoles with aromatic and aliphatic sulfonyl hydrazides [62] . The reaction between 3‐carboxy indole with sulfonyl hydrazides in the presence of I 2 in 1,4‐dioxane at 100 °C delivered 2,3‐disulfenylated indole derivatives in 78–94 % yields [63] . This process was accompanied by decarboxylation, its mechanism is similar to that described above (Scheme 18).…”