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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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2
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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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Chen Z, Shimabukuro K, Bacsa J, Musaev DG, Davies HML. D 4-Symmetric Dirhodium Tetrakis(binaphthylphosphate) Catalysts for Enantioselective Functionalization of Unactivated C-H Bonds. J Am Chem Soc 2024; 146:19460-19473. [PMID: 38959398 PMCID: PMC11258696 DOI: 10.1021/jacs.4c06023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 06/09/2024] [Accepted: 06/11/2024] [Indexed: 07/05/2024]
Abstract
Dirhodium tetrakis(2,2'-binaphthylphosphate) catalysts were successfully developed for asymmetric C-H functionalization with trichloroethyl aryldiazoacetates as the carbene precursors. The 2,2'-binaphthylphosphate (BNP) ligands were modified by introduction of aryl and/or chloro functionality at the 4,4',6,6' positions. As the BNP ligands are C2-symmetric, the resulting dirhodium tetrakis(2,2'-binaphthylphosphate) complexes were expected to be D4-symmetric, but X-ray crystallographic and computational studies revealed this is not always the case because of internal T-shaped CH-π and aryl-aryl interactions between the ligands. The optimum catalyst is Rh2(S-megaBNP)4, with 3,5-di(tert-butyl)phenyl substituents at the 4,4' positions and chloro substituents at the 6,6' positions. This catalyst adopts a D4-symmetric arrangement and is ideally suited for site-selective C-H functionalization at unactivated tertiary sites with high levels of enantioselectivity, outperforming the best dirhodium tetracarboxylate catalyst developed for this reaction. The standard reactions were conducted with a catalyst loading of 1 mol % but lower catalyst loadings can be used if desired, as illustrated in the C-H functionalization of cyclohexane in 91% ee with 0.0025 mol % catalyst loading (29,400 turnover numbers). These studies further illustrate the effectiveness of donor/acceptor carbenes in site-selective intermolecular C-H functionalization and expand the toolbox of catalysts available for catalyst-controlled C-H functionalization.
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Affiliation(s)
- Ziyi Chen
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Kristin Shimabukuro
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - John Bacsa
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Djamaladdin G. Musaev
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Cherry
L. Emerson Center for Scientific Computation, Emory University, 1521
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Huw M. L. Davies
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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Nguyen TT, Navarro A, Ruble JC, Davies HML. Stereoselective Synthesis of Either Exo- or Endo-3-Azabicyclo[3.1.0]hexane-6-carboxylates by Dirhodium(II)-Catalyzed Cyclopropanation with Ethyl Diazoacetate under Low Catalyst Loadings. Org Lett 2024; 26:2832-2836. [PMID: 38166395 PMCID: PMC11020159 DOI: 10.1021/acs.orglett.3c03652] [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: 12/01/2023] [Accepted: 12/01/2023] [Indexed: 01/04/2024]
Abstract
Although cyclopropanation with donor/acceptor carbenes can be conducted under low catalyst loadings (<0.001 mol %), such low loading has not been generally effective for other classes of carbenes such as acceptor carbenes. In this current study, we demonstrate that ethyl diazoacetate can be effectively used in the cyclopropanation of N-Boc-2,5-dihydropyrrole with dirhodium(II) catalyst loadings of 0.005 mol %. By appropriate choice of catalyst and hydrolysis conditions, either the exo- or endo-3-azabicyclo[3.1.0]hexanes can be formed cleanly with high levels of diastereoselectivity with no chromatographic purification.
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Affiliation(s)
| | - Antonio Navarro
- Lilly
Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - J. Craig Ruble
- Lilly
Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Huw M. L. Davies
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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Lennon G, Dingwall P. Enabling High Throughput Kinetic Experimentation by Using Flow as a Differential Kinetic Technique. Angew Chem Int Ed Engl 2024; 63:e202318146. [PMID: 38078481 PMCID: PMC10952970 DOI: 10.1002/anie.202318146] [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: 11/27/2023] [Indexed: 12/23/2023]
Abstract
Kinetic data is most commonly collected through the generation of time-series data under either batch or flow conditions. Existing methods to generate kinetic data in flow collect integral data (concentration over time) only. Here, we report a method for the rapid and direct collection of differential kinetic data (direct measurement of rate) in flow by performing a series of instantaneous rate measurements on sequential small-scale reactions. This technique decouples the time required to generate a full kinetic profile from the time required for a reaction to reach completion, enabling high throughput kinetic experimentation. In addition, comparison of kinetic profiles constructed at different residence times allows the robustness, or stability, of homogeneously catalysed reactions to be interrogated. This approach makes use of a segmented flow platform which was shown to quantitatively reproduce batch kinetic data. The proline mediated aldol reaction was chosen as a model reaction to perform a high throughput kinetic screen of 216 kinetic profiles in 90 hours, one every 25 minutes, which would have taken an estimated continuous 3500 hours in batch, an almost 40-fold increase in experimental throughput matched by a corresponding reduction in material consumption.
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Affiliation(s)
- Gavin Lennon
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
| | - Paul Dingwall
- School of Chemistry and Chemical EngineeringQueen's University BelfastDavid Keir Building, Stranmillis RoadBelfastBT9 5AGUK
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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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Sailer J, Sharland JC, Bacsa J, Harris CF, Berry JF, Musaev DG, Davies HML. Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates. Organometallics 2023; 42:2122-2133. [PMID: 37592951 PMCID: PMC10428512 DOI: 10.1021/acs.organomet.3c00268] [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: 06/09/2023] [Indexed: 08/19/2023]
Abstract
A series of chiral bowl-shaped diruthenium(II,III) tetracarboxylate catalysts were prepared and evaluated in asymmetric cyclopropanations with donor/acceptor carbenes derived from aryldiazoacetates. The diruthenium catalysts self-assembled to generate C4-symmetric bowl-shaped structures in an analogous manner to their dirhodium counterparts. The optimum catalyst was found to be Ru2(S-TPPTTL)4·BArF [S-TPPTTL = (S)-2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate, BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate], which resulted in the cyclopropanation of a range of substrates in up to 94% ee. Synthesis and evaluation of first-row transition-metal congeners [Cu(II/II) and Co(II/II)] invariably resulted in catalysts that afforded little to no asymmetric induction. Computational studies indicate that the carbene complexes of these dicopper and dicobalt complexes, unlike the dirhodium and diruthenium systems, are prone to the loss of carboxylate ligands, which would destroy the bowl-shaped structure critical for asymmetric induction.
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Affiliation(s)
- Joshua
K. Sailer
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Jack C. Sharland
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - John Bacsa
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Caleb F. Harris
- Department
of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - John F. Berry
- Department
of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Djamaladdin G. Musaev
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Cherry
L. Emerson Center for Scientific Computation, Emory University, 1521
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Huw M. L. Davies
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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