The regio- and enantioselective (3+3) cycloaddition of nitrones with 2-indolylmethanols was accomplished by the cooperative catalysis of hexafluoroisopropanol (HFIP) and chiral phosphoric acid (CPA). Using this approach, a series of indole-fused six-membered heterocycles were synthesized in high yields (up to 98 %), with excellent enantioselectivities (up to 96 % ee) and exclusive regiospecificity. This approach enabled not only the first organocatalytic asymmetric (3+3) cycloaddition of nitrones but also the first C3-nucleophilic asymmetric (3+3) cycloaddition of 2-indolylmethanols. More importantly, theoretical calculations elucidated the role of the cocatalyst HFIP in helping CPA control the reactivity and enantioselectivity of the reaction, demonstrating a new mode of cooperative catalysis.
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http://dx.doi.org/10.1002/anie.202011267 | DOI Listing |
Chemistry
December 2024
Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, Kanpur, 208016, India.
Herein, we report a copper-catalyzed enantioselective formal (3+3) and (3+2) cycloaddition reaction of isatin-derived tertiary propargylic esters with N,N-dimethylbarbituric acid and 4-hydroxycoumarins, respectively. In this process, the tertiary propargylic ester serves as both C3- and C2-synthons, facilitating the synthesis of optically active spirooxindole-pyran and furan scaffolds featuring an all-carbon quaternary stereocenter. The reaction delivers these spirocyclic frameworks in good yields with high enantioselectivities.
View Article and Find Full Text PDFAntiinflamm Antiallergy Agents Med Chem
December 2024
Chemistry Department, Faculty of Science, The University of Jordan, Amman, 11942, Jordan.
Aims: This study aimed at the synthesis of several spiro[benzofuran-3,3'-pyrroles] derivatives by a three-component reaction conducted by mixing DMAD, N-bridgehead het-erocycles, and benzofuran-2,3-diones in dichloromethane at room temperature for 24 h. Moreover, in vitro evaluation of their cytotoxicity affinities against FMS-like tyrosine kinase 3 was carried out.
Objectives: The objective of this study was to use a one-pot, three-component reaction to synthesize a novel set of spiro[benzofuran-3,3'-pyrroles] derivatives.
Inorg Chem
December 2024
School of Materials Science and Chemical Engineering, Resource Recycling of Ningbo University - Ningbo Shuangneng Environmental Technology Co., Ltd., Ningbo University, Ningbo 315211, China.
The utilization of metal-organic frameworks (MOFs) as fluorescent sensors for the detection of environmental and chemical reagent pollutants as well as heterogeneous catalysis for CO conversion represents a crucial avenue of research with significant implications for the protection of human health. In this work, a Tb(III)-based three-dimensional metal-organic framework, [Tb(L)·4DMF] (Tb-MOF) (HL = 5'-(4-carboxy-3-hydroxyphenyl)-3,3″-dihydroxy-[1,1':3',1″-terphenyl]-4,4″-dicarboxylic acid), has been structurally conformed by single-crystal X-ray crystallography. It possesses a 1D rhombus channel along the [010] direction, featuring a pore size of 6.
View Article and Find Full Text PDFChemistry
December 2024
Albert-Ludwigs-Universität Freiburg, Institute of Organic Chemistry, Albertstraße 21, 79104, Freiburg, Germany.
A (3+3)-cycloaddition to afford 2-azabiyclo[3.1.1]heptanes was realized by reacting highly strained aryl bicyclo[1.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
School of Chemical Engineering, University of Science and Technology Liaoning, Qianshan Road 185, Anshan 114051, Liaoning, China.
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