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Chen SY, Chang R, Lin ZX, Lin CW, Shen LC, Sue ACH, Tseng MC, Chu JH. Palladium-Mediated C(sp 3)-H Bond Activation of N-Methyl- N-(pyridin-2-yl)benzamide: Direct Arylation/Alkylation and Mechanistic Investigation. J Org Chem 2023. [PMID: 37276376 DOI: 10.1021/acs.joc.3c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Herein, we present a facile synthetic methodology to produce a range of N-(CH2-aryl/alkyl)-substituted N-(pyridin-2-yl)benzamides via palladium-mediated C(sp3)-H bond activation. The N-methyl-N-(pyridin-2-yl)benzamide precursor was first reacted with palladium(II) acetate in a stoichiometric manner to obtain the key dinuclear palladacycle intermediates, whose structures were elucidated by mass spectrometric, NMR spectroscopic, and X-ray crystallographic studies in detail. The subsequent C(sp3)-H bond functionalizations on the N-methyl group of the starting substrate show facile productions of the corresponding N-(CH2-aryl/alkyl)-substituted N-(pyridin-2-yl)benzamides with good functional group tolerance. A plausible mechanism was proposed based on density functional theory calculations in conjunction with kinetic isotope effect experiments. Finally, the synthetic transformation from the prepared N-(CH2-aryl)-N-(pyridin-2-yl)benzamides through debenzoylation to N-(CH2-aryl)-2-aminopyridine was successfully demonstrated.
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Affiliation(s)
- Shih-Yun Chen
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, R.O.C
| | - Rong Chang
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhong-Xin Lin
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, R.O.C
| | - Chien-Wen Lin
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, R.O.C
| | - Li-Ching Shen
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, Hsinchu, Taiwan 300093, R.O.C
| | - Andrew C-H Sue
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Mei-Chun Tseng
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan 115201, R.O.C
| | - Jean-Ho Chu
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, R.O.C
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Theoretical Investigation of the Mechanism of Rh(III)-catalyzed Annulation of 2-Biphenylboronic Acid with Activated Alkene. Chem Res Chin Univ 2022. [DOI: 10.1007/s40242-022-2187-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Hsiao PY, Chang R, Sue ACH, Chu JH, Liao GW, Lee YH, Huang JY. Synthesis and Mechanistic Investigation of Bipyrazolo[1,5- a]pyridines via Palladium-Catalyzed Cross-Dehydrogenative Coupling of Pyrazolo[1,5- a]pyridines. J Org Chem 2022; 87:9851-9863. [PMID: 35844185 DOI: 10.1021/acs.joc.2c00895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of a range of 3,3'-bipyrazolo[1,5-a]pyridine derivatives via direct cross-dehydrogenative coupling of pyrazolo[1,5-a]pyridine precursors is herein presented. This simple and efficient methodology involving palladium(II)-catalyzed C-H bond activation showed good functional group tolerance and product yield (up to 94%). Through the mechanistic insights gained from both kinetic isotope effect experimental studies and density functional theory calculations, a plausible reaction mechanism was outlined. Furthermore, subsequent derivatizations of the resulting 7,7'-diaryl-3,3'-bipyrazolo[1,5-a]pyridines, executed by performing palladium-mediated ortho C-H bond activation followed by hypervalent iodine-induced chlorination, rendered this series of compounds more extended π-conjugation and twisted conformations. Our study on these bipyrazolo[1,5-a]pyridine-based luminogens provides new opportunities for tailor-made organic luminescent materials.
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Affiliation(s)
- Pu-Yen Hsiao
- Department of Applied Science, National Taitung University, Taitung 95092, Taiwan, R.O.C
| | - Rong Chang
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Andrew C-H Sue
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jean-Ho Chu
- Department of Applied Science, National Taitung University, Taitung 95092, Taiwan, R.O.C
| | - Guan-Wei Liao
- Department of Applied Science, National Taitung University, Taitung 95092, Taiwan, R.O.C
| | - Yi-Hsin Lee
- Department of Applied Science, National Taitung University, Taitung 95092, Taiwan, R.O.C
| | - Jui-Yang Huang
- Department of Applied Science, National Taitung University, Taitung 95092, Taiwan, R.O.C
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Reactions of Cyclopalladated Complexes with Boronic Acids. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.121114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Greco R, Tiburcio-Fortes E, Fernandez A, Marini C, Vidal-Moya A, Oliver-Meseguer J, Armentano D, Pardo E, Ferrando-Soria J, Leyva-Pérez A. MOF-stabilized perfluorinated palladium cages catalyze the additive-free aerobic oxidation of aliphatic alcohols to acids. Chemistry 2021; 28:e202103781. [PMID: 34929061 DOI: 10.1002/chem.202103781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Indexed: 11/08/2022]
Abstract
Extremely high electrophilic metal complexes, composed by a metal cation and very electron poor σ-donor ancillary ligands, are expected to be privileged catalysts for oxidation reactions in organic chemistry. However, their low lifetime prevents any use in catalysis. Here we show the synthesis of fluorinated pyridine-Pd 2+ coordinate cages within the channels of an anionic tridimensional metal organic framework (MOF), and their use as efficient metal catalysts for the aerobic oxidation of aliphatic alcohols to carboxylic acids without any additive. Mechanistic studies strongly support that the MOF-stabilized coordination cage with perfluorinated ligands unleashes the full electrophilic potential of Pd 2+ to dehydrogenate primary alcohols, without any base, and also to activate O 2 for the radical oxidation to the aldehyde intermediate. This study opens the door to design catalytic perfluorinated complexes for challenging organic transformations, where an extremely high electrophilic metal site is required.
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Affiliation(s)
- Rossella Greco
- CSIC: Consejo Superior de Investigaciones Cientificas, ITQ, SPAIN
| | | | | | | | | | | | | | | | | | - Antonio Leyva-Pérez
- CSIC, Instituto de Tecnologia Quimica, Avda. de los Naranjos S/N, 46022, Valencia, SPAIN
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Hsiao PY, Chu JH. Novel bipyrazolo[1,5- a]pyridine luminogens with aggregation-induced emission enhancement properties. Chem Commun (Camb) 2021; 57:12281-12284. [PMID: 34730135 DOI: 10.1039/d1cc05371j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A novel 3,3'-bipyrazolo[1,5-a]pyridine molecular scaffold was obtained as a product of serendipity. Both photophysical characterisations and HOMO-LUMO theoretical calculations indicate its potential as a promising fluorophore with notable intramolecular charge transfer. Nonetheless, the emission properties of this compound suffer from the typical aggregation-caused quenching effect. To overcome this situation, we introduced additional diaryl groups onto the skeleton and synthesised a series of 7,7'-diaryl-3,3'-bipyrazolo[1,5-a]pyridines via palladium-catalysed intermolecular C-H/C-H bond cross-coupling reaction in 35-62% yields. This series of tailor-made luminogens with twisted π-structures display aggregation-induced emission enhancement properties.
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Affiliation(s)
- Pu-Yen Hsiao
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, Taiwan.
| | - Jean-Ho Chu
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95092, Taiwan.
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