The synthesis of imidazo[1,5-a]pyridines through denitrogenative transannulation of pyridotriazoles with nitriles using BF·EtO as catalyst has been described. The combination of solvents (dichlorobenzene-dichloroethane) plays a crucial role in achieving quantitative yields of desired products under metal-free conditions.
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http://dx.doi.org/10.1021/acs.joc.6b01742 | DOI Listing |
Angew Chem Int Ed Engl
June 2024
College of Chemistry and Chemical Engineering, Qingdao University, Ningxia Road 308#, Qingdao, 266071, China.
Nickel-catalyzed transannulation reactions triggered by the extrusion of small gaseous molecules have emerged as a powerful strategy for the efficient construction of heterocyclic compounds. However, their use in asymmetric synthesis remains challenging because of the difficulty in controlling stereo- and regioselectivity. Herein, we report the first nickel-catalyzed asymmetric synthesis of N-N atropisomers by the denitrogenative transannulation of benzotriazones with alkynes.
View Article and Find Full Text PDFOrg Lett
November 2023
Department of Chemistry, Tamkang University, New Taipei City 251301, Taiwan, Republic of China.
Herein, we report a nickel-catalyzed intramolecular denitrogenative dual annulation reaction of aryl nitrile-containing 1,2,3-benzotriazine-4(3)-ones to synthesize polycyclic pyrroloquinazolinones with a tolerance of a wide diversity of substituents. This catalytic reaction is the first denitrogenative transannulation of 1,2,3-benzotriazine-4(3)-one with nitrile, which can be applied as the critical step to synthesize luotonin A with a high step economy.
View Article and Find Full Text PDFChem Asian J
November 2023
Department of Chemistry, SRM University AP, Amaravati, Andhra Pradesh, 522502, India.
A palladium-catalyzed denitrogenative transannulation strategy to access various 3-substituted isocoumarin-1-imine frameworks using 1,2,3-benzotriazin-4(3H)-ones and terminal alkynes is described. The reaction is highly regioselective and tolerates a wide range of functional groups. The reaction is believed to proceed via a five-membered palladacycle intermediate extruding environmentally benign molecular nitrogen as a by-product.
View Article and Find Full Text PDFOrg Lett
December 2022
Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, China.
An expedient synthesis of benzo[][1,2]dithiol-3-ones via metal-free denitrogenative transannulation of benzotriazinones is developed, which represents the first example of acid-mediated heteroannulation of benzotriazinones. This newly discovered reactivity of benzotriazinones enables the streamline synthesis of diverse benzo[][1,2]dithiol-3-ones in decent yields by using sodium sulfide as the sulfur source under simple reaction conditions.
View Article and Find Full Text PDFOrg Biomol Chem
September 2022
School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, P. R. China.
Nitrogen-based heterocycles are an important class of structural scaffolds distributed in biologically active natural products, medicinal chemistry, and agrochemicals. Hence, there is increasing interest in the development of novel synthetic strategies for the construction of these privileged structural motifs. Recently, 3-aminoindazoles have emerged as versatile synthons participating in a variety of condensation annulation, denitrogenative transannulation and rearrangement ring expansion reactions, which provide efficient synthetic routes for the formation of nitrogen heterocycles.
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