The activation of C⁻H bonds through catalytic reactions using transition metals is an important challenge in organic chemistry in which the intermediates are related to those produced in the classical cross-coupling reactions. As part of our research program devoted to the development of metal-catalyzed reactions using indium organometallics, a protocol for the C⁻H activation and C⁻C coupling of 2-arylpyridines with triorganoindium reagents under Rh(I) catalysis is reported. Under the optimized conditions, we found that Me₃In and Ar₃In reagents reacted with 2-arylpyridines and related compounds in the presence of Rh(PPh₃)₃Cl, in PhCl/THF (9:1), at 120 °C for 48 h, to afford the -coupling products in moderate to good yields. The nitrogen atom in the pyridine ring acts as a directing group to assist the functionalization at the position of the aryl group forming a new C⁻C bond at this position.
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http://dx.doi.org/10.3390/molecules23071582 | DOI Listing |
J Org Chem
January 2022
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States.
A versatile and efficient method to prepare borylated arenes furnished with alkyl, alkenyl, alkynyl, aryl, and heteroaryl functional groups is developed by merging Ir-catalyzed C-H borylations (CHB) with a chemoselective palladium-catalyzed cross-coupling of triorganoindium reagents (Sarandeses-Sestelo coupling) with aryl halides bearing a boronic ester substituent. Using triorganoindium cross-coupling reactions to introduce unsaturated moieties enables the synthesis of borylated arenes that would be difficult to access through the direct application of the CHB methodology. The sequential double catalyzed procedure can be also performed in one vessel.
View Article and Find Full Text PDFJ Org Chem
July 2021
Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain.
The indium(III)-catalyzed cascade cycloisomerization reaction of 1,5-enynes with pendant aryl nucleophiles is reported. The reaction proceeds in cascade under mild reaction conditions, using InI (5 mol %) as a catalyst with a range of 1,5-enynes furnished with aryl groups (phenyl and phenol) at alkene ( and Z isomers) and with terminal and internal alkynes. Using 1-bromo-1,5-enynes, a one-pot sequential indium-catalyzed cycloisomerization and palladium-catalyzed cross-coupling with triorganoindium reagents were developed.
View Article and Find Full Text PDFJ Org Chem
August 2019
Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química , Universidade da Coruña , E-15071 A Coruña , Spain.
Triorganoindium reagents (RIn) react with tetrahydroisoquinolines (THIQs) in the presence of PhCBF as an oxidant to afford 1-substituted THIQs. The reaction proceeds in good yields at rt using 50 mol % RIn with a variety of organic groups. H NMR studies show the generation of an iminium ion intermediate, supporting a two-step mechanism based on THIQ oxidation and RIn nucleophilic addition.
View Article and Find Full Text PDFJ Org Chem
July 2019
Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química , Universidade da Coruña , E-15071 A Coruña , Spain.
A series of donor-acceptor-acceptor (D-A-A) and donor-acceptor-donor (D-A-D) systems based on a pyrimidine π-spacer with various substituents at the C-2 position has been successfully prepared. The synthesis involved site-selective palladium cross-coupling reactions of chloropyrimidines with triorganoindium reagents and proceed in good yields and with atom economy. 4-(,-Diphenylamino)phenyl was chosen as the donor group and thien-2-yl dicyanovinylene as the acceptor one.
View Article and Find Full Text PDFMolecules
June 2018
Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain.
The activation of C⁻H bonds through catalytic reactions using transition metals is an important challenge in organic chemistry in which the intermediates are related to those produced in the classical cross-coupling reactions. As part of our research program devoted to the development of metal-catalyzed reactions using indium organometallics, a protocol for the C⁻H activation and C⁻C coupling of 2-arylpyridines with triorganoindium reagents under Rh(I) catalysis is reported. Under the optimized conditions, we found that Me₃In and Ar₃In reagents reacted with 2-arylpyridines and related compounds in the presence of Rh(PPh₃)₃Cl, in PhCl/THF (9:1), at 120 °C for 48 h, to afford the -coupling products in moderate to good yields.
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