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Karapanou MI, Malliotaki D, Stratakis M. Au nanoparticle-catalyzed double hydrosilylation of nitriles by diethylsilane. Org Biomol Chem 2024; 22:5346-5352. [PMID: 38861320 DOI: 10.1039/d4ob00534a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
We present the first example of Au-catalyzed reduction of nitriles into primary amines. In contrast to monohydrosilanes which are completely unreactive, diethylsilane (a dihydrosilane) is capable of reducing aryl or alkyl nitriles into primary amines under catalysis by Au nanoparticles supported on TiO2, via a smooth double hydrosilylation pathway. The produced labile N-disilylamines are readily deprotected by HCl in Et2O to form the hydrochloric salts of the corresponding amines in very good to excellent yields. The catalyst is recyclable and reusable at least in 5 consecutive runs.
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Affiliation(s)
| | - Dimitra Malliotaki
- Department of Chemistry, University of Crete, Voutes, 71003, Heraklion, Greece.
| | - Manolis Stratakis
- Department of Chemistry, University of Crete, Voutes, 71003, Heraklion, Greece.
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2
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Kumar R, Meher RK, Karmakar H, Panda TK. Hydrosilylation of nitriles and tertiary amides using a zinc precursor. Org Biomol Chem 2024; 22:3053-3058. [PMID: 38545870 DOI: 10.1039/d4ob00161c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
We report a competent and selective hydrosilylation of nitriles and tertiary amides catalyzed by the readily available zinc bis(hexamethyldisilazide) under solvent-free and mild conditions, making it a sustainable and desirable alternative to existing methods. Both protocols afforded high conversion, superior selectivity, and a broad substrate scope, from electron-withdrawing to electron-donating and heterocyclic substitutions.
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Affiliation(s)
- Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Rohan Kumar Meher
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Himadri Karmakar
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
| | - Tarun K Panda
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
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3
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Shirai T, Migitera Y, Nakajima R, Kumamoto T. Palladium-Catalyzed Reductive Heck Hydroarylation of Unactivated Alkenes Using Hydrosilane at Room Temperature. J Org Chem 2024; 89:2787-2793. [PMID: 38301250 PMCID: PMC10877589 DOI: 10.1021/acs.joc.3c02488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/28/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024]
Abstract
The reductive Heck hydroarylation of unactivated alkenes has emerged as an essential reaction for regioselective hydroarylation. Herein, we report a palladium-catalyzed reductive Heck hydroarylation of unactivated alkenes under mild conditions with enhanced functional group tolerance using hydrosilane as the reducing reagent. Under the optimal conditions, the alkylarene yields increased, resulting in minimal undesired products. Mechanistic studies using deuterated reagents indicated the involvement of two competing catalytic cycles.
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Affiliation(s)
- Takahiro Shirai
- Graduate
School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yusuke Migitera
- School
of Pharmaceutical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Ryo Nakajima
- Graduate
School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Takuya Kumamoto
- Graduate
School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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4
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Han HJ, Park SY, Jeon SE, Kwak JS, Lee JH, Jaladi AK, Hwang H, An DK. Grignard Reagent-Catalyzed Hydroboration of Esters, Nitriles, and Imines. Molecules 2023; 28:7090. [PMID: 37894569 PMCID: PMC10609653 DOI: 10.3390/molecules28207090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
The reduction in esters, nitriles, and imines requires harsh conditions (highly reactive reagents, high temperatures, and pressures) or complex metal-ligand catalytic systems. Catalysts comprising earth-abundant and less toxic elements are desirable from the perspective of green chemistry. In this study, we developed a green hydroboration protocol for the reduction in esters, nitriles, and imines at room temperature (25 °C) using pinacolborane as the reducing agent and a commercially available Grignard reagent as the catalyst. Screening of various alkyl magnesium halides revealed MeMgCl as the optimal catalyst for the reduction. The hydroboration and subsequent hydrolysis of various esters yielded corresponding alcohols over a short reaction time (~0.5 h). The hydroboration of nitriles and imines produced various primary and secondary amines in excellent yields. Chemoselective reduction and density functional theory calculations are also performed. The proposed green hydroboration protocol eliminates the requirements for complex ligand systems and elevated temperatures, providing an effective method for the reduction in esters, nitriles, and imines at room temperature.
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Affiliation(s)
| | | | | | | | | | | | | | - Duk Keun An
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea; (H.J.H.); (S.Y.P.); (S.E.J.); (J.S.K.); (J.H.L.); (A.K.J.); (H.H.)
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5
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André RF, Palazzolo A, Poucin C, Ribot F, Carenco S. Phosphine-Catalyzed Activation of Phenylsilane for Benzaldehyde Reduction. Chempluschem 2023; 88:e202300038. [PMID: 36861404 DOI: 10.1002/cplu.202300038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/03/2023]
Abstract
Hydrosilylation reactions are commonly used for the reduction of carbonyl bonds in fine chemistry, catalyzed by transition metal complexes. The current challenge is to expand the scope of metal-free alternative catalysts, including in particular organocatalysts. This work describes the organocatalyzed hydrosilylation of benzaldehyde with a phosphine, introduced at 10 mol%, and phenylsilane at room temperature. The activation of phenylsilane was highly dependent on the physical properties of the solvent such as the polarity, and the highest conversions were obtained in acetonitrile and propylene carbonate with yields of 46 % and 97 %, respectively. The best results of the screening over 13 phosphines and phosphites were obtained with linear trialkylphoshines (PMe3 , Pn Bu3 , POct3 ), indicating the importance of their nucleophilicity, with yields of 88 %, 46 % and 56 %, respectively. With the help of heteronuclear 1 H-29 Si NMR spectroscopy, the products of the hydrosilylation (PhSiH3-n (OBn)n ) were identified, allowing a monitoring of the concentration in the different species, and thereby of their reactivity. The reaction displayed an induction period of ca. 60 min, followed by the sequential hydrosilylations presenting various reaction rates. In agreement with the formation of partial charges in the intermediate state, we propose a mechanism based on a hypervalent silicon center via the Lewis base activation of the silicon Lewis acid.
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Affiliation(s)
- Rémi F André
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France
| | - Alberto Palazzolo
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France
| | - Cyprien Poucin
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France
| | - François Ribot
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France
| | - Sophie Carenco
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 place Jussieu, 75005, Paris, France
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6
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St Onge P, Khan SI, Cook A, Newman SG. Reductive Cleavage of C(sp 2)-CF 3 Bonds in Trifluoromethylpyridines. Org Lett 2023; 25:1030-1034. [PMID: 36749351 DOI: 10.1021/acs.orglett.3c00258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A reductive detrifluoromethylation protocol has been developed making use of an earth-abundant alkoxide base and silicon hydride species. A variety of pyridine and quinoline substrates bearing alkyl, aryl, and amino functional groups are reduced in moderate to high yields. The reaction is chemoselective for C(sp2)-CF3 groups located at the 2-position on the pyridine ring, leaving trifluoromethyl groups located elsewhere on the molecule intact. Preliminary mechanistic studies demonstrate that the combination of silane and base generates a strongly reducing system that may transfer an electron to electron-deficient π systems.
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Affiliation(s)
- Piers St Onge
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Shajia I Khan
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Adam Cook
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Stephen G Newman
- Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
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7
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Sarkar N, Kumar Sahoo R, Nembenna S. Aluminium-Catalyzed Selective Hydroboration of Esters and Epoxides to Alcohols: C-O Bond Activation. Chemistry 2023; 29:e202203023. [PMID: 36226774 DOI: 10.1002/chem.202203023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Indexed: 11/07/2022]
Abstract
In this work, the molecular aluminium dihydride complex bearing an N, N'-chelated conjugated bis-guanidinate (CBG) ligand is used as a catalyst for reducing a wide range of aryl and alkyl esters with good tolerance of alkene (C=C), alkyne (C≡C), halides (Cl, Br, I and F), nitrile (C≡N), and nitro (NO2 ) functionalities. Further, we investigated the catalytic application of aluminium dihydride in the C-O bond cleavage of alkyl and aryl epoxides into corresponding branched Markovnikov ring-opening products. In addition, the chemoselective intermolecular reduction of esters over other reducible functional groups, such as amides and alkenes, has been established. Intermediates are isolated and characterized by NMR and HRMS studies, which confirm the probable catalytic cycles for the hydroboration of esters and epoxides.
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Affiliation(s)
- Nabin Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
| | - Rajata Kumar Sahoo
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
| | - Sharanappa Nembenna
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, 752050, India
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8
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Putta RR, Chun S, Lee SB, Hong J, Choi SH, Oh DC, Hong S. Chemoselective α-Alkylation and α-Olefination of Arylacetonitriles with Alcohols via Iron-Catalyzed Borrowing Hydrogen and Dehydrogenative Coupling. J Org Chem 2022; 87:16378-16389. [PMID: 36417466 DOI: 10.1021/acs.joc.2c02050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
α-Alkyl and α-olefin nitriles are very important for organic synthesis and medicinal chemistry. However, different types of catalysts are employed to achieve either α-alkylation of nitriles by borrowing hydrogen or α-olefination by dehydrogenative coupling methods. Designing and developing high-performance earth-abundant catalysts that can procure different products from the same starting materials remain a great challenge. Herein, we report an iron(0) catalyst system that achieves chemoselectivity between borrowing hydrogen and dehydrogenative coupling protocols by simply changing the base. A broad range of nitriles and alcohols, including benzylic, linear aliphatic, cycloaliphatic, heterocyclic, and allylic alcohols, were selectively and efficiently converted to the corresponding products. Mechanistic studies reveal that the reaction mechanism proceeds through a dehydrogenative pathway. This iron catalytic protocol is environmentally benign and atom-efficient with the liberation of H2 and H2O as green byproducts.
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Affiliation(s)
- Ramachandra Reddy Putta
- BK 21 Plus Project, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Simin Chun
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Seok Beom Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Junhwa Hong
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Seung Hyun Choi
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Dong-Chan Oh
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Suckchang Hong
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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9
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Peng Y, Oestreich M. B(C 6F 5) 3-Catalyzed Reductive Denitrogenation of Benzonitrile Derivatives. Org Lett 2022; 24:2940-2943. [PMID: 35417183 DOI: 10.1021/acs.orglett.2c01003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A B(C6F5)3-catalyzed reductive denitrogenation of aromatic nitriles is reported, achieving the metal-free transformation of a cyano into a methyl group in a single synthetic operation. Tris(phenylsilyl)amine is liberated as the nitrogen-containing byproduct. On the basis of control experiments as well as a nuclear magnetic resonance spectroscopic analysis, an SN1-type mechanism involving a trisilylammonium ion as a key intermediate is proposed.
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Affiliation(s)
- Yi Peng
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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10
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Kehner R, Hewitt MC, Bayeh-Romero L. Expanding Zirconocene Hydride Catalysis: In Situ Generation and Turnover of ZrH Catalysts Enabling Catalytic Carbonyl Reductions. ACS Catal 2022; 12:1758-1763. [PMID: 35685613 PMCID: PMC9169672 DOI: 10.1021/acscatal.2c00079] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/12/2022] [Indexed: 01/21/2023]
Abstract
Despite the wide use and popularity of metal hydride catalysis, methods utilizing zirconium hydride catalysts remain underexplored. Here, we report the development of a mild method for the in situ preparation and use of zirconium hydride catalysts. This robust method requires only 2.5-5 mol % of zirconocene dichloride in combination with a hydrosilane as the stoichiometric reductant and does not require careful air- or moisture-free techniques. A key finding of this study concerns an amine-mediated ligand exchange en route to the active zirconocene hydride catalyst. A mechanistic investigation supports the intermediacy of an oxo-bridged dimer precatalyst. The application of this method to the reduction of a wide variety of carbonyl-containing substrates, including ketones, aldehydes, enones, ynones, and lactones, is demonstrated with up to 92% yield and exhibits broad functional group tolerability. These findings open up alternative avenues for the catalytic application of chlorozirconocenes, potentially serving as the foundation for broader applications of zirconium hydride catalysis.
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11
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Popov KK, Campbell JLP, Kysilka O, Hošek J, Davies CD, Pour M, Kočovský P. Reductive Amination Revisited: Reduction of Aldimines with Trichlorosilane Catalyzed by Dimethylformamide─Functional Group Tolerance, Scope, and Limitations. J Org Chem 2021; 87:920-943. [PMID: 34841878 DOI: 10.1021/acs.joc.1c01561] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aldimines, generated in situ from aliphatic, aromatic, and heteroaromatic aldehydes and aliphatic, aromatic, and heteroaromatic primary or secondary amines, can be reduced with trichlorosilane in the presence of dimethylformamide (DMF) as an organocatalyst (≤10 mol %) in toluene or CH2Cl2 at room temperature. The reduction tolerates ketone carbonyls, esters, amides, nitriles, sulfones, sulfonamides, NO2, SF5, and CF3 groups, boronic esters, azides, phosphine oxides, C═C and C≡C bonds, and ferrocenyl nucleus, but sulfoxides and N-oxides are reduced. α,β-Unsaturated aldimines undergo 1,2-reduction only, leaving the C═C bond intact. N-Monoalkylation of primary amines is attained with a 1:1 aldehyde to amine ratio, whereas excess of the aldehyde (≥2:1) allows second alkylation, giving rise to tertiary amines. Reductive N-alkylation of α-amino acids proceeds without racemization; the resulting products, containing a C≡C bond or N3 group, are suitable for click chemistry. This reaction thus offers advantages over the traditional methods (borohydride reduction or catalytic hydrogenation) in terms of efficiency and chemoselectivity. Solubility of some of the reacting partners appears to be the only limitation. The byproducts generated by the workup with aqueous NaHCO3 (i.e., NaCl and silica) are environmentally benign. As a greener alternative, DMA can be employed as a catalyst instead of DMF.
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Affiliation(s)
- Kirill K Popov
- Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic
| | - Joanna L P Campbell
- Syngenta, Grangemouth Manufacturing Centre, Earl's Road, Grangemouth FK3 8XG, U.K
| | - Ondřej Kysilka
- Trelleborg Bohemia, Akademika Bedrny 531/8a, Věkoše, 500 03 Hradec Králové Czech Republic
| | - Jan Hošek
- Farmak, Na vlčinci 16/3, Klášterní Hradisko, 77900 Olomouc, Czech Republic
| | | | - Milan Pour
- Department of Organic and Bioorganic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Pavel Kočovský
- Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic.,Department of Organic and Bioorganic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
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