1
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Khatua M, Goswami B, Devi A, Kamal, Hans S, Samanta S. A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines. Inorg Chem 2024; 63:9786-9800. [PMID: 38739882 DOI: 10.1021/acs.inorgchem.4c00086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 and 2 were synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 and H2L2, respectively. The ligands and complexes were fully characterized by various physicochemical and spectroscopic characterization techniques. Finally, the identity of the complexes 1 and 2 was confirmed by single crystal X-ray structure determination. The phosphine ligand containing complex 1 was converted to the phosphine oxide ligand containing complex 2 in air in acetonitrile solution. Both complexes 1 and 2 were investigated as precatalysts for alcohol dehydrogenation-triggered synthesis of imines in air. The phosphine-oxide complex 2 was more efficient than the phosphine complex 1. A wide array of alcohols and amines were successfully reacted in a mild condition to result in imines in good to excellent yields. Precatalyst 2 was also highly efficient for the synthesis of varieties of quinolines in air. As H2L2 in 2 has side arms that can be deprotonated, we investigated complex 2 for its base (KOtBu) promoted deprotonation events by various spectroscopic studies and DFT calculations. These studies have shown that mono deprotonation of the amine side arm attached to the pyridine is quite feasible, and deprotonation of complex 2 leads to a dearomatized pyridyl ring containing complex 2a. The mechanistic investigations of the catalytic reaction, by a combination of experimental and computational studies, have suggested that the dearomatized complex, 2a acted as an active catalyst. The reaction proceeded through the hydride transfer pathway. The activation barrier of this step was calculated to be 26.5 kcal/mol, which is quite consistent with the experimental reaction temperature under aerobic conditions. Although various pincer-like complexes are explored for such reactions, phosphine oxide ligand-containing complexes are still unexplored.
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Affiliation(s)
- Manas Khatua
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West Bengal 741246, India
| | - Bappaditya Goswami
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West Bengal 741246, India
| | - Ambika Devi
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India
| | - Kamal
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India
| | - Shivali Hans
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India
| | - Subhas Samanta
- Department of Chemistry, Indian Institute of Technology (IIT) Jammu, Jagti, Jammu, Jammu and Kashmir 181221, India
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2
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Gholap SS, Dakhil AA, Chakraborty P, Dighe S, Rahman MM, Dutta I, Hengne A, Huang KW. Efficient and chemoselective imine synthesis catalyzed by a well-defined PN 3-manganese(II) pincer system. Chem Commun (Camb) 2024; 60:2617-2620. [PMID: 38351877 DOI: 10.1039/d3cc05892a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
The highly efficient reductive amination of aldehydes with ammonia (NH3) and hydrogen (H2) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN3-manganese(II) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH3 as a nitrogen source under H2 in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes.
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Affiliation(s)
- Sandeep Suryabhan Gholap
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Abdullah Al Dakhil
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
- Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University, Riyadh 11432-5701, Saudi Arabia
| | - Priyanka Chakraborty
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Shashikant Dighe
- Agency for Science, Technology and Research, Institute of Materials Research and Engineering and Institute of Sustainability for Chemicals, Energy and Environment, Singapore
| | - Mohammad Misbahur Rahman
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Indranil Dutta
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Amol Hengne
- Agency for Science, Technology and Research, Institute of Materials Research and Engineering and Institute of Sustainability for Chemicals, Energy and Environment, Singapore
| | - Kuo-Wei Huang
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
- Agency for Science, Technology and Research, Institute of Materials Research and Engineering and Institute of Sustainability for Chemicals, Energy and Environment, Singapore
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3
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Paramonova P, Eliseev I, Dar'in D, Bakulina O. Imines with rare α-heteroatom substituted amine components generated in situ via the Staudinger/aza-Wittig tandem reaction and their application in multicomponent reactions. Org Biomol Chem 2024; 22:1733-1744. [PMID: 38323438 DOI: 10.1039/d3ob01832f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
A series of structurally diverse α-heteroatom substituted methyl azides (XCH2N3, where X = phthalimidoyl, benzotriazolyl, arylsulfanyl, aryloxy, alkoxy) have been prepared and evaluated for the in situ generation of imines via the Staudinger/aza-Wittig tandem reaction with aldehydes and triphenylphosphine. The obtained imines were successfully introduced into four types of multicomponent reactions: the Staudinger β-lactam synthesis with diazo carbonyl compounds, the Castagnoli-Cushman reaction with cyclic anhydrides, and the Ugi and azido-Ugi reactions with isocyanides and carboxylic acids or TMS-azides. These transformations allowed the preparation of four-to-seven-membered lactams, acyclic bisamides and 5-(aminomethyl)-1-alkyltetrazoles with a complex and previously poorly accessible periphery. Moreover, it was demonstrated that phthalimide derivatives can be deprotected to afford medicinally relevant N-aminomethyl lactams.
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Affiliation(s)
- Polina Paramonova
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russia.
| | - Ilia Eliseev
- Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Dmitry Dar'in
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russia.
- Saint Petersburg Research Institute of Phthisiopulmonology, Saint Petersburg, 191036, Russia
| | - Olga Bakulina
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russia.
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4
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Singh RK, Yadav D, Misra S, Singh AK. Role of ancillary ligands in selectivity towards acceptorless dehydrogenation versus dehydrogenative coupling of alcohols and amines catalyzed by cationic ruthenium(II)-CNC pincer complexes. Dalton Trans 2023; 52:15878-15895. [PMID: 37830304 DOI: 10.1039/d3dt03149g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
An unexpected reversal in catalytic activity for acceptorless dehydrogenative coupling compared to acceptorless alcohol dehydrogenation has been observed using a series of cationic Ru(II)-CNC pincer complexes with different ancillary ligands. In continuation of our study of cationic Ru(II)-CNC pincer complexes 1a-6a, new complexes with bulky N-wingtips [Ru(CNCiPr)(CO)(PPh3)Br]PF6 (1b), [Ru(CNCCy)(CO)(PPh3)Cl]PF6 (1c), [Ru(CNCCy)(CO)(PPh3)H]PF6 (2c), [Ru(CNCiPr)(PPh3)2Cl]PF6 (3b), [Ru(CNCCy)(PPh3)2Cl]PF6 (3c), [Ru(CNCiPr)(PPh3)2H]PF6 (4b), [Ru(CNCCy)(PPh3)2H]PF6 (4c), [Ru(CNCiPr)(DMSO)2Cl]PF6 (6b), and [Ru(CNCCy)(DMSO)2Cl]PF6 (6c) [CNCR = 2,6-bis(1-alkylimidazol-2-ylidene)-pyridine] have been synthesized and the catalytic activities of the new complexes have been compared with their N-methyl analogues for transfer hydrogenation of cyclohexanone and acceptorless dehydrogenation of benzyl alcohol. Furthermore, all complexes have been utilized as catalysts in the dehydrogenative coupling reaction of benzyl alcohol with amines. While the catalytic activities of the new complexes for transfer hydrogenation and acceptorless alcohol dehydrogenation were found to be in line with the previously observed trend based on the ancillary ligands (CO > COD > DMSO > PPh3), for the acceptorless dehydrogenative coupling reaction, complexes containing PPh3 and DMSO ligands performed better compared to complexes containing CO and COD ligands. Based on NMR and mass investigation of catalytic reactions, a plausible mechanism has been suggested to explain the difference in catalytic activity and its reversal during the dehydrogenative coupling reaction. Furthermore, the substrate scope for the dehydrogenative coupling reaction of benzyl alcohol with a wide range of amines has been explored, including synthesizing some pharmaceutically important imines. All new complexes have been characterized by various spectroscopic techniques, and the structures of 4b and 6b have been confirmed by the single-crystal X-ray diffraction technique.
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Affiliation(s)
- Rahul Kumar Singh
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
| | - Dibya Yadav
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
| | - Shilpi Misra
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
- Centre for Scientific and Applied Research, IPS Academy, Indore 452012, India
| | - Amrendra K Singh
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
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5
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Yadav D, Singh RK, Misra S, Singh AK. Ancillary Ligand Effects and Microwave‐Assisted Enhancement on the Catalytic Performance of Cationic Ruthenium (II)‐CNC Pincer Complexes for Acceptorless Alcohol Dehydrogenation. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dibya Yadav
- Department of Chemistry Indian Institute of Technology Indore Indore India
| | - Rahul Kumar Singh
- Department of Chemistry Indian Institute of Technology Indore Indore India
| | - Shilpi Misra
- Department of Chemistry Indian Institute of Technology Indore Indore India
| | - Amrendra K. Singh
- Department of Chemistry Indian Institute of Technology Indore Indore India
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6
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Badhani G, Joshi A, Adimurthy S. Ionic‐Liquid‐Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C−N, C−S, and C−C Bond Formation. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Gaurav Badhani
- Academy of Scientific & Innovative Research, Ghaziabad CSIR-Central Salt & Marine Chemicals Research Institute G. B. Marg Bhavnagar 364 002 Gujarat India
| | - Abhisek Joshi
- Academy of Scientific & Innovative Research, Ghaziabad CSIR-Central Salt & Marine Chemicals Research Institute G. B. Marg Bhavnagar 364 002 Gujarat India
| | - Subbarayappa Adimurthy
- Academy of Scientific & Innovative Research, Ghaziabad CSIR-Central Salt & Marine Chemicals Research Institute G. B. Marg Bhavnagar 364 002 Gujarat India
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7
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Borthakur I, Maji M, Joshi A, Kundu S. Reductive Alkylation of Azides and Nitroarenes with Alcohols: A Selective Route to Mono- and Dialkylated Amines. J Org Chem 2021; 87:628-643. [PMID: 34898200 DOI: 10.1021/acs.joc.1c02625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we demonstrated an efficient protocol for reductive alkylation of azides/nitro compounds via a borrowing hydrogen (BH) method. By following this protocol, selective mono- and dialkylated amines were obtained under mild and solvent-free conditions. A series of control experiments and deuterium-labeling experiments were performed to understand this catalytic process. Mechanistic studies suggested that the Ir(III)-H was the active intermediate in this reaction. KIE study revealed that the breaking of the C-H bond of alcohol might be the rate-limiting step. Notably, this solvent-free strategy disclosed a high TON of around 5600. Based on kinetic studies and control experiments, a metal-ligand cooperative mechanism was proposed.
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Affiliation(s)
- Ishani Borthakur
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh (U.P.), India
| | - Milan Maji
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh (U.P.), India
| | - Abhisek Joshi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh (U.P.), India
| | - Sabuj Kundu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh (U.P.), India
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8
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Gholap SS, Dakhil AA, Chakraborty P, Li H, Dutta I, Das PK, Huang KW. Efficient and chemoselective hydrogenation of aldehydes catalyzed by well-defined PN 3-pincer manganese(II) catalyst precursors: an application in furfural conversion. Chem Commun (Camb) 2021; 57:11815-11818. [PMID: 34693946 DOI: 10.1039/d1cc04808b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Well-defined and air-stable PN3-pincer manganese(II) complexes were synthesized and used for the hydrogenation of aldehydes into alcohols under mild conditions using MeOH as a solvent. This protocol is applicable for a wide range of aldehydes containing various functional groups. Importantly, α,β-unsaturated aldehydes, including ynals, are hydrogenated with the CC double bond/CC triple bond intact. Our methodology was demonstrated for the conversion of biomass derived feedstocks such as furfural and 5-formylfurfural to furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol respectively.
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Affiliation(s)
- Sandeep Suryabhan Gholap
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Abdullah Al Dakhil
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia. .,Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University, Riyadh 11432-5701, Saudi Arabia
| | - Priyanka Chakraborty
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Huaifeng Li
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Indranil Dutta
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Pradip K Das
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Kuo-Wei Huang
- KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
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