1
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Balhara R, Chatterjee R, Jindal G. Mechanism and stereoselectivity in metal and enzyme catalyzed carbene insertion into X-H and C(sp 2)-H bonds. Chem Soc Rev 2024. [PMID: 39392229 DOI: 10.1039/d4cs00742e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
Constructing highly proficient C-X (X = O, N, S, etc.) and C-C bonds by leveraging TMs (transition metals) (Fe, Cu, Pd, Rh, Au, etc.) and enzymes to catalyze carbene insertion into X-H/C(sp2)-H is a highly versatile strategy. This is primarily achieved through the in situ generation of metal carbenes from the interaction of TMs with diazo compounds. Over the last few decades, significant advancements have been made, encompassing a wide array of X-H bond insertions using various TMs. These reactions typically favor a stepwise ionic pathway where the nucleophilic attack on the metal carbene leads to the generation of a metal ylide species. This intermediate marks a critical juncture in the reaction cascade, presenting multiple avenues for proton transfer to yield the X-H inserted product. The mechanism of C(sp2)-H insertion reactions closely resembles those of X-H insertion reactions and thus have been included here. A major development in carbene insertion reactions has been the use of engineered enzymes as catalysts. Since the seminal report of a non-natural "carbene transferase" by Arnold in 2013, "P411", several heme-based enzymes have been reported in the literature to catalyze various abiological carbene insertion reactions into C(sp2)-H, N-H and S-H bonds. These enzymes possess an extraordinary ability to regulate the orientation and conformations of reactive intermediates, facilitating stereoselective carbene transfers. However, the absence of a suitable stereochemical model has impeded the development of asymmetric reactions employing a lone chiral catalyst, including enzymes. There is a pressing need to investigate alternative mechanisms and models to enhance our comprehension of stereoselectivity in these processes, which will be crucial for advancing the fields of asymmetric synthesis and biocatalysis. The current review aims to provide details on the mechanistic aspects of the asymmetric X-H and C(sp2)-H insertion reactions catalyzed by Fe, Cu, Pd, Rh, Au, and enzymes, focusing on the detailed mechanism and stereochemical model. The review is divided into sections focusing on a specific X-H/C(sp2)-H bond type catalyzed by different TMs and enzymes.
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Affiliation(s)
- Reena Balhara
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru-560012, Karnataka, India.
| | - Ritwika Chatterjee
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru-560012, Karnataka, India.
| | - Garima Jindal
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru-560012, Karnataka, India.
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2
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Peeters M, Baldinelli L, Leutzsch M, Caló F, Auer AA, Bistoni G, Fürstner A. In Situ Observation of Elusive Dirhodium Carbenes and Studies on the Innate Role of Carboxamidate Ligands in Dirhodium Paddlewheel Complexes: A Combined Experimental and Computational Approach. J Am Chem Soc 2024; 146:26466-26477. [PMID: 39259974 PMCID: PMC11440507 DOI: 10.1021/jacs.4c09847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Carboxamidates as equatorial ligands in dirhodium paddlewheel catalysts are widely believed to increase selectivity at the expense of reactivity. The results of the combined experimental and computational approach described in this paper show that one has to beware of such generalizations. First, 103Rh NMR revealed how strongly primary carboxamidates impact the electronic nature of the rhodium center they are bound to; at the same time, such ligands stabilize donor/acceptor carbenes by engaging their ester carbonyl group into peripheral interligand hydrogen bonding. This array benefits selectivity as well as reactivity if maintained along the entire reaction coordinate of a catalytic cyclopropanation. In settings where the hydrogen bond needs to be distorted for the reaction to proceed, however, it constitutes a significant enthalpic handicap. Representative examples for each scenario were analyzed by DFT; in both cases, the cyclopropanation step rather than carbene formation was found to be turnover-limiting. While this conclusion somehow contradicts the literature, it implied that the direct observation of highly reactive dirhodium carbenes in truly catalytic settings might be possible, even though the intermediates carry olefinic sites amenable to intramolecular cyclopropanation. Such in situ monitoring by NMR is without precedent, yet it was successful with the homoleptic catalyst [Rh2(OPiv)4] as well as with its heteroleptic sibling [Rh2(OPiv)3(acam)] comprising an acetamidate (acam); in the latter case, the carbene bound to the rhodium atom at the [O3N]-face was observed, which concurs with the computational data that this species is stabilized by the forecited interligand hydrogen bonding.
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Affiliation(s)
- Matthias Peeters
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Lorenzo Baldinelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, Perugia I-06123, Italy
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Fabio Caló
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Alexander A Auer
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Giovanni Bistoni
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, Perugia I-06123, Italy
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
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3
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Li W, Wu R, Ruan H, Xiao B, Gao X, Jiang H, Chen K, Sun TY, Zhu S. Axial Ligand Enables Synthesis of Allenylsilane through Dirhodium(II) Catalysis. Angew Chem Int Ed Engl 2024; 63:e202409332. [PMID: 38887822 DOI: 10.1002/anie.202409332] [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: 05/16/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
Described herein is a dirhodium(II)-catalyzed silylation of propargyl esters with hydrosilanes, using tertiary amines as axial ligands. By adopting this strategy, a range of versatile and useful allenylsilanes can be achieved with good yields. This reaction not only represents a SN2'-type silylation of the propargyl derivatives bearing a terminal alkyne moiety to synthesize allenylsilanes from simple hydrosilanes, but also represents a new application of dirhodium(II) complexes in catalytic transformation of carbon-carbon triple bond. The highly functionalized allenylsilanes that are produced can be transformed into a series of synthetically useful organic molecules. In this reaction, an intriguing ON-OFF effect of the amine ligand was observed. The reaction almost did not occur (OFF) without addition of Lewis base amine ligand. However, the reaction took place smoothly (ON) after addition of only catalytic amount of amine ligand. Detailed mechanistic studies and density functional theory (DFT) calculations indicate that the reactivity can be delicately improved by the use of tertiary amine. The fine-tuning effect of the tertiary amine is crucial in the formation of the Rh-Si species via a concerted metalation deprotonation (CMD) mechanism and facilitating β-oxygen elimination.
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Affiliation(s)
- Wendeng Li
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Rui Wu
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Hao Ruan
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Bo Xiao
- Key Lab of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, P. R. China
| | - Xiang Gao
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Huanfeng Jiang
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Tian-Yu Sun
- Key Lab of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, P. R. China
- Institute of Molecular Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, 518132, P. R. China
| | - Shifa Zhu
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, P. R. China
- School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China
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4
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Tantillo DJ. Quantum Chemical Interrogation of Reactions Promoted by Dirhodium Tetracarboxylate Catalysts─Mechanism, Selectivity, and Nonstatistical Dynamic Effects. Acc Chem Res 2024; 57:1931-1940. [PMID: 38920276 DOI: 10.1021/acs.accounts.4c00214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
ConspectusRh2L4 catalysts have risen in popularity in the world of organic synthesis, being used to accomplish a variety of reactions, including C-H insertion and cyclopropanation, and often doing so with high levels of stereocontrol. While the mechanisms and origins of selectivity for such reactions have been examined with computational quantum chemistry for decades, only recently have detailed pictures of the dynamic behavior of reacting Rh2L4-complexed molecules become accessible. Our computational studies on Rh2L4 catalyzed reactions are described here, with a focus on C-H insertion reactions of Rh2L4-carbenes. Several issues complicate the modeling of these reactions, each providing an opportunity for greater understanding and each revealing issues that should be incorporated into future rational design efforts. First, the fundamental mechanism of C-H insertion is discussed. While early quantum chemical studies pointed to transition structures with 3-center [C-H-C] substructures and asynchronous hydride transfer/C-C bond formation, recent examples of reactions with particularly flat potential energy surfaces and even discrete zwitterionic intermediates have been found. These reactions are associated with systems bearing π-donating groups at the site of hydride transfer, allowing for an intermediate with a carbocation substructure at that site to be selectively stabilized. Second, the possible importance of solvent coordination at the Rh atom distal to the carbene is discussed. While effects on reactivity and selectivity were found to be small, they turn out not to be negligible in some cases. Third, it is shown that, in contrast to many other transition metal promoted reactions, many Rh2L4 catalyzed reactions likely involve dissociation of the Rh2L4 catalyst before key chemical steps leading to products. When to expect dissociation is associated with specific features of substrates and the product-forming reactions in question. Often, dissociation precedes transition structures for pericyclic reactions that involve electrons that would otherwise bind to Rh2L4. Finally, the importance of nonstatistical dynamic effects, characterized through ab initio molecular dynamics studies, in some Rh2L4 catalyzed reactions is discussed. These are reactions where transition structures are shown to be followed by flat regions, very shallow minima, and/or pathways that bifurcate, all allowing for trajectories from a single transition state to form multiple different products. The likelihood of encountering such a situation is shown to be associated again with the likelihood of formation of zwitterionic structures along reaction paths, but ones for which pathways to multiple products are expected to be associated with very low or no barriers. The connection between these features and reduced yields of desired products are highlighted, as are the means by which some Rh2L4 catalysts modulate dynamic behavior to produce particular products in high yield.
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Affiliation(s)
- Dean J Tantillo
- Department of Chemistry, University of California─Davis, 1 Shields Avenue, Davis, California 95616, United States
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5
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Cosio M, Lee SR, Lai Q, Bhuvanesh N, Zhou J, Ozerov OV. Dimeric Rh Complexes Supported by a Bridging Phosphido/Bis(Phosphine) PPP Ligand. Organometallics 2024; 43:947-953. [PMID: 38756991 PMCID: PMC11094786 DOI: 10.1021/acs.organomet.3c00492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 05/18/2024]
Abstract
Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a phosphide. Three bimetallic Rh complexes containing the diamandoid Rh2P2 core (P = phosphido) have been structurally and spectroscopically characterized. The Rh-Rh interaction in these three dimers was examined by way of structural comparisons and DFT investigations.
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Affiliation(s)
- Mario
N. Cosio
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Samuel R. Lee
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Qingheng Lai
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Nattamai Bhuvanesh
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Jia Zhou
- State
Key Laboratory of Urban Water Resource and Environment, School of
Science, Harbin Institute of Technology, Shenzhen 518055, China
| | - Oleg V. Ozerov
- Department
of Chemistry, Texas A&M University, College Station, Texas 77842, United States
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6
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Hess KM, Leach IF, Wijtenhorst L, Lee H, Klein JEMN. Valence Tautomerism Induced Proton Coupled Electron Transfer:X-H Bond Oxidation with a Dinuclear Au(II) Hydroxide Complex. Angew Chem Int Ed Engl 2024; 63:e202318916. [PMID: 38324462 DOI: 10.1002/anie.202318916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/09/2024]
Abstract
We report the preparation and characterization of the dinuclear AuII hydroxide complex AuII 2(L)2(OH)2 (L=N,N'-bis (2,6-dimethyl) phenylformamidinate) and study its reactivity towards weak X-H bonds. Through the interplay of kinetic analysis and computational studies, we demonstrate that the oxidation of cyclohexadiene follows a concerted proton-coupled electron transfer (cPCET) mechanism, a rare type of reactivity for Au complexes. We find that the Au-Au σ-bond undergoes polarization in the PCET event leading to an adjustment of oxidation levels for both Au centers prior to C(sp3)-H bond cleavage. We thus describe the oxidation event as a valence tautomerism-induced PCET where the basicity of one reduced Au-OH unit provides a proton acceptor and the second more oxidized Au center serves as an electron acceptor. The coordination of these events allows for unprecedented radical-type reactivity by a closed shell AuII complex.
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Affiliation(s)
- Kristopher M Hess
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Isaac F Leach
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Lisa Wijtenhorst
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Hangyul Lee
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG Groningen, The Netherlands
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7
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Gui X, Sorbelli D, Caló FP, Leutzsch M, Patzer M, Fürstner A, Bistoni G, Auer AA. Elucidating the Electronic Nature of Rh-based Paddlewheel Catalysts from 103 Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations. Chemistry 2024; 30:e202301846. [PMID: 37721802 DOI: 10.1002/chem.202301846] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 09/20/2023]
Abstract
The tremendous importance of dirhodium paddlewheel complexes for asymmetric catalysis is largely the result of an empirical optimization of the chiral ligand sphere about the bimetallic core. It was only recently that a H(C)Rh triple resonance 103 Rh NMR experiment provided the long-awaited opportunity to examine - with previously inconceivable accuracy - how variation of the ligands impacts on the electronic structure of such catalysts. The recorded effects are dramatic: formal replacement of only one out of eight O-atoms surrounding the metal centers in a dirhodium tetracarboxylate by an N-atom results in a shielding of the corresponding Rh-site of no less than 1000 ppm. The current paper provides the theoretical framework that allows this and related experimental observations made with a set of 19 representative rhodium complexes to be interpreted. In line with symmetry considerations, it is shown that the shielding tensor responds only to the donor ability of the equatorial ligands along the perpendicular principal axis. Axial ligands, in contrast, have no direct effect on shielding but may come into play via the electronicc i s ${cis}$ -effect that they exert onto the neighboring equatorial sites. On top of these fundamental interactions, charge redistribution within the core as well as the electronict r a n s ${trans}$ -effect of ligands of different donor strengths is reflected in the recorded 103 Rh NMR shifts.
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Affiliation(s)
- Xin Gui
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Diego Sorbelli
- Dipartmento di Chimica, Biologia e Biotechnologie, Università Degli Studi Di Perugia, 06123, Perugia, Italy
| | - Fabio P Caló
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Michael Patzer
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
- Dipartmento di Chimica, Biologia e Biotechnologie, Università Degli Studi Di Perugia, 06123, Perugia, Italy
| | - Alexander A Auer
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
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8
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Harbor-Collins H, Sabba M, Bengs C, Moustafa G, Leutzsch M, Levitt MH. NMR spectroscopy of a 18O-labeled rhodium paddlewheel complex: Isotope shifts, 103Rh-103Rh spin-spin coupling, and 103Rh singlet NMR. J Chem Phys 2024; 160:014305. [PMID: 38174793 DOI: 10.1063/5.0182233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/10/2023] [Indexed: 01/05/2024] Open
Abstract
Despite the importance of rhodium complexes in catalysis, and the favorable 100% natural abundance of the spin-1/2 103Rh nucleus, there are few reports of 103Rh nuclear magnetic resonance (NMR) parameters in the literature. In part, this is the consequence of the very low gyromagnetic ratio of 103Rh and its dismal NMR sensitivity. In a previous paper [Harbor-Collins et al., J. Chem. Phys. 159, 104 307 (2023)], we demonstrated an NMR methodology for 1H-enhanced 103Rh NMR and demonstrated an application to the 103Rh NMR of the dirhodium formate paddlewheel complex. In this paper, we employ selective 18O labeling to break the magnetic equivalence of the 103Rh spin pair of dirhodium formate. This allows the estimation of the 103Rh-103Rh spin-spin coupling and provides access to the 103Rh singlet state. We present the first measurement of a 18O-induced 103Rh secondary isotope shift as well as the first instance of singlet order generated in a 103Rh spin pair. The field-dependence of 103Rh singlet relaxation is measured by field-cycling NMR experiments.
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Affiliation(s)
- Harry Harbor-Collins
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Mohamed Sabba
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Christian Bengs
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Gamal Moustafa
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
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9
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Harariya MS, Gogoi R, Goswami A, Sharma AK, Jindal G. Is Enol Always the Culprit? The Curious Case of High Enantioselectivity in a Chiral Rh(II) Complex Catalyzed Carbene Insertion Reaction. Chemistry 2023; 29:e202301910. [PMID: 37665257 DOI: 10.1002/chem.202301910] [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: 06/16/2023] [Revised: 09/04/2023] [Accepted: 09/04/2023] [Indexed: 09/05/2023]
Abstract
The mechanism of Rh2 (S-NTTL)4 catalyzed carbene insertion into C(3)-H of indole is investigated using DFT methods. Since the commonly accepted enol mechanism cannot account for enantioinduction, a concerted oxocarbenium pathway was proposed in an earlier work using a model catalyst. However, after considering the full catalytic system, this study finds that akin to other reactions, here, too, the enol pathway is of lower energy, which now naturally raises a conundrum regarding the mode of chiral induction. Herein, a new water promoted mechanistic pathway involving a metal-associated enol intermediate hydrogen bonding and stereochemical model are proposed to solve this puzzle. It is shown how the catalyst bowl-shaped structure along with substrate-catalyst binding is crucial for achieving high levels of enantioselectivity. A stereodetermining water-assisted proton transfer is proposed and confirmed through deuterium-labeling experiments. The water molecules are held together by H-bonding interactions with the carboxylate ligands that is reminiscent of enzyme catalysis. Although several previous studies have aimed at understanding the mechanism of metal catalyzed carbene insertion reactions, the origin of high stereoinduction especially with chiral metal complexes remains unclear, and till date there is no transition state model that can explain the high enantioselectivity with such chiral Rh complexes. The metal-associated enol pathway is currently underrepresented in catalytic cycles and may play a crucial role in catalyst design. Since the enol pathway is commonly adopted in other metal-catalyzed X-H insertion reactions involving a diazoester, the presented results are not specific to the current reaction. Therefore, this study could provide the direction for achieving high levels of enantioselectivity which is otherwise difficult to achieve with a single metal catalyst.
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Affiliation(s)
- Mahesh S Harariya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Romin Gogoi
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Anubhav Goswami
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Akhilesh K Sharma
- Institute of Chemical Research of Catalonia (ICIQ), Avgda. Països Catalans, 1643007, Tarragona, 560012, Spain
| | - Garima Jindal
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka, 560012, India
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10
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Abshire A, Ogunyemi B, Darko A. Rh(II)-Catalyzed Si-H Insertion with Nosyl-hydrazone-Protected Aryl Donor Diazo Compounds. ACS OMEGA 2023; 8:38005-38012. [PMID: 37867650 PMCID: PMC10586302 DOI: 10.1021/acsomega.3c03519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 09/07/2023] [Indexed: 10/24/2023]
Abstract
Dirhodium(II,II) paddlewheel catalysts were evaluated in silyl-hydrogen insertion reactions of aryl diazo compounds generated from o-nosyl hydrazones. The high reactivity of aryl diazo compounds necessitates their in situ generation from sulfonyl-protected hydrazones. Herein, we describe our efforts to evaluate this transformation utilizing Rh(II) catalysts, including those with tethered, axially coordinating ligands. The heteroleptic catalyst, Rh2(OAc)3(2-OX), provided the highest yield of silanes when dioxane was the solvent.
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Affiliation(s)
- Anthony Abshire
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
| | - Bukola Ogunyemi
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
| | - Ampofo Darko
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
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11
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Hong K, Zhou Y, Yuan H, Zhang Z, Huang J, Dong S, Hu W, Yu ZX, Xu X. Catalytic 4-exo-dig carbocyclization for the construction of furan-fused cyclobutanones and synthetic applications. Nat Commun 2023; 14:6378. [PMID: 37821471 PMCID: PMC10567718 DOI: 10.1038/s41467-023-42032-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
Cyclobutanone is a strained motif with broad applications, while direct assembly of the aromatic ring fused cyclobutanones beyond benzocyclobutenone (BCB) skeletons remains challenging. Herein, we report a Rh-catalyzed formal [3+2] annulation of diazo group tethered alkynes involving a 4-exo-dig carbocyclization process, providing a straightforward access to furan-fused cyclobutanones. DFT calculations disclose that, by comparison to the competitive 5-endo-dig process, 4-exo-dig carbocyclization is mainly due to lower angle strain of the key sp-hybridized vinyl cationic transition state in the cyclization step. Using less reactive catalysts Rh2(carboxylate)4 is critical for high selectivity, which is explained as catalyst-substrate hydrogen bonding interaction. This method is proved successful to direct access previously inaccessible and unknown furan-fused cyclobutanone scaffolds, which can participate in a variety of post-functionalization reactions as versatile synthetic blocks. In addition, preliminary antitumor activity study of these products indicates that some molecules exhibite significant anticancer potency against different human cancer cell lines.
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Affiliation(s)
- Kemiao Hong
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Yi Zhou
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, 100871, Beijing, China
| | - Haoxuan Yuan
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Zhijing Zhang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Jingjing Huang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Shanliang Dong
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Wenhao Hu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China
| | - Zhi-Xiang Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, 100871, Beijing, China.
| | - Xinfang Xu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, Guangdong, China.
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12
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Díaz-Jiménez À, Monreal-Corona R, Poater A, Álvarez M, Borrego E, Pérez PJ, Caballero A, Roglans A, Pla-Quintana A. Intramolecular Interception of the Remote Position of Vinylcarbene Silver Complex Intermediates by C(sp 3 )-H Bond Insertion. Angew Chem Int Ed Engl 2023; 62:e202215163. [PMID: 36345831 PMCID: PMC10108323 DOI: 10.1002/anie.202215163] [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: 10/17/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
The trapping of the elusive vinylogous position of a vinyl carbene with an aliphatic C(sp3 )-H bond has been achieved for the first time during a silver-catalyzed carbene/alkyne metathesis (CAM) process. A Tpx -containing silver complex first promotes the generation of a donor-acceptor silver carbene which triggers CAM, generating a subsequent donor-donor vinyl silver carbene species, which then undergoes a selective vinylogous C(sp3 )-H bond insertion, leading to the synthesis of a new family of benzoazepines. Density functional theory (DFT) calculations unveil the reaction mechanism, which allows proposing that the C-H bond insertion reaction takes place in a stepwise manner, with the hydrogen shift being the rate determining step.
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Affiliation(s)
- Àlex Díaz-Jiménez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Facultat de Ciències, C/ Maria Aurèlia Capmany, 69, 17003 Catalunya, Girona, Spain
| | - Roger Monreal-Corona
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Facultat de Ciències, C/ Maria Aurèlia Capmany, 69, 17003 Catalunya, Girona, Spain
| | - Albert Poater
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Facultat de Ciències, C/ Maria Aurèlia Capmany, 69, 17003 Catalunya, Girona, Spain
| | - María Álvarez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, Edificio Robert H. Grubbs, Campus de El Carmen, 21007, Huelva, Spain
| | - Elena Borrego
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, Edificio Robert H. Grubbs, Campus de El Carmen, 21007, Huelva, Spain
| | - Pedro J Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, Edificio Robert H. Grubbs, Campus de El Carmen, 21007, Huelva, Spain
| | - Ana Caballero
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, Edificio Robert H. Grubbs, Campus de El Carmen, 21007, Huelva, Spain
| | - Anna Roglans
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Facultat de Ciències, C/ Maria Aurèlia Capmany, 69, 17003 Catalunya, Girona, Spain
| | - Anna Pla-Quintana
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona (UdG), Facultat de Ciències, C/ Maria Aurèlia Capmany, 69, 17003 Catalunya, Girona, Spain
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13
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Zavala C, Darko A. Effect of Tethered, Axially Coordinated Ligands (TACLs) on Dirhodium(II,II) Catalyzed Cyclopropanation: A Linear Free Energy Relationship Study. J Org Chem 2022; 87:6910-6917. [PMID: 35536597 DOI: 10.1021/acs.joc.2c00020] [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
Hammett correlation experiments were used to determine the influence of dirhodium(II,II) paddlewheel complexes with tethered, axially coordinated ligands (TACLs) on the selectivity of rhodium carbenoids in competitive cyclopropanation reactions. The results suggest that dirhodium(II,II) paddlewheel complexes with TACLs are less sensitive to changes in electronics and reduce selectivity in cyclopropanation reactions with acceptor-substituted rhodium carbenoids. Also, Hammett plots with aryl diazoacetates resulted in a nonlinear downward curvature, suggesting a change in the rate-limiting step of the carbene transfer reaction.
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Affiliation(s)
- Cristian Zavala
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
| | - Ampofo Darko
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States
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14
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Paddlewheel dirhodium(II) complexes with N-heterocyclic carbene or phosphine ligand: New reactivity and selectivity. GREEN SYNTHESIS AND CATALYSIS 2022. [DOI: 10.1016/j.gresc.2022.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Loreto D, Esposito A, Demitri N, Guaragna A, Merlino A. Reactivity of a fluorine-containing dirhodium tetracarboxylate compound with proteins. Dalton Trans 2022; 51:3695-3705. [PMID: 35166290 DOI: 10.1039/d2dt00082b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dirhodium complexes of general formula [Rh2(O2CR)4]L2 are a well-known class of bimetallic compounds that are used as efficient catalysts for a variety of reactions and have been shown to be potent antibacterial and anticancer agents. The catalytic and biological properties of these complexes largely depend on the nature of the bridging carboxylate ligands. Trifluoroacetate (tfa)-containing dirhodium compounds have been used to build artificial metalloenzymes upon reaction with peptides and have been shown to be more cytotoxic than dirhodium tetraacetate. However, there is no structural information on the interaction between these compounds and proteins. Here, cis-Rh2(μ-O2CCH3)2(μ-O2CCF3)2 ([cis-Rh2(OAc)2(tfa)2]) has been synthesized and its reaction with bovine pancreatic ribonuclease (RNase A) and hen egg white lysozyme (HEWL) was analyzed using a combination of different techniques, including Fluorine-19 nuclear magnetic resonance spectroscopy and macromolecular X-ray crystallography, with the aim to unveil the differences in the reactivity of tfa-containing dihrodium complexes with proteins when compared to [Rh2(OAc)4]. [cis-Rh2(OAc)2(tfa)2] and [Rh2(OAc)4] bind the N atoms of His side chains of RNase A at the axial position; however the fluorine-containing compound rapidly loses its tfa ligands, while [Rh2(OAc)4] can retain the acetate ligands upon protein binding. The reactivity of [cis-Rh2(OAc)2(tfa)2] with HEWL is slightly distinct when compared to that of [Rh2(OAc)4] under the same experimental conditions; however, both [cis-Rh2(OAc)2(tfa)2] and [Rh2(OAc)4] degrade when soaked within HEWL crystals. These results provide a structural-based guide for the design of new heterogenous chiral dirhodium/peptide and dirhodium/protein adducts with application in the fields of organic synthesis and asymmetric catalysis.
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Affiliation(s)
- Domenico Loreto
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, via Cinthia 21, 80126 Naples, Italy.
| | - Anna Esposito
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le V. Tecchio 80, 80125 Naples, Italy
| | - Nicola Demitri
- Elettra-Sincrotrone Trieste, S.S. 14 km 163.5 in Area Science Park, 34149 Trieste, Italy
| | - Annalisa Guaragna
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, P.le V. Tecchio 80, 80125 Naples, Italy
| | - Antonello Merlino
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, via Cinthia 21, 80126 Naples, Italy.
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