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

Abstract

An efficient method for selective synthesis of mono‐ and bis‐sulfenylindoles was developed using a novel aerobic catalytic oxidation system KI/SeO2 for sulfenylation of indoles with disulfide/thiols. The selectivity was controlled by varying the amount of the catalytic system and sulfenylation agents. The reaction features easy operation, mild reaction conditions, good atom economy, gram‐scalability, and a metal‐free approach furnishing desired products in up to excellent yields.

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

“…The reactions were performed under milder conditions using KI as a non-toxic, inexpensive and readily available catalyst (Scheme 20b). 156 As shown in Scheme 20, a possible mechanism with three catalytic cycles was proposed. An electrophilic RSI species A is first generated from RSSR 33 and I 2 and it reacts with indole 76a to form In 2022, Nguyen and coworkers disclosed a TFA/DMSO-promoted C3-heteroarylthiolation of indoles 76 with heteroaryl thiols 43 via cross-dehydrogenative coupling (CDC) using DMSO as both a solvent and a mild oxidant (Scheme 21).…”

“…The reactions were performed under milder conditions using KI as a non-toxic, inexpensive and readily available catalyst (Scheme 20b). 156 As shown in Scheme 20, a possible mechanism with three catalytic cycles was proposed. An electrophilic RSI species A is first generated from RSSR 33 and I 2 and it reacts with indole 76a to form 3-thiolated indole 77 and HI (cycle A).…”

Selective Synthesis of 3‐Chalcogenylindoles via Silver‐Catalyzed Direct Chalcogenation of Indoles with Dichalcogenides

“…It was found that the presence of the signals in the 77 Se NMR at 462.85 ppm (2 a), at 383.75 ppm (2 a + AgNO 3 ; due to Ph 2 Se 2 Ag III A [31]) and at 209.92 ppm (3 a), All the spectral data of compounds 2 a, 2 a + AgNO 3 are in agreement with those from literature. [28] Characterization data of products 3-(Phenylselanyl)-1H-indole (4 a); [13] 95 % yield (0.2202 g) as a white solid; mp 134-137 °C; 1 H NMR (CDCl 3 , 400 MHz, ppm) δ 8.46 (br, 1H), 7.67 (d, J = 7.9 Hz, 1H), 7.52-7.46 (m, 2H), 7.32-7.25 (m, 3H), 7.23-7.11 (m, 4H). 13 C NMR (CDCl 3 , 100 MHz, ppm) δ 136.4, 133.8, 131.2, 130.0, 129.0, 128.8, 128.7, 125.6, 123.0, 120.9, 120.4, 111.4, 98.3.…”

“…[14,[19][20][21] We have recently reported the chalcogenylation of indoles to synthesize mono-and bissulfenylindoles in moderate to excellent yields using a KI/SeO 2 catalytic system. [28] By focusing on this topic, this work is aimed to develop a new and efficient protocol for direct C(sp 2 )À H chalcogenylation of indoles at the C3-position under mild conditions, low-cost and atom economy with a wide substrate scope.…”

Recent Advances in Synthesis of 3-Sulfenylated Indoles

“…4). 2022 年 Saeeng 等 [13] 以碘化钾/氧化硒(KI/SeO 2 )作为催化氧化 体系, 高效地合成了系列吲哚-3-硫醚类化合物(Eq. 5), 该方法操作简单, 反应条件温和, 并且适用于克级合成.…”