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A Bi(III)-catalyzed synthetic strategy for regioselective construction of C-N bonds via a simple Michael addition reaction is reported. A wide range of tautomerizable heterocycles such as benzoxazolones, benzothiazolones, benzimidazolinones, indolinones, and 2-pyridones along with α,β-unsaturated carbonyls (ketones and esters) are employed to create a library of corresponding -alkylated derivatives exclusively. High regioselectivity, high atom economy, and the participation of a range of tautomerizable heterocycles highlight the uniqueness and generality of the developed methodology.
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http://dx.doi.org/10.1021/acs.joc.4c01169 | DOI Listing |
J Org Chem
September 2024
Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, West Bengal, India.
A Bi(III)-catalyzed synthetic strategy for regioselective construction of C-N bonds via a simple Michael addition reaction is reported. A wide range of tautomerizable heterocycles such as benzoxazolones, benzothiazolones, benzimidazolinones, indolinones, and 2-pyridones along with α,β-unsaturated carbonyls (ketones and esters) are employed to create a library of corresponding -alkylated derivatives exclusively. High regioselectivity, high atom economy, and the participation of a range of tautomerizable heterocycles highlight the uniqueness and generality of the developed methodology.
View Article and Find Full Text PDFOrg Biomol Chem
April 2022
Department of Chemistry, University of Calcutta 92, A. P. C. Road, Kolkata-700009, India.
Herein, we report a practical and simple mono- and di-C(sp)-O cross-coupling of tautomerizable N-heterocycles (dihydrophthalazine-1,4-diones, pyridone, quinoxalinone and pyrimidinone) with ketones, β-dicarbonyl compounds and nitroalkane, leading to substituted imidate derivatives under visible-light conditions. The combination of rose bengal as the photocatalyst and TBHP enables sustainable reaction conditions, operational simplicity, and high chemo- and regioselectivity with exceptional yields (up to 94%), good functional group tolerance and substrate generality. In the case of unsymmetrical ketones, the less substituted end is functionalized selectively.
View Article and Find Full Text PDFMolecules
March 2018
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, C.P. 09340, Del. Iztapalapa, Ciudad de México, Mexico.
We describe the one-pot synthesis of twenty polyheterocyclic pyrrolo[3,4-]pyridin-5-ones a cascade process (Ugi-3CR/aza Diels-Alder/-acylation/aromatization) in 20 to 95% overall yields, as well as four pharmacologically promising analogues an improved cascade process (Ugi-3CR/aza Diels-Alder/-acylation/aromatization/S2): two piperazine-linked pyrrolo[3,4-]pyridin-5-ones in 33 and 34%, and a couple of Falipamil aza-analogues in 30 and 35% overall yields. It is worth highlighting the good substrate scope found, because final products are furnished with alkyl, aryl, and heterocyclic substituents. The use of chain-ring tautomerizable isocyanides (as key reagents for the Ugi-type three component reaction) allowed for a rapid and efficient assembly of the polysubstituted oxindoles, which were used in situ toward the complex products, conferring features like robustness, sustainability, and the one-pot approach to this synthetic methodology.
View Article and Find Full Text PDFOrg Biomol Chem
July 2017
College of Chemical Engineering, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China.
A method for the allylic amidation of tautomerizable heterocycles was developed by a palladium catalyzed allylation reaction with 100% atom economy. A series of structurally diverse N-allylic substituted heterocycles can be synthesized in good yields with high chemo-, regio-, and stereoselectivities under mild conditions.
View Article and Find Full Text PDFOrg Lett
April 2012
Laboratory for Organic & Microwave-Assisted Chemistry, Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium.
The direct cross-coupling of tautomerizable heterocycles with various unfunctionalized heteroarenes has been achieved through PyBroP-mediated and Pd/Cu-catalyzed sequential C-OH/C-H activation. The methodology allows a facile entry into novel diazine-azole biheterocyclic frameworks. Moreover, an unprecedented Pd-catalyzed phosphonium homocoupling of tautomerizable heterocycles was also developed to afford a direct synthetic route to symmetrical 1,2-, 1,3-, and 1,4-bidiazine units.
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