Regioselective C2 Sulfonylation of Indoles Mediated by Molecular Iodine

Abstract

A facile and general method for regioselective C2 sulfonylation reaction of indoles mediated by iodine is described. The 2-sulfonylated products were obtained up to 96% yield under mild reaction conditions (room temperature, 2 h).

Iodine/TBHP‐Promoted One‐Pot Deoxygenation and Direct 2‐Sulfonylation of Quinoline N‐Oxides with Sodium Sulfinates: Facile and Regioselective Synthesis of 2‐Sulfonylquinolines

“…These results imply that 2‐iodoquinoline N ‐oxide, 2‐iodoquinoline, nor quinoline is the intermediate generated in the iodination step of this reaction. We also questioned whether p ‐toluenesulfonyl iodide (TsI) could be the intermediate in this transformation because the reaction between a sodium sulfinate and molecular iodine can generate a relatively unstable sulfonyl iodide . Thus, p ‐toluenesulfonyl iodide (TsI) was prepared and utilized in the next experiment .…”

Direct sulfonylation of anilines mediated by visible light

“…Sulfonyl radicals are transient intermediates that undergo a range of reactions, including with alkenes 7 and alkynes. 8 However, examples of their reactivity with aromatic rings are scarce: 1 the groups of Deng and Kuhakarn have independently reported sulfonylation of indoles at the C-2 position using sodium sulfinate salts under oxidative conditions, 9 Li and coworkers have reported on hypervalent iodine-mediated sulfonylation of anilides with aryl sulfonyl chlorides, 10 and sulfonyl radicals have been implicated in transition-metal-catalyzed directed C–H sulfonylations. 11 Here we report on the development of a mild and robust sulfonylation protocol that is applicable to the late-stage functionalization of aniline containing drug-molecules.…”

The fast and efficient KI/H2O2 mediated 2-sulfonylation of indoles and N-methylpyrrole in water

“…In this case, the electronic nature of the substituent had no signicant inuence on the reactivity. Compared with the reported methods, [5][6][7][8][9] operational simplicity, short reaction time and good yield are the key advantages of this protocol.…”