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Liu H, Xu B. Gold-Catalyzed C-N Cross-Coupling Reactions of Aryl Iodides with Alkyl Nitriles or Silver Cyanate. Org Lett 2024; 26:5430-5435. [PMID: 38912725 DOI: 10.1021/acs.orglett.4c01538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
We have gold-catalyzed C-N cross-couplings of aryl iodides with aliphatic nitriles. Although nitriles are usually challenging nitrogen cross-coupling partners, they could be activated by base-mediated deprotonation and isomerization. The method utilizes widely available substrates in moderate to good yields to provide various N-aryl compounds. In addition, a similar strategy could be extended to the cross-couplings of aryl iodides with silver cyanate. The protocol features high humidity/air tolerance and works inter- and intramolecularly.
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Affiliation(s)
- Hongyan Liu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China
| | - Bo Xu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China
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2
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Font P, Valdés H, Ribas X. Consolidation of the Oxidant-Free Au(I)/Au(III) Catalysis Enabled by the Hemilabile Ligand Strategy. Angew Chem Int Ed Engl 2024; 63:e202405824. [PMID: 38687322 DOI: 10.1002/anie.202405824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/02/2024]
Abstract
In this minireview we survey the challenges and strategies in gold redox catalysis. Gold's reluctance to oxidative addition reactions due to its high redox potential limits its applicability. Initial attempts to overcome this problem focused on the use of sacrificial external oxidants in stoichiometric amounts to bring Au(I) compounds to Au(III) reactive species. Recently, innovative approaches focused on employing hemilabile ligands, which are capable of coordinating to Au(I) and stabilizing square-planar Au(III) intermediates, thus facilitating oxidative addition steps and enabling oxidant-free catalysis. Notable examples include the use of the (P^N) bidendate MeDalphos ligand to achieve various cross-coupling reactions via oxidative addition Au(I)/Au(III). Importantly, hemilabile ligand-enabled catalysis allows merging oxidative addition with π-activation, such as oxy- and aminoarylation of alkenols and alkenamines using organohalides, expanding gold's versatility in C-C and C-heteroatom bond formations and unprecedented cyclizations. Moreover, recent advancements in enantioselective catalysis using chiral hemilabile (P^N) ligands are also surveyed. Strikingly, versatile bidentate (C^N) hemilabile ligands as competitors of MeDalphos have appeared recently, by designing scaffolds where phosphine groups are substituted by N-heterocyclic or mesoionic carbenes. Overall, these approaches highlight the evolving landscape of gold redox catalysis and its tremendous potential in a broad scope of transformations.
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Affiliation(s)
- Pau Font
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, E-17003, Catalonia, Spain
| | - Hugo Valdés
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, E-17003, Catalonia, Spain
- Current address: Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28805, Alcalá de Henares, Madrid, Spain
| | - Xavi Ribas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, E-17003, Catalonia, Spain
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3
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Kunkel G, Zhou Q, Treacy JW, Montgomery HR, Salas-Ambrosio P, Ready AD, Spokoyny AM, Houk KN, Maynard HD. Comparison of Cyclic and Linear PEG Conjugates. Bioconjug Chem 2024; 35:744-749. [PMID: 38809040 PMCID: PMC11191396 DOI: 10.1021/acs.bioconjchem.4c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/17/2024] [Accepted: 05/21/2024] [Indexed: 05/30/2024]
Abstract
Bioconjugation of polymers to proteins is a method to impart improved stability and pharmacokinetic properties to biologic systems. However, the precise effects of polymer architecture on the resulting bioconjugates are not well understood. Particularly, cyclic polymers are known to possess unique features such as a decreased hydrodynamic radius when compared to their linear counterparts of the same molecular weight, but have not yet been studied. Here, we report the first bioconjugation of a cyclic polymer, poly(ethylene glycol) (PEG), to a model protein, T4 lysozyme, containing a single engineered cysteine residue (V131C). We compare the stability and activity of this conjugate with those of a linear PEG-T4 lysozyme analogue of similar molecular weight. Furthermore, we used molecular dynamics (MD) simulations to determine the behavior of the polymer-protein conjugates in solution. We introduce cyclic polymer-protein conjugates as potential candidates for the improvement of biologic therapeutics.
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Affiliation(s)
- Grace
E. Kunkel
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Qingyang Zhou
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Joseph W. Treacy
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Hayden R. Montgomery
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Pedro Salas-Ambrosio
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Austin D. Ready
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Alexander M. Spokoyny
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Kendall N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Heather D. Maynard
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
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4
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Vesseur D, Li S, Mallet-Ladeira S, Miqueu K, Bourissou D. Ligand-Enabled Oxidative Fluorination of Gold(I) and Light-Induced Aryl-F Coupling at Gold(III). J Am Chem Soc 2024. [PMID: 38607393 DOI: 10.1021/jacs.4c00913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
MeDalphos Au(I) complexes featuring aryl, alkynyl, and alkyl groups readily react with electrophilic fluorinating reagents such as N-fluorobenzenesulfonimide and Selectfluor. The ensuing [(MeDalphos)Au(R)F]+ complexes have been isolated and characterized by multinuclear NMR spectroscopy as well as X-ray diffraction. They adopt a square-planar contra-thermodynamic structure, with F trans to N. DFT/IBO calculations show that the N lone pair of MeDalphos assists and directs the transfer of F+ to gold. The [(MeDalphos)Au(Ar)F]+ (Ar = Mes, 2,6-F2Ph) complexes smoothly engage in C-C cross-coupling with PhCCSiMe3 and Me3SiCN, providing direct evidence for the oxidative fluorination/transmetalation/reductive elimination sequence proposed for F+-promoted gold-catalyzed transformations. Moreover, direct reductive elimination to forge a C-F bond at Au(III) was explored and substantiated. Thermal means proved unsuccessful, leading mostly to decomposition, but irradiation with UV-visible light enabled efficient promotion of aryl-F coupling (up to 90% yield). The light-induced reductive elimination proceeds under mild conditions; it works even with the electron-deprived 2,6-difluorophenyl group, and it is not limited to the contra-thermodynamic form of the aryl Au(III) fluoride complexes.
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Affiliation(s)
- David Vesseur
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Shuo Li
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Sonia Mallet-Ladeira
- Institut de Chimie de Toulouse (UAR 2599) , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
| | - Karinne Miqueu
- E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM, UMR 5254), CNRS/Université de Pau et des Pays de l'Adour, Hélioparc, 2 Avenue du Président Angot, 64053 Pau, Cedex 09, France
| | - Didier Bourissou
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069) , CNRS/Université Paul Sabatier , 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France
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Muratov K, Zaripov E, Berezovski MV, Gagosz F. DFT-Enabled Development of Hemilabile (P ∧N) Ligands for Gold(I/III) RedOx Catalysis: Application to the Thiotosylation of Aryl Iodides. J Am Chem Soc 2024; 146:3660-3674. [PMID: 38315643 DOI: 10.1021/jacs.3c08943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Ligand-enabled oxidative addition of Csp2-X bonds to Au(I) centers has recently appeared as a valuable strategy for the development of catalytic RedOx processes. Several cross-coupling reactions that were previously considered difficult to achieve were reported lately, thus expanding the synthetic potential of gold(I) complexes beyond the traditional nucleophilic functionalization of π-systems. MeDalPhos has played an important role in this development and, despite several studies on alternative structures, remains, so far, the only general ligand for such process. We report herein the discovery and DFT-enabled structural optimization of a new family of hemilabile (P∧N) ligands that can promote the oxidative addition of aryl iodides to gold(I). These flexible ligands, which possess a common 2-methylamino heteroaromatic N-donor motif, are structurally and electronically tunable, beyond being easily accessible and affordable. The corresponding Au(I) complexes were shown to outperform the reactivity of (MeDalPhos)Au(I) in a series of alkoxy- and amidoarylations of alkenes. Their synthetic potential and comparatively higher reactivity were further highlighted in the thiotosylation of aryl iodides, a challenging unreported C-S cross-coupling reaction that could not be achieved under classical Pd(0/II) catalysis and that allows for general and divergent access to aryl sulfur derivatives.
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Affiliation(s)
- Karim Muratov
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Emil Zaripov
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Maxim V Berezovski
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Fabien Gagosz
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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Chen G, Xu B. Gold-Catalyzed C-O Cross-Coupling Reactions of Aryl Iodides with Silver Carboxylates. Org Lett 2023; 25:6334-6339. [PMID: 37602793 DOI: 10.1021/acs.orglett.3c02254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
We have developed a C-O cross-coupling reaction of (hetero)aryl iodides with silver carboxylates via a AuI/AuIII catalytic cycle. The transformation featured exclusive chemoselectivity and moisture/air insensitivity. Aromatic and aliphatic (including primary, secondary, and tertiary) silver carboxylates are all suitable substrates. Moreover, this protocol worked well intermolecularly and intramolecularly. Most importantly, good yields were obtained regardless of the substrates' electronic effect and steric hindrance.
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Affiliation(s)
- Guifang Chen
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
| | - Bo Xu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
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