We disclose herein our detailed investigation into the Barton copper-promoted C3-arylation of indoles using triarylbismuth bis(trifluoroacetates). The arylation of unsubstituted 1H-indole using Barton's conditions gave a low yield of the C3-arylated indole, along with small amounts of the product of double C2/C3-arylation and traces of the product of C2 arylation. On the contrary, the arylation of indoles blocked at the C2 position is highly efficient, affording the desired products of C3-arylation in good to excellent yields. The reaction operates under simple conditions, shows good substrate scope, excellent functional group compatibility, and allows the transfer of electron-neutral or deficient aryl groups. Computational studies propose a mechanism involving a trifluoroacetate-assisted C-H activation step.
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http://dx.doi.org/10.1002/cplu.202200465 | DOI Listing |
Org Lett
July 2023
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
A palladium-dihydroxyterphenylphosphine (DHTP) catalyst was successfully applied to the dearomative C3-arylation of tryptamine derivatives with aryl nonaflates. The intramolecular cyclization of the resulting 3,3-disubstituted indolenines afforded C3a-arylated pyrroloindolines in one pot. We postulate that the formation of complexes between the lithium salts of DHTP and the tryptamine derivative is the key to promoting selective arylation at the C3-position of the indole ring.
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May 2023
Département de chimie, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, H3C 3P8, Montréal, Québec, Canada.
Invited for this month's cover are the collaborating groups of Prof. Alexandre Gagnon at the Université du Québec à Montréal in Canada, and Dr. Claire McMullin at the University of Bath in the UK.
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August 2023
Département de chimie, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, H3C 3P8, Montréal, Québec, Canada.
We disclose herein our detailed investigation into the Barton copper-promoted C3-arylation of indoles using triarylbismuth bis(trifluoroacetates). The arylation of unsubstituted 1H-indole using Barton's conditions gave a low yield of the C3-arylated indole, along with small amounts of the product of double C2/C3-arylation and traces of the product of C2 arylation. On the contrary, the arylation of indoles blocked at the C2 position is highly efficient, affording the desired products of C3-arylation in good to excellent yields.
View Article and Find Full Text PDFOrg Biomol Chem
November 2022
School of Chemistry, University of Hyderabad, Hyderabad 500 046, Telangana, India.
Palladium-catalysed and base-dependent intra-molecular -substitution and cyclisation strategies involving -indolyl-substituted aryl-sulfonamides for the rapid construction of 2-aryl indole and indole-fused six-membered sultams are described. The Pd(OAc)/PhP/EtN combination delivers indolyl C2 arylated motifs C(2)-N bond cleavage followed by C-C bond formation. In sharp contrast to this, the Pd(OAc)/PhP/KCO combination induced intramolecular-Heck cross-coupling affords polycyclic sultams exclusively.
View Article and Find Full Text PDFChem Commun (Camb)
September 2021
Chinese Academy of Sciences Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, University of Chinese Academy of Sciences, Shanghai 201203, China.
C3-Arylation of indoles with aryl ketones is accomplished palladium-catalyzed ligand-promoted Ar-C(O) cleavage and subsequent C-H arylation of indole. Various (hetero)aryl ketones are compatible in this reaction, affording the corresponding 3-arylindoles in moderate to good yields. Further introduction of an indole moiety into the natural products desoxyestrone and evodiamine demonstrate the synthetic utility of this protocol.
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