Copper(I) Iodide Catalyzed 3-Sulfenylation of Indoles with Unsymmetric Benzothiazolyl-Containing Disulfides at Room Temperature

Abstract

A highly efficient protocol for the synthesis of 3-sulfenylindoles in moderate to excellent yields via the reaction of indoles with unsymmetric benzothiazolyl-containing disulfides is described. Copper(I) iodide is used as the catalyst and the reactions take place at room temperature. The by-product, 2-mercaptobenzothiazole, can be easily recovered and reused.

Base-mediated chalcogenoaminative annulation of 2-alkynylanilines for direct access to 3-sulfenyl/selenyl-1H-indoles

“…Based on the control experiments and relevant studies in the past, 11,12 plausible pathways for this interesting chalcogenoaminative annulation between 1a and 2a are shown in Scheme 4. As shown in path A, initially, in the presence of a base, annulation occurs via an intramolecular nucleophilic attack of an NH 2 group on the triple bond of 1a to generate anion species I .…”

Sulfoximines as S-Aryl Surrogates: A Photocatalytic Rapid, Metal-Free, Mild Protocol to Access 3-Arylsulfenyl Indoles

“…Generally, the construction of 3-sulfenylindoles follow two strategies. It can be synthesized by either cyclization, followed by sulfenylation reactions of oethenylaryl isocyanides, 9 2-alkylanilines, 10 phenylhydrazine hydrochloride, 11 2-(gem-dibromovinyl) anilines, 12 or via direct sulfenylation (C-S coupling) of indoles employing a variety of sulfenylating reagents, such as thiols, 8, 13-15, 16, 17 disulfides, 18,19,[20][21][22][23] arylsulfonyl chlorides, 24, 25 arylsulfonium salts, 26,27 sulfinic acids, 28,29 sulfonyl hydrazides, 30 hydroxy sulfonamides, 31 arylsulfenyl halides, 32 and aryl-N-thioimides. 33,34 (Scheme 2).…”

“…33,34 (Scheme 2). However, most of these stated reactions have used hazardous metal catalysts like VO(acac)2, 14 FeCl3, 13 FeF3, 23 MgBr2, 33 PdCl2, 35 CuI, 18 and CeCl3. 34 Though oxygen (green reagent) is used as oxidant in few reported protocols, 8c, 14 but many of these reactions need harsh environments like high temperature, 17,22,31 long reaction time, 20,22,23,27,31 extra additives, 28,31 oxidants, 16,21,26,27 and inert reaction conditions.…”

“…33,34 (Scheme 2). However, most of these reactions require hazardous metal catalysts such as VO(acac) 2 , 14 FeCl 3 , 13 FeF 3 , 23 MgBr 2 , 33 PdCl 2 , 35 CuI, 18 or CeCl 3 . 34 Although oxygen (a green reagent) is used as the oxidant in a few reported protocols, 8c,14 many of these reactions require harsh environments such as high tempera-…”