InBr3-catalyzed sulfonation of indoles: a facile synthesis of 3-sulfonyl indoles

Yadav, J. S.; Reddy, B. V. Subba; Krishna, A. D.; Swamy, T.

doi:10.1016/s0040-4039(03)01507-7

Cited by 45 publications

(13 citation statements)

References 15 publications

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“…Mixing indoles 6 a and 6 b with tosyl chloride in the presence of AuBr 3 or InBr 3 did not give the corresponding sulfonylindoles 2 , 3 , and 4 [Eq. (8)] 3. Accordingly, it is unlikely that electrophilic substitution of the indole with tosyl halides occurs under these reaction conditions. …”

Section: Aubr3‐catalyzed Cyclization Of 1 B–o[a]mentioning

confidence: 98%

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

et al. 2007

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Section: Aubr3‐catalyzed Cyclization Of 1 B–o[a]mentioning

confidence: 98%

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

et al. 2007

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Section: Aubr3‐catalyzed Cyclization Of 1 B–o[a]mentioning

confidence: 98%

“…Although Yadav et al. recently reported that the indium‐catalyzed reaction of indoles with sulfonyl chlorides leads to 3‐sulfonylindoles,3, 4 the development of an efficient and robust method to synthesize sulfonylindoles, which could lead to the discovery of new bioactive compounds,5 is still a challenge in organic synthesis.…”

Section: Aubr3‐catalyzed Cyclization Of 1 B–o[a]mentioning

confidence: 99%

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

et al. 2007

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Aufeinander folgende C‐N‐ und C‐S‐Verküpfungen durch intramolekulare Aminosulfonylierung: Die goldkatalysierte Reaktion der 2‐Alkinyl‐N‐sulfonylaniline 1 (R1=H) ergibt 3‐Sulfonylindole 2 in guten bis hohen Ausbeuten, die Umsetzung von 2‐Alkinyl‐6‐methoxy‐N‐sulfonylanilinen 1 (R1=MeO) in Gegenwart von InBr3 führt hingegen zu 6‐Sulfonylindolen 3 als Hauptprodukten (siehe Schema).

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“…1b Recently, Yadav et al. reported the indium‐catalyzed reaction of indoles with sulfonyl chlorides to produce 3‐sulfonylindoles 3. We repeated their reaction, but so far have not been able to obtain 3‐sulfonylindoles in good yields 4.…”

Section: Introductionmentioning

confidence: 97%

Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines by the Use of Lewis Acidic Transition‐Metal Catalysts

Nakamura

Yamagishi

Song

et al. 2008

Chemistry An Asian Journal

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Gold-catalyzed reactions of ortho-alkynyl-N-sulfonylanilines produced the corresponding 3-sulfonylindoles in good to high yields. For example, the reaction of N-mesyl-N-methyl-2-(1-pentynyl)aniline, N-mesyl-N-methyl-2-(phenylethynyl)-aniline, and 2-ethynyl-N-mesyl-N-methylaniline in the presence of 10 mol % of AuBr3 in toluene at 80 degrees C gave 3-mesyl-1-methyl-2-propylindole, 3-mesyl-1-methyl-2-phenylindole, and 3-mesyl-1-methylindole in 95, 92, and 71% yield, respectively. Furthermore, we found that the reactions of 2-alkynyl-6-methoxy-N-sulfonyl-anilines in the presence of indium catalyst (InBr3) afforded the corresponding 6-sulfonylindoles as the major product in good yields. For example, the reaction of 6-methoxy-N-methyl-2-(1-pentynyl)-N-tosylaniline in the presence of 5 mol % of InBr3 in toluene at 80 degrees C gave an 87:13 mixture of 7-methoxy-1-methyl-2-propyl-6-tosylindole and 7-methoxy-1-methyl-2-propyl-3-tosylindole in 95% yield. Most probably, the gold-catalyzed reactions of ortho-alkynyl-N-sulfonylanilines proceed through a [1,3] sulfonyl migration, whereas the indium-catalyzed cyclizations of 2-alkynyl-6-methoxy-N-sulfonylanilines, which produce 6-sulfonylindoles, proceed by an unprecedented [1,7] sulfonyl migration.

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InBr3-catalyzed sulfonation of indoles: a facile synthesis of 3-sulfonyl indoles

Cited by 45 publications

References 15 publications

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

Gold‐ and Indium‐Catalyzed Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines

Synthesis of 3‐ and 6‐Sulfonylindoles from ortho‐Alkynyl‐N‐sulfonylanilines by the Use of Lewis Acidic Transition‐Metal Catalysts

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