1
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Ives RA, Maturi W, Gill MT, Rankine C, McGonigal PR. A guide to bullvalene stereodynamics. Chem Sci 2024:d4sc03700f. [PMID: 39220163 PMCID: PMC11358867 DOI: 10.1039/d4sc03700f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
Here, we analyze the stereodynamic properties of bullvalenes using principal moments of inertia and exit vector plots to draw comparisons with commonly used ring systems in medicinal chemistry. To aid analyses, we first classify (i) the four elementary rearrangement steps available to substituted bullvalenes, which (ii) can be described by applying positional descriptors (α, β, γ, and δ) to the substituents. We also (iii) derive an intuitive equation to calculate the number of isomers for a given bullvalene system. Using DFT-modelled structures for di-, tri-, and tetrasubstituted bullvalenes, generated using a newly developed computational tool (bullviso), we show that their 3D shapes and the exit vectors available from the bullvalene scaffold make them comparable to other bioisosteres currently used to replace planar aromatic ring systems in drug discovery. Unlike conventional ring systems, the shapeshifting valence isomerism of bullvalenes gives rise to numerous shapes and substituent relationships attainable as a concentration-independent dynamic covalent library from a single compound. We visualize this property by applying population weightings to the principal moments of inertia and exit vector analyses to reflect the relative thermodynamic stabilities of the available isomers.
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Affiliation(s)
- Robert A Ives
- Department of Chemistry, University of York Heslington York YO10 5DD UK
- Department of Chemistry, Durham University Lower Mountjoy, Stockton Road Durham DH1 3LE UK
| | - William Maturi
- Department of Chemistry, University of York Heslington York YO10 5DD UK
- Department of Chemistry, Durham University Lower Mountjoy, Stockton Road Durham DH1 3LE UK
| | - Matthew T Gill
- Department of Chemistry, University of York Heslington York YO10 5DD UK
| | - Conor Rankine
- Department of Chemistry, University of York Heslington York YO10 5DD UK
| | - Paul R McGonigal
- Department of Chemistry, University of York Heslington York YO10 5DD UK
- Department of Chemistry, Durham University Lower Mountjoy, Stockton Road Durham DH1 3LE UK
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2
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Sun PB, Pomfret MN, Elardo MJ, Suresh A, Rentería-Gómez Á, Lalisse RF, Keating S, Chen C, Hilburg SL, Chakma P, Wu Y, Bell RC, Rowan SJ, Gutierrez O, Golder MR. Molecular Ball Joints: Mechanochemical Perturbation of Bullvalene Hardy-Cope Rearrangements in Polymer Networks. J Am Chem Soc 2024; 146:19229-19238. [PMID: 38961828 DOI: 10.1021/jacs.4c04401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The solution-state fluxional behavior of bullvalene has fascinated physical organic and supramolecular chemists alike. Little effort, however, has been put into investigating bullvalene applications in bulk, partially due to difficulties in characterizing such dynamic systems. To address this knowledge gap, we herein probe whether bullvalene Hardy-Cope rearrangements can be mechanically perturbed in bulk polymer networks. We use dynamic mechanical analysis to demonstrate that the activation barrier to the glass transition process is significantly elevated for bullvalene-containing materials relative to "static" control networks. Furthermore, bullvalene rearrangements can be mechanically perturbed at low temperatures in the glassy region; such behavior facilitates energy dissipation (i.e., increased hysteresis energy) and polymer chain alignment to stiffen the material (i.e., increased Young's modulus) under load. Computational simulations corroborate our work that showcases bullvalene as a reversible "low-force" covalent mechanophore in the modulation of viscoelastic behavior.
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Affiliation(s)
- Peiguan B Sun
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Meredith N Pomfret
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Matthew J Elardo
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Adhya Suresh
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Ángel Rentería-Gómez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Remy F Lalisse
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Sheila Keating
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Chuqiao Chen
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Shayna L Hilburg
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98115, United States
| | - Progyateg Chakma
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Yunze Wu
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Rowina C Bell
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
| | - Stuart J Rowan
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
- Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Matthew R Golder
- Department of Chemistry and Molecular Engineering & Science Institute, University of Washington, Seattle, Washington 98115, United States
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3
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Sanchez A, Gonzalez VM, Sakamoto J, Gurajapu A, Maimone TJ. Modular, Enantioselective Entry into Polysubstituted Shapeshifting Molecules. J Am Chem Soc 2024; 146:17573-17579. [PMID: 38901002 DOI: 10.1021/jacs.4c03323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Dynamic, shapeshifting hydrocarbons have emerged as enabling frameworks across drug discovery, materials science, and catalysis. Their employment, however, is often hampered by a lack of efficient synthetic methods for their preparation. Herein, we report a unified, concise, and modular synthesis of enantioenriched shapeshifting hydrocarbons (barbaralones and bullvalones) and multisubstituted bullvalenes, leveraging mild photochemical and base-induced rearrangements.
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Affiliation(s)
- Andre Sanchez
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California, 94720, United States
| | - Vanessa M Gonzalez
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California, 94720, United States
| | - Jukiya Sakamoto
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California, 94720, United States
| | - Anjali Gurajapu
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California, 94720, United States
| | - Thomas J Maimone
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California, 94720, United States
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4
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Dohmen C, Paululat T, Ihmels H. Reversible Restrain and Release of the Dynamic Valence Isomerization in a Shape-shifting Bullvalene by Complex Formation. Chemistry 2024; 30:e202304311. [PMID: 38275100 DOI: 10.1002/chem.202304311] [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: 12/24/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/27/2024]
Abstract
In search for structural features that enable the control of the valence isomerization of the fluxional bullvalene, a bullvalene-bis(harmane) conjugate is identified that acts as chelating ligand in complexes with metal ions. Spectrometric titrations show that this ligand forms 1 : 1 complexes with Ag+, Cu+, Cu2+, and Zn2+. Most importantly, detailed NMR-spectroscopic analysis at different temperatures reveals that the complexation with Ag+ strongly affects the dynamic isomerization of the bullvalene unit of the ligand such that only one predominant valence isomer is formed, even at 5 °C. Detailed 1H-NMR-spectroscopic studies disclose an increased barrier (~11 kJ mol-1) of the Cope rearrangement. Furthermore, the addition of hexacyclene displaces the Ag+ from the complex, so that the valence isomerization is accelerated and an equilibrium with two predominant isomers is formed. In turn, repeated addition of Ag+ regains the complex with the restrained isomerization of the bullvalene unit. This method to control the valence isomerism by straightforward chemical stimuli may be used to simplify structural analysis at elevated temperatures, i. e. a feature not available so far with bullvalenes, and it may be employed as functional element in dynamic supramolecular assemblies.
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Affiliation(s)
- Christoph Dohmen
- Department of Chemistry-Biology, and Center of Micro-and Nanochemistry and (Bio)Technology (Cμ), University of Siegen, Adolf-Reichwein-Str. 2, 57068, Siegen, Germany
| | - Thomas Paululat
- Department of Chemistry-Biology, and Center of Micro-and Nanochemistry and (Bio)Technology (Cμ), University of Siegen, Adolf-Reichwein-Str. 2, 57068, Siegen, Germany
| | - Heiko Ihmels
- Department of Chemistry-Biology, and Center of Micro-and Nanochemistry and (Bio)Technology (Cμ), University of Siegen, Adolf-Reichwein-Str. 2, 57068, Siegen, Germany
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5
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Nédellec T, Boitrel B, Le Gac S. Parallel Chirality Inductions in Möbius Zn(II) Hexaphyrin Transformation Networks. J Am Chem Soc 2023. [PMID: 38037277 DOI: 10.1021/jacs.3c10835] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Networked chemical transformations are key features of biological systems, in which complex multicomponent interactions enable the emergence of sophisticated functions. Being interested in chirality induction phenomena with dynamic Möbius π-systems, we have designed a pair of Möbius [28]hexaphyrin ligands in order to investigate mixtures rather than isolated molecules. Thus, a hexaphyrin bearing a chiral amino arm was first optimized and found to bind a ZnOAc moiety, triggering an impressive quasi-quantitative chirality induction over the Möbius π-system. Second, this amino-type hexaphyrin was mixed with a second hexaphyrin bearing a chiral carboxylate arm, affording at first ill-defined coordination assemblies in the presence of zinc. In contrast, a social self-sorting behavior occurred upon the addition of two exogenous achiral effectors (AcO- and BuNH2), leading to a well-defined 1:1 mixture of two Möbius complexes featuring a sole Möbius twist configuration (parallel chirality inductions). We next successfully achieved compartmentalized switching, i.e., a single-component transformation from such a complex mixture. The BuNH2 effector was selectively protected with Boc2O, owing to a lower reactivity of the arm's NH2 function intramolecularly bound to zinc, and subsequent addition of BuNH2 restored the initial mixture, retaining parallel chirality inductions (five cycles). By changing the nature and twist configuration of only one of the two complexes, at initial state or by switching, this approach enables a "two-channel" tuning of the chiroptical properties of the ensemble. Such multiple dynamic chirality inductions, controlled by selective metal-ligand recognition and chemical reactivity, set down the basis for Möbius-type stereoselective transformation networks with new functions.
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Affiliation(s)
- Thomas Nédellec
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000 Rennes, France
| | - Bernard Boitrel
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000 Rennes, France
| | - Stéphane Le Gac
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000 Rennes, France
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6
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Laconsay CJ, Tantillo DJ. Modulating Escape Channels of Cycloheptatrienyl Rhodium Carbenes To Form Semibullvalene. J Org Chem 2023. [PMID: 37335974 DOI: 10.1021/acs.joc.3c00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
We describe the various escape channels available to dirhodium carbene intermediates from cycloheptatrienyl diazo compounds located with density functional theory. An intramolecular cyclopropanation would, in principle, provide a new route to semibullvalenes (SBVs). A detailed exploration of the potential energy surface reveals that methylating carbon-7 suppresses a competing β-hydride migration pathway to heptafulvene products, giving SBV formation a reasonable chance. During our explorations, we additionally discovered unusual spirononatriene, spironorcaradiene, and metal-stabilized 9-barbaralyl cation structures as local minima.
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Affiliation(s)
- Croix J Laconsay
- Department of Chemistry, University of California─Davis, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California─Davis, Davis, California 95616, United States
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7
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Sanchez A, Gurajapu A, Guo W, Kong WY, Laconsay CJ, Settineri NS, Tantillo DJ, Maimone TJ. A Shapeshifting Roadmap for Polycyclic Skeletal Evolution. J Am Chem Soc 2023. [PMID: 37279177 DOI: 10.1021/jacs.3c03960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Polycyclic ring systems are ubiquitous three-dimensional (3D) structural motifs central to the function of many biologically active small molecules and organic materials. Indeed, subtle changes to the overall molecular shape and connectivity of atoms in a polycyclic framework (i.e., isomerism) can drastically alter its function and properties. Unfortunately, direct evaluation of these structure-function relationships typically requires the development of distinct synthetic strategies toward a specific isomer. Dynamic, "shapeshifting" carbon cages present a promising approach for sampling isomeric chemical space but are often difficult to control and are largely limited to thermodynamic mixtures of positional isomers about a single core scaffold. Here, we describe the development of a new shapeshifting C9-chemotype and a chemical blueprint for its evolution into structurally and energetically diverse isomeric ring systems. By leveraging the unique molecular topology of π-orbitals interacting through-space (homoconjugation), a common skeletal ancestor evolved into a complex network of valence isomers. This unusual system represents an exceedingly rare small molecule capable of undergoing controllable and continuous isomerization processes through the iterative use of just two chemical steps (light and organic base). Computational and photophysical studies of the isomer network provide fundamental insight into the reactivity, mechanism, and role of homoconjugative interactions. Importantly, these insights may inform the rational design and synthesis of new dynamic, shapeshifting systems. We anticipate this process could be a powerful tool for the synthesis of structurally diverse, isomeric polycycles central to many bioactive small molecules and functional organic materials.
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Affiliation(s)
- Andre Sanchez
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Anjali Gurajapu
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Wentao Guo
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Wang-Yeuk Kong
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Croix J Laconsay
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Nicholas S Settineri
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
| | - Thomas J Maimone
- Department of Chemistry, University of California-Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
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8
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Bismillah AN, Johnson TG, Hussein BA, Turley AT, Saha PK, Wong HC, Aguilar JA, Yufit DS, McGonigal PR. Control of dynamic sp 3-C stereochemistry. Nat Chem 2023; 15:615-624. [PMID: 36914791 PMCID: PMC10159849 DOI: 10.1038/s41557-023-01156-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 02/09/2023] [Indexed: 03/16/2023]
Abstract
Stereogenic sp3-hybridized carbon centres are fundamental building blocks of chiral molecules. Unlike dynamic stereogenic motifs, such as sp3-nitrogen centres or atropisomeric biaryls, sp3-carbon centres are usually fixed, requiring intermolecular reactions to undergo configurational changes. Here we report the internal enantiomerization of fluxional carbon cages and the consequences of their adaptive configurations for the transmission of stereochemical information. The sp3-carbon stereochemistry of the rigid tricyclic cages is inverted through strain-assisted Cope rearrangements, emulating the low-barrier configurational dynamics typical for sp3-nitrogen inversion or conformational isomerism. This dynamic enantiomerization can be stopped, restarted or slowed by external reagents, while the configuration of the cage is controlled by neighbouring, fixed stereogenic centres. As part of a phosphoramidite-olefin ligand, the fluxional cage acts as a conduit to transmit stereochemical information from the ligand while also transferring its dynamic properties to chiral-at-metal coordination environments, influencing catalysis, ion pairing and ligand exchange energetics.
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Affiliation(s)
| | | | | | | | | | - Ho Chi Wong
- Department of Chemistry, Durham University, Durham, UK
| | | | | | - Paul R McGonigal
- Department of Chemistry, Durham University, Durham, UK. .,Department of Chemistry, University of York, York, UK.
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9
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Shape-shifters among water clusters. Struct Chem 2022. [DOI: 10.1007/s11224-022-02107-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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10
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Hsu HY, Ou JT, Cheng TT, Lin HY, Lin CY, Chen J, Sun B, Chung PW, Wang CL. Connecting Molecular and Supramolecular Shapeshifting by the Ostwald's Nucleation Stages of a Star Giant Molecule. J Am Chem Soc 2022; 144:9390-9398. [PMID: 35587710 DOI: 10.1021/jacs.2c01715] [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
The shapeshifting behavior for synthetic matters was found at either the molecular or supramolecular level, but the connection between shapeshifting at the two hierarchical levels remains missing. In this study, an 8-arm star giant molecule, NPOSS, was synthesized to connect the molecular and supramolecular shapeshifting. Controlling the conditions of bulk self-assembly allowed us to bring NPOSS into three different Ostwald's stages of nucleation. The high conformational flexibility of NPOSS facilitates molecular shapeshifting and allows NPOSS to take the discotic, rod-like and star-like geometries in different Ostwald's stages. Simultaneous changes in the supramolecular scaffolds were observed as the discotic, rod-like and star-like NPOSS molecules self-assembled into the supramolecular scaffolds of 1D columns, 2D lamellae, and 3D networks, respectively. These changes in the hierarchical structures also affect the CO2 affinity of NPOSS. Therefore, the connection between the molecular/supramolecular shapeshifting and the structure-driven property changes of NPOSS were established by taking advantage of the high conformational freedom of the 8-arm star giant molecule and its diverse self-assembly pathways leading to the different Ostwald's stages.
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Affiliation(s)
- Hong-Yu Hsu
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Jou-Tsen Ou
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Tsu-Tung Cheng
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Heng-Yi Lin
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Chan-Yi Lin
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Jia Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China
| | - Bin Sun
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China
| | - Po-Wen Chung
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan.,Department of Chemistry, National Sun Yat-Sen University, Kaohsiung City 80424, Taiwan
| | - Chien-Lung Wang
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
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11
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Sanz‐Novo M, Mato M, León Í, Echavarren AM, Alonso JL. Shape‐Shifting Molecules: Unveiling the Valence Tautomerism Phenomena in Bare Barbaralones. Angew Chem Int Ed Engl 2022; 61:e202117045. [PMID: 35165988 PMCID: PMC9311078 DOI: 10.1002/anie.202117045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Indexed: 12/28/2022]
Abstract
We report a state‐of‐the‐art spectroscopic study of an archetypical barbaralone, conclusively revealing the valence tautomerism phenomena for this bistable molecular system. The two distinct 1‐ and 5‐substituted valence tautomers have been isolated in a supersonic expansion for the first time and successfully characterized by high‐resolution rotational spectroscopy. This work provides irrefutable experimental evidence of the [3,3]‐rearrangement in barbaralones and highlights the use of rotational spectroscopy to analyze shape‐shifting mixtures. Moreover, this observation opens the window toward the characterization of new fluxional systems in the isolation conditions of the gas phase and should serve as a reference point in the general understanding of valence tautomerism.
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Affiliation(s)
- Miguel Sanz‐Novo
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
| | - Mauro Mato
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Av. Països Catalans 16 43007 Tarragona Spain
- Departament de Química Analítica i Química Orgànica Universitat Rovira i Virgili C/Marcel⋅li Domingo s/n 43007 Tarragona Spain
| | - Íker León
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
| | - Antonio M. Echavarren
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Av. Països Catalans 16 43007 Tarragona Spain
- Departament de Química Analítica i Química Orgànica Universitat Rovira i Virgili C/Marcel⋅li Domingo s/n 43007 Tarragona Spain
| | - José L. Alonso
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
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12
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Sanchez A, Maimone TJ. Taming Shapeshifting Anions: Total Synthesis of Ocellatusone C. J Am Chem Soc 2022; 144:7594-7599. [PMID: 35420799 DOI: 10.1021/jacs.2c02627] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Guided by a synthetic design aimed at late-stage diversification, we report the preparation of unusual shapeshifting anions and their subsequent application to the total synthesis of the polyketide natural product ocellatusone C. Site-selective core functionalization of a readily accessible bicyclo[3.3.1]nonane architecture sets the stage for shape-selective side chain installation via a nonfluxional π-allyl Pd-complex derived from a barbaralyl-type anion. Several interesting chemical findings, including substituent-dependent bridged bicycloisomerism and the isolation of a stabilized, 3° carbon-bound Pd-ketone enolate complex, are reported.
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Affiliation(s)
- Andre Sanchez
- Department of Chemistry, University of California─Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
| | - Thomas J Maimone
- Department of Chemistry, University of California─Berkeley, 826 Latimer Hall, Berkeley, California 94720, United States
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13
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Sanz‐Novo M, Mato M, León Í, Echavarren AM, Alonso JL. Shape‐Shifting Molecules: Unveiling the Valence Tautomerism Phenomena in Bare Barbaralones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202117045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Miguel Sanz‐Novo
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
| | - Mauro Mato
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Av. Països Catalans 16 43007 Tarragona Spain
- Departament de Química Analítica i Química Orgànica Universitat Rovira i Virgili C/Marcel⋅li Domingo s/n 43007 Tarragona Spain
| | - Íker León
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
| | - Antonio M. Echavarren
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Av. Països Catalans 16 43007 Tarragona Spain
- Departament de Química Analítica i Química Orgànica Universitat Rovira i Virgili C/Marcel⋅li Domingo s/n 43007 Tarragona Spain
| | - José L. Alonso
- Grupo de Espectroscopía Molecular (GEM) Edificio Quifima Área de Química-Física Laboratorios de Espectroscopía y Bioespectroscopía Parque Científico UVa Unidad Asociada CSIC Universidad de Valladolid 47011 Valladolid Spain
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14
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Birvé AP, Patel HD, Price JR, Bloch WM, Fallon T. Guest-Dependent Isomer Convergence of a Permanently Fluxional Coordination Cage. Angew Chem Int Ed Engl 2022; 61:e202115468. [PMID: 34854191 PMCID: PMC9303423 DOI: 10.1002/anie.202115468] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Indexed: 11/09/2022]
Abstract
A fluxional bis-monodentate ligand, based on the archetypal shape-shifting molecule bullvalene, self-assembles with M2+ (M=Pd2+ or Pt2+ ) to produce a highly complex ensemble of permanently fluxional coordination cages. Metal-mediated self-assembly selects for an M2 L4 architecture while maintaining shape-shifting ligand complexity. A second level of simplification is achieved with guest-exchange; the binding of halides within the M2 L4 cage mixture results in a convergence to a cage species with all four ligands present as the "B isomer". Within this confine, the reaction graph of the bullvalene is greatly restricted, but gives rise to a mixture of 38 possible diastereoisomers in rapid exchange. X-ray crystallography reveals a preference for an achiral form consisting of both ligand enantiomers. Through a combination of NMR spectroscopy and DFT calculations, we elucidate the restricted isomerisation pathway of the permanently fluxional M2 L4 assembly.
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Affiliation(s)
- André P. Birvé
- Department of ChemistryUniversity of AdelaideAdelaide5005Australia
| | - Harshal D. Patel
- Department of ChemistryUniversity of AdelaideAdelaide5005Australia
| | - Jason R. Price
- ANSTOAustralian Synchrotron800 Blackburn RoadClaytonVic 3168Australia
| | - Witold M. Bloch
- Department of ChemistryUniversity of AdelaideAdelaide5005Australia
| | - Thomas Fallon
- Department of ChemistryUniversity of AdelaideAdelaide5005Australia
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Birvé AP, Patel HD, Price JR, Bloch WM, Fallon T. Guest‐Dependent Isomer Convergence of a Permanently Fluxional Coordination Cage. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- André P. Birvé
- Department of Chemistry University of Adelaide Adelaide 5005 Australia
| | - Harshal D. Patel
- Department of Chemistry University of Adelaide Adelaide 5005 Australia
| | - Jason R. Price
- ANSTO Australian Synchrotron 800 Blackburn Road Clayton Vic 3168 Australia
| | - Witold M. Bloch
- Department of Chemistry University of Adelaide Adelaide 5005 Australia
| | - Thomas Fallon
- Department of Chemistry University of Adelaide Adelaide 5005 Australia
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Shapeshifting radicals. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2021.111373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Patel HD, Gaggl S, Pašteka LF, Fallon T. Ambimodal Pericyclic Rearrangements of Dialkenyl-Bullvalenes Give Tetrahydro-1,8-ethenoheptalenes. Org Lett 2021; 24:319-323. [PMID: 34898219 DOI: 10.1021/acs.orglett.1c03984] [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
The fluxional structure of bullvalene is expanded by the discovery of a [5,5]-sigmatropic rearrangement of dialkenyl substituted derivatives. This gives rise to tetrahydro-1,8-ethenoheptalenes (THEH), representing the first examples of this tricyclic scaffold. Variation of the substitution pattern alters the product distribution, including one thermodynamically balanced between THEH and bullvalene isomers. DFT calculations are used to explore the thermodynamic landscape and reaction mechanism revealing a pretransition state bifurcation leading to a concerted ambimodal rearrangement pathway.
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Affiliation(s)
- Harshal D Patel
- Department of Chemistry, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Sebastian Gaggl
- Department of Chemistry, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Lukáš F Pašteka
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, 842 15 Bratislava, Slovakia
| | - Thomas Fallon
- Department of Chemistry, The University of Adelaide, Adelaide, SA 5005, Australia
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Kozuch S, Schleif T, Karton A. Quantum mechanical tunnelling: the missing term to achieve sub-kJ mol -1 barrier heights. Phys Chem Chem Phys 2021; 23:10888-10898. [PMID: 33908522 DOI: 10.1039/d1cp01275d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
To predict barrier heights at low temperatures, it is not enough to employ highly accurate electronic structure methods. We discuss the influence of quantum tunnelling on the comparison of experimental and theoretical activation parameters (Ea, ΔH‡, ΔG‡, or ΔS‡), since the slope-based experimental techniques to obtain them completely neglect the tunnelling component. The intramolecular degenerate rearrangement of four fluxional molecules (bullvalene, barbaralane, semibullvalene, and norbornadienylidene) were considered, systems that cover the range between fast deep tunneling and small but significant shallow tunnelling correction. The barriers were computed with the composite W3lite-F12 method at the CCSDT(Q)/CBS level, and the tunnelling contribution with small curvature tunnelling. While at room temperature the effect is small (∼1 kJ mol-1), at low temperatures it can be considerable (in the order of tens of kJ mol-1 at ∼80 K).
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Affiliation(s)
- Sebastian Kozuch
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, 841051, Israel.
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Laconsay CJ, Mallick D, Shaik S. External Electric Fields Interrupt the Concerted Cope Rearrangement of Semibullvalene. J Org Chem 2020; 86:731-738. [PMID: 33280381 DOI: 10.1021/acs.joc.0c02322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The topic of this paper is whether the mechanism of the degenerate Cope rearrangement of semibullvalene can be affected by the presence of electrostatic fields. Herein, we report that the shape of the energy surface, as demonstrated by an "interrupted" (stepwise) mechanism, is altered in the presence of a copper cation, Cu+. Natural bond-orbital and block-localized wave-function energy decomposition analyses suggest that orbital and electrostatic interactions play a major role in altering the shape of the energy surface. Applying additional external electric fields (EEFs) induces a significant change to the energy surface with Cu+ present but negligible effects in the absence of Cu+. These findings are consistent with recent studies that demonstrate that EEFs more readily stabilize/destabilize systems with larger, more polarizable, dipole moments.
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Affiliation(s)
- Croix J Laconsay
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.,Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, California 95616, United States
| | - Dibyendu Mallick
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.,Department of Chemistry, Presidency University, Kolkata 700073, India
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.138018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Vayer M, Bour C, Gandon V. Exploring the Versatility of 7‐Alkynylcycloheptatriene Scaffolds Under π‐Acid Catalysis. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Marie Vayer
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR 8182 Université Paris‐Saclay Bâtiment 420 91405 Orsay cedex France
| | - Christophe Bour
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR 8182 Université Paris‐Saclay Bâtiment 420 91405 Orsay cedex France
| | - Vincent Gandon
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) CNRS UMR 8182 Université Paris‐Saclay Bâtiment 420 91405 Orsay cedex France
- Laboratoire de Chimie Moléculaire (LCM) CNRS UMR 9168, Ecole Polytechnique Institut Polytechnique de Paris route de Saclay 91128 Palaiseau cedex France
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