Ag/K₂S₂O₈‐Mediated Direct Thiolation and Selenylation of Carbazoles

Abstract

The first direct and selective 3,6-di-thiolation and 3,6-diselenylation of carbazoles using diaryl disulfides/diselenide as the sulfur/selenium source were demonstrated. This simple, general, and efficient method could deliver a wide range of 3,6-di-sulfenyl-carbazoles and 3,6-di-selenyl-carbazoles from readily available starting materials with high regioselectivity in an easily-operated one-step reaction via a Ag/K 2 S 2 O 8 -mediated protocol.

Trifluoromethylthiolation of Arenes Using Lewis Acid and Lewis Base Dual Catalysis

“…26 Recently, Jiang and co-workers highlighted the importance of thiolated carbazoles for a variety of applications and reported a direct 3,6-dithiolation reaction using AgSbF 6 (30 mol %), potassium persulfate and diaryl disulfides as the sulfur source. 34 To complement this study, we were interested to discover whether our dual catalytic method could be used for the selective preparation of monothioarylated products (Scheme 3). The reaction of carbazole (8a) with Ntrifluoromethylthiosaccharin (4) using a 5 mol % catalyst loading and at room temperature required a reaction time of 7 h. Only one product, 3-trifluoromethylthiolated isomer 10a, was observed by 1 H NMR spectroscopy, which was isolated in 82% yield.…”

“…Recently, Jiang and co-workers highlighted the importance of thiolated carbazoles for a variety of applications and reported a direct 3,6-dithiolation reaction using AgSbF 6 (30 mol %), potassium persulfate and diaryl disulfides as the sulfur source . To complement this study, we were interested to discover whether our dual catalytic method could be used for the selective preparation of monothioarylated products (Scheme ).…”

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)–H and C(sp3)–H bonds

“…Very recently, Jiang and coworkers developed a convenient one-step regioselective synthesis of 3,6-dithiolated and 3,6-diselenylated carbazoles 14 via AgSbF 6 /K 2 S 2 O 8 -mediated double C–H functionalization of carbazoles 116 with diaryl disulfides 33 and diselenides 39 under air atmosphere (Scheme 39). 191 A range of carbazoles bearing N -alkyl, allyl, benzyl, aryl groups as well as unprotected carbazole were well tolerated. The protocol was also compatible with various electron-donating-group-bearing diaryl disulfides including the unprotected 4,4′-disulfanediyldiphenol but was totally ineffective for those bearing electron-withdrawing halogen substituents ( 14h ).…”