1
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Clover A, Jones AP, Berger RF, Kaminsky W, O’Neil GW. Regioselective Fluorohydrin Synthesis from Allylsilanes and Evidence for a Silicon-Fluorine Gauche Effect. J Org Chem 2024; 89:4309-4318. [PMID: 38457664 PMCID: PMC11002936 DOI: 10.1021/acs.joc.3c02163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 03/10/2024]
Abstract
Allylsilanes can be regioselectively transformed into the corresponding 3-silylfluorohydrin in good yield using a sequence of epoxidation followed by treatment with HF·Et3N with or without isolation of the intermediate epoxide. Various silicon-substitutions are tolerated, resulting in a range of 2-fluoro-3-silylpropan-1-ol products from this method. Whereas other fluorohydrin syntheses by epoxide opening using HF·Et3N generally require more forcing conditions (e.g., higher reaction temperature), opening of allylsilane-derived epoxides with this reagent occurs at room temperature. We attribute this rate acceleration along with the observed regioselectivity to a β-silyl effect that stabilizes a proposed cationic intermediate. The use of enantioenriched epoxides indicates that both SN1- and SN2-type mechanisms may be operable depending on substitution at silicon. Conformational analysis by NMR and theory along with a crystal structure obtained by X-ray diffraction points to a preference for silicon and fluorine to be proximal to one another in the products, perhaps favored due to electrostatic interactions.
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Affiliation(s)
- Alexie
W. Clover
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Adam P. Jones
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Robert F. Berger
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Werner Kaminsky
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Gregory. W. O’Neil
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
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2
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Stylianakis I, Zervos N, Lii JH, Pantazis DA, Kolocouris A. Conformational energies of reference organic molecules: benchmarking of common efficient computational methods against coupled cluster theory. J Comput Aided Mol Des 2023; 37:607-656. [PMID: 37597063 PMCID: PMC10618395 DOI: 10.1007/s10822-023-00513-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/03/2023] [Indexed: 08/21/2023]
Abstract
We selected 145 reference organic molecules that include model fragments used in computer-aided drug design. We calculated 158 conformational energies and barriers using force fields, with wide applicability in commercial and free softwares and extensive application on the calculation of conformational energies of organic molecules, e.g. the UFF and DREIDING force fields, the Allinger's force fields MM3-96, MM3-00, MM4-8, the MM2-91 clones MMX and MM+, the MMFF94 force field, MM4, ab initio Hartree-Fock (HF) theory with different basis sets, the standard density functional theory B3LYP, the second-order post-HF MP2 theory and the Domain-based Local Pair Natural Orbital Coupled Cluster DLPNO-CCSD(T) theory, with the latter used for accurate reference values. The data set of the organic molecules includes hydrocarbons, haloalkanes, conjugated compounds, and oxygen-, nitrogen-, phosphorus- and sulphur-containing compounds. We reviewed in detail the conformational aspects of these model organic molecules providing the current understanding of the steric and electronic factors that determine the stability of low energy conformers and the literature including previous experimental observations and calculated findings. While progress on the computer hardware allows the calculations of thousands of conformations for later use in drug design projects, this study is an update from previous classical studies that used, as reference values, experimental ones using a variety of methods and different environments. The lowest mean error against the DLPNO-CCSD(T) reference was calculated for MP2 (0.35 kcal mol-1), followed by B3LYP (0.69 kcal mol-1) and the HF theories (0.81-1.0 kcal mol-1). As regards the force fields, the lowest errors were observed for the Allinger's force fields MM3-00 (1.28 kcal mol-1), ΜΜ3-96 (1.40 kcal mol-1) and the Halgren's MMFF94 force field (1.30 kcal mol-1) and then for the MM2-91 clones MMX (1.77 kcal mol-1) and MM+ (2.01 kcal mol-1) and MM4 (2.05 kcal mol-1). The DREIDING (3.63 kcal mol-1) and UFF (3.77 kcal mol-1) force fields have the lowest performance. These model organic molecules we used are often present as fragments in drug-like molecules. The values calculated using DLPNO-CCSD(T) make up a valuable data set for further comparisons and for improved force field parameterization.
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Affiliation(s)
- Ioannis Stylianakis
- Department of Medicinal Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, 15771, Athens, Greece
| | - Nikolaos Zervos
- Department of Medicinal Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, 15771, Athens, Greece
| | - Jenn-Huei Lii
- Department of Chemistry, National Changhua University of Education, Changhua City, Taiwan
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Antonios Kolocouris
- Department of Medicinal Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, 15771, Athens, Greece.
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771, Athens, Greece.
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3
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Emenike BU, Farshadmand A, Zeller M, Roman AJ, Sevimler A, Shinn DW. Electrostatic CH-π Interactions Can Override Fluorine Gauche Effects To Exert Conformational Control. Chemistry 2023; 29:e202203139. [PMID: 36286329 DOI: 10.1002/chem.202203139] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Indexed: 11/07/2022]
Abstract
Fluorine gauche effects are conformational properties of 2-fluoroethanes often applied in modern molecular designs. However, the physical origins of fluorine gauche effects are not well understood, with the consensus favoring the established hyperconjugation theory over an emerging electrostatic model. Using a series of model systems, we show that a shift to fluorine gauche effects can be influenced by intramolecular CH⋅⋅⋅π aromatic interactions, a through-space event. Modulating the π-ring (forming the aromatic interaction) with substituent groups resulted in a linear Hammett relationship, thus indicating that the CH⋅⋅⋅π interaction has electrostatic features. For instance, attaching a nitro group (an electron-withdrawing substituent) to the π-ring weakened the CH⋅⋅⋅π interaction and led to a gauche preference, whereas an anti conformer is preferred with amine as substituent. The experimental results performed by using proton NMR spectroscopy are corroborated by gas-phase DFT calculations and solid-state X-ray crystallography.
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Affiliation(s)
- Bright U Emenike
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Amiel Farshadmand
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Matthias Zeller
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
| | - Armando J Roman
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Arzu Sevimler
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - David W Shinn
- Department of Mathematics and Science, United States Merchant Marine Academy, 300 Steamboat Road, Kings Point, NY 11024, USA
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4
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Demkiw KM, Remmerswaal WA, Hansen T, van der Marel GA, Codée JDC, Woerpel KA. Halogen Atom Participation in Guiding the Stereochemical Outcomes of Acetal Substitution Reactions. Angew Chem Int Ed Engl 2022; 61:e202209401. [PMID: 35980341 PMCID: PMC9561118 DOI: 10.1002/anie.202209401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Indexed: 01/11/2023]
Abstract
Acetal substitution reactions of α-halogenated five- and six-membered rings can be highly stereoselective. Erosion of stereoselectivity occurs as nucleophilicity increases, which is consistent with additions to a halogen-stabilized oxocarbenium ion, not a three-membered-ring halonium ion. Computational investigations confirmed that the open-form oxocarbenium ions are the reactive intermediates involved. Kinetic studies suggest that hyperconjugative effects and through-space electrostatic interactions can both contribute to the stabilization of halogen-substituted oxocarbenium ions.
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Affiliation(s)
- Krystyna M. Demkiw
- Department of ChemistryNew York University100 Washington Square EastNew YorkNY 10003USA
| | - Wouter A. Remmerswaal
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 552300 RALeidenThe Netherlands
| | - Thomas Hansen
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 552300 RALeidenThe Netherlands
| | | | - Jeroen D. C. Codée
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 552300 RALeidenThe Netherlands
| | - K. A. Woerpel
- Department of ChemistryNew York University100 Washington Square EastNew YorkNY 10003USA
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5
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Demkiw KM, Remmerswaal WA, Hansen T, van der Marel GA, Codée JDC, Woerpel K. Halogen Atom Participation in Guiding the Stereochemical Outcomes of Acetal Substitution Reactions. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209401] [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)
- Krystyna M. Demkiw
- New York University Department of Chemistry Department of ChemistryNew York University100 Washington Square East 10003 New York UNITED STATES
| | - Wouter A. Remmerswaal
- Leiden University: Universiteit Leiden Leiden Institute of Chemistry Einsteinweg 552333 CC Leiden NETHERLANDS
| | - Thomas Hansen
- Leiden University: Universiteit Leiden Leiden Institute of Chemistry Einsteinweg 552333 CC Leiden NETHERLANDS
| | - Gijsbert A. van der Marel
- Leiden University: Universiteit Leiden Leiden Institute of Chemistry Einsteinweg 552333 CC Leiden NETHERLANDS
| | - Jeroen D. C. Codée
- Leiden University: Universiteit Leiden Leiden Institute of Chemistry Einsteinweg 552333 CC Leiden NETHERLANDS
| | - Keith Woerpel
- NYU: New York University Chemistry 100 Washington Square East 10003 New York UNITED STATES
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6
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Demkiw KM, Hu CT, Woerpel KA. Hyperconjugative Interactions of the Carbon-Halogen Bond that Influence the Geometry of Cyclic α-Haloacetals. J Org Chem 2022; 87:5315-5327. [PMID: 35363473 PMCID: PMC9036965 DOI: 10.1021/acs.joc.2c00148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The analysis of the structures of low-energy conformers of different α-haloacetals reveals changes in bond lengths and geometries that correspond to stabilizing orbital interactions that contribute to the ground-state structures of these systems. Several factors, including the electron-donating and electron-accepting abilities of the substituents on the ring, affect the degree of the electronic interactions in these carbohydrate-like systems. The presence of an α-halogen atom that can participate in hyperconjugation has been shown to contribute to the structural characteristics of the low-energy conformer. The experimental evidence is supported by natural bond order (NBO) analysis to identify the types of interactions and to assess their relative importance.
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Affiliation(s)
- Krystyna M Demkiw
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
| | - Chunhua T Hu
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
| | - K A Woerpel
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States
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7
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Port VC, Cormanich RA. There and back again: the role of hyperconjugation in the fluorine gauche effect. Phys Chem Chem Phys 2021; 23:17329-17337. [PMID: 34346435 DOI: 10.1039/d1cp02806e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The origin of the fluorine gauche effect has been debated for decades and recently different interpretations have been raised in the scientific community as new computational methods emerged and were applied to rationalize 1,2-difluoroethane (DFE) gauche preference. In this context, we revisited 1,2-difluoroethane (DFE) and its chlorine and bromine derivative conformational preferences through a comparative approach: the conformational behavior and hyperconjugative, steric and electrostatic contributions for the internal rotational barrier of DFE were compared with several analogue backbones, such as peroxides, disulfides and ammonia boranes. By using the Natural Bond Orbital (NBO) analysis it was found that hyperconjugation is the driving force of the conformational preference in DFE and its chlorine and bromine analogues. Electrostatics was found to be negligible and steric effects played a minor role in general, but are important in ClCH2CH2Cl and BrCH2CH2Br to counterbalance gauche stabilization by hyperconjugation and for the preference of the anti conformer.
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Affiliation(s)
- Vinicius C Port
- University of Campinas, Chemistry Institute, Monteiro Lobato Street, Campinas, Sao Paulo 13083-862, Brazil.
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8
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Datta S, Limpanuparb T. Steric effects vs. electron delocalization: a new look into the stability of diastereomers, conformers and constitutional isomers. RSC Adv 2021; 11:20691-20700. [PMID: 35479364 PMCID: PMC9033979 DOI: 10.1039/d1ra02877d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/24/2021] [Indexed: 01/22/2023] Open
Abstract
A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of compounds made of C, N, P, O and S atoms as core structures and halogens H, F, Cl, Br and I as substituents. All possible structures were generated and investigated by quantum mechanical methods. The prevalence of a formula in which its Z configuration, gauche conformation or meta isomer is the most stable form is calculated and discussed. Quantitative and qualitative models to explain the stability of the 23 classes of halogenated compounds were also proposed.
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Affiliation(s)
- Sopanant Datta
- Science Division, Mahidol University International College, Mahidol University Salaya Nakhon Pathom 73170 Thailand
| | - Taweetham Limpanuparb
- Science Division, Mahidol University International College, Mahidol University Salaya Nakhon Pathom 73170 Thailand
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9
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Rodrigues Silva D, de Azevedo Santos L, Hamlin TA, Fonseca Guerra C, Freitas MP, Bickelhaupt FM. The Gauche Effect in XCH 2 CH 2 X Revisited. Chemphyschem 2021; 22:641-648. [PMID: 33555663 PMCID: PMC8048458 DOI: 10.1002/cphc.202100090] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Indexed: 11/22/2022]
Abstract
We have quantum chemically investigated the rotational isomerism of 1,2-dihaloethanes XCH2 CH2 X (X = F, Cl, Br, I) at ZORA-BP86-D3(BJ)/QZ4P. Our Kohn-Sham molecular orbital (KS-MO) analyses reveal that hyperconjugative orbital interactions favor the gauche conformation in all cases (X = F-I), not only for X = F as in the current model of this so-called gauche effect. We show that, instead, it is the interplay of hyperconjugation with Pauli repulsion between lone-pair-type orbitals on the halogen substituents that constitutes the causal mechanism for the gauche effect. Thus, only in the case of the relatively small fluorine atoms, steric Pauli repulsion is too weak to overrule the gauche preference of the hyperconjugative orbital interactions. For the larger halogens, X⋅⋅⋅X steric Pauli repulsion becomes sufficiently destabilizing to shift the energetic preference from gauche to anti, despite the opposite preference of hyperconjugation.
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Affiliation(s)
- Daniela Rodrigues Silva
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - Lucas de Azevedo Santos
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - Trevor A. Hamlin
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
| | - Célia Fonseca Guerra
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Leiden Institute of ChemistryGorlaeus LaboratoriesLeiden UniversityEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Matheus P. Freitas
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - F. Matthias Bickelhaupt
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Institute for Molecules and Materials (IMM)Radboud UniversityHeyendaalseweg 1356525 AJNijmegen (TheNetherlands
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10
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Martins FA, Freitas MP. The FluorinegaucheEffect and a Comparison with Other Halogens in 2-Halofluoroethanes and 2-Haloethanols. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901234] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Francisco A. Martins
- Department of Chemistry; Federal University of Lavras; 37200-000 Lavras MG Brazil
| | - Matheus P. Freitas
- Department of Chemistry; Federal University of Lavras; 37200-000 Lavras MG Brazil
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11
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Wang B, Yu D, Zhao D, Rong C, Liu S. Nature and origin of γ-gauche effect in sulfoxides: A density functional theory and information-theoretic approach study. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.06.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Andrade LA, Silla JM, Freitas MP. An anomalous effect of fluorine on the conformational equilibrium of 2-fluorocyclohexane-1,3-dione. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2018.12.055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Tahchieva DN, Bakowies D, Ramakrishnan R, von Lilienfeld OA. Torsional Potentials of Glyoxal, Oxalyl Halides, and Their Thiocarbonyl Derivatives: Challenges for Popular Density Functional Approximations. J Chem Theory Comput 2018; 14:4806-4817. [PMID: 30011363 DOI: 10.1021/acs.jctc.8b00174] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reliability of popular density functionals was studied for the description of torsional profiles of 36 molecules: glyoxal, oxalyl halides, and their thiocarbonyl derivatives. HF and 18 functionals of varying complexity, from local density to range-separated hybrid approximations and double-hybrid, have been considered and benchmarked against CCSD(T)-level rotational profiles. For molecules containing heavy halogens, most functionals fail to reproduce barrier heights accurately and a number of functionals introduce spurious minima. Dispersion corrections show no improvement. Calibrated torsion-corrected atom-centered potentials rectify the shortcomings of PBE and also improve on σ-hole based intermolecular binding in dimers and crystals.
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Affiliation(s)
- Diana N Tahchieva
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - Dirk Bakowies
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - Raghunathan Ramakrishnan
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - O Anatole von Lilienfeld
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
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14
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Alabugin IV, dos Passos Gomes G, Abdo MA. Hyperconjugation. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1389] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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15
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Martins FA, Silla JM, Freitas MP. Conformational impact of structural modifications in 2-fluorocyclohexanone. Beilstein J Org Chem 2017; 13:1781-1787. [PMID: 28904621 PMCID: PMC5588668 DOI: 10.3762/bjoc.13.172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/10/2017] [Indexed: 11/23/2022] Open
Abstract
2-Haloketones are building blocks that combine physical, chemical and biological features of materials and bioactive compounds, while organic fluorine plays a fundamental role in the design of performance organic molecules. Since these features are dependent on the three-dimensional chemical structure of a molecule, simple structural modifications can affect its conformational stability and, consequently, the corresponding physicochemical/biological property of interest. In this work, structural changes in 2-fluorocyclohexanone were theoretically studied with the aim at finding intramolecular interactions that induce the conformational equilibrium towards the axial or equatorial conformer. The interactions evaluated were hydrogen bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classical effects indeed rule the conformational equilibrium of the compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants), which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.
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Affiliation(s)
- Francisco A Martins
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil
| | - Josué M Silla
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil
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16
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Planken S, Behenna DC, Nair SK, Johnson TO, Nagata A, Almaden C, Bailey S, Ballard TE, Bernier L, Cheng H, Cho-Schultz S, Dalvie D, Deal JG, Dinh DM, Edwards MP, Ferre RA, Gajiwala KS, Hemkens M, Kania RS, Kath JC, Matthews J, Murray BW, Niessen S, Orr STM, Pairish M, Sach NW, Shen H, Shi M, Solowiej J, Tran K, Tseng E, Vicini P, Wang Y, Weinrich SL, Zhou R, Zientek M, Liu L, Luo Y, Xin S, Zhang C, Lafontaine J. Discovery of N-((3R,4R)-4-Fluoro-1-(6-((3-methoxy-1-methyl-1H-pyrazol-4-yl)amino)-9-methyl-9H-purin-2-yl)pyrrolidine-3-yl)acrylamide (PF-06747775) through Structure-Based Drug Design: A High Affinity Irreversible Inhibitor Targeting Oncogenic EGFR Mutants with Selectivity over Wild-Type EGFR. J Med Chem 2017; 60:3002-3019. [PMID: 28287730 DOI: 10.1021/acs.jmedchem.6b01894] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mutant epidermal growth factor receptor (EGFR) is a major driver of non-small-cell lung cancer (NSCLC). Marketed first generation inhibitors, such as erlotinib, effect a transient beneficial response in EGFR mutant NSCLC patients before resistance mechanisms render these inhibitors ineffective. Secondary oncogenic EGFR mutations account for approximately 50% of relapses, the most common being the gatekeeper T790M substitution that renders existing therapies ineffective. The discovery of PF-06459988 (1), an irreversible pyrrolopyrimidine inhibitor of EGFR T790M mutants, was recently disclosed.1 Herein, we describe our continued efforts to achieve potency across EGFR oncogenic mutations and improved kinome selectivity, resulting in the discovery of clinical candidate PF-06747775 (21), which provides potent EGFR activity against the four common mutants (exon 19 deletion (Del), L858R, and double mutants T790M/L858R and T790M/Del), selectivity over wild-type EGFR, and desirable ADME properties. Compound 21 is currently being evaluated in phase-I clinical trials of mutant EGFR driven NSCLC.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Longqing Liu
- Wuxi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Yiqin Luo
- Wuxi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Shuibo Xin
- Wuxi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
| | - Chengyi Zhang
- Wuxi AppTec, 288 Fute Zhong Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China
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17
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Baranac-Stojanović M, Stojanović M, Aleksić J. Theoretical study of azido gauche effect and its origin. NEW J CHEM 2017. [DOI: 10.1039/c7nj00369b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The strength and origin of the azido gauche effect were studied by ab initio calculations and compared with the well-known fluorine gauche effect.
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Affiliation(s)
| | | | - Jovana Aleksić
- Center for Chemistry ICTM
- University of Belgrade
- 11000 Belgrade
- Serbia
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18
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Huchet QA, Schweizer WB, Kuhn B, Carreira EM, Müller K. Structural and Conformational Aspects of Equatorial and Axial Trifluoromethyl, Difluoromethyl, and Monofluoromethyl Groups. Chemistry 2016; 22:16920-16928. [DOI: 10.1002/chem.201602643] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Quentin A. Huchet
- ETH Zürich; Laboratorium für Organische Chemie; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - W. Bernd Schweizer
- ETH Zürich; Laboratorium für Organische Chemie; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Bernd Kuhn
- F. Hoffmann-La Roche AG; Pharmaceutical Research & Early Development; Roche Innovation Center Basel; Grenzacherstrasse 124 4070 Basel Switzerland
| | - Erick M. Carreira
- ETH Zürich; Laboratorium für Organische Chemie; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
| | - Klaus Müller
- ETH Zürich; Laboratorium für Organische Chemie; Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
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19
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Affiliation(s)
- Christian Thiehoff
- Institute for Organic Chemistry; Westfälische Wilhelms-Universität Münster; Corrensstr. 40 48149 Münster Germany
| | - Yannick P. Rey
- Institute for Organic Chemistry; Westfälische Wilhelms-Universität Münster; Corrensstr. 40 48149 Münster Germany
| | - Ryan Gilmour
- Institute for Organic Chemistry; Westfälische Wilhelms-Universität Münster; Corrensstr. 40 48149 Münster Germany
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20
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Vidhani DV, Krafft ME, Alabugin IV. Gold(I)-Catalyzed Allenyl Cope Rearrangement: Evolution from Asynchronicity to Trappable Intermediates Assisted by Stereoelectronic Switching. J Am Chem Soc 2016; 138:2769-79. [DOI: 10.1021/jacs.5b12920] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dinesh V. Vidhani
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Marie E. Krafft
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Igor V. Alabugin
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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21
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Measurement, Interpretation and Use of Free Ligand Solution Conformations in Drug Discovery. PROGRESS IN MEDICINAL CHEMISTRY 2016; 55:45-147. [DOI: 10.1016/bs.pmch.2015.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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22
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O'Connor MJ, Liu H, Lee D, Zhou T, Xia Y. DFT Studies on the Stereoselectivity of α-Silyloxy Diazoalkane Cycloadditions. Molecules 2015; 20:21433-41. [PMID: 26633338 PMCID: PMC6331888 DOI: 10.3390/molecules201219783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 11/18/2015] [Accepted: 11/26/2015] [Indexed: 11/16/2022] Open
Abstract
The intramolecular [3+2] cycloaddition (32CA) of alkene-tethered α-silyloxydiazoalkanes provides variable stereoselectivity in generating bicyclic pyrazolines where the silyloxy group is either syn or anti to the newly formed pyrazoline ring. To elucidate the origin of the stereoselectivity, density functional theory (DFT) calculations were carried out for the energy of each transition state structure (TSs) and product. Steric effects were identified as the major determining factors in the diastereoselectivity of the 32CA reaction with regards to substrate structure (cyclic or acyclic α-silyloxydiazoalkanes).
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Affiliation(s)
- Matthew J O'Connor
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago 60607, IL, USA.
| | - Huaqing Liu
- Abbvie Inc., 1 North Waukegan Road, North Chicago 60064, IL, USA.
| | - Daesung Lee
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago 60607, IL, USA.
| | - Tao Zhou
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, China.
| | - Yuanzhi Xia
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, China.
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23
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Lin HS, Lu SY, Huang FY, Wu Y, Su WL, Wang SP. An Insight of the Results Provided by Color-Tuning Studies Made on Ir(III) Complexes: A pi-Neutral CF3Group Viewed by Adjusting Energies of pi-type Molecular Orbitals. J CHIN CHEM SOC-TAIP 2015. [DOI: 10.1002/jccs.201400271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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24
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Santschi N, Aiguabella N, Lewe V, Gilmour R. Delineating the physical organic profile of the 6-fluoro glycosyl donor. J Fluor Chem 2015. [DOI: 10.1016/j.jfluchem.2015.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Aleksić J, Stojanović M, Baranac-Stojanović M. Origin of Fluorine/Sulfur Gauche Effect of β-Fluorinated Thiol, Sulfoxide, Sulfone, and Thionium Ion. J Org Chem 2015; 80:10197-207. [DOI: 10.1021/acs.joc.5b01779] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jovana Aleksić
- Center
for Chemistry ICTM, University of Belgrade, P.O. Box 473, 11000 Belgrade, Serbia
| | - Milovan Stojanović
- Center
for Chemistry ICTM, University of Belgrade, P.O. Box 473, 11000 Belgrade, Serbia
| | - Marija Baranac-Stojanović
- Faculty
of Chemistry, University of Belgrade, Studentski trg 12-16, P.O. Box 158, 11000 Belgrade, Serbia
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26
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Thiehoff C, Holland MC, Daniliuc C, Houk KN, Gilmour R. Can acyclic conformational control be achieved via a sulfur-fluorine gauche effect? Chem Sci 2015; 6:3565-3571. [PMID: 29511517 PMCID: PMC5659174 DOI: 10.1039/c5sc00871a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/16/2015] [Indexed: 01/04/2023] Open
Abstract
The gauche conformation of the 1,2-difluoroethane motif is known to involve stabilising hyperconjugative interactions between donor (bonding, σC-H) and acceptor (antibonding, σ*C-F) orbitals. This model rationalises the generic conformational preference of F-Cβ-Cα-X systems (φFCCX ≈ 60°), where X is an electron deficient substituent containing a Period 2 atom. Little is known about the corresponding Period 3 systems, such as sulfur and phosphorus, where multiple oxidation states are possible. Conformational analyses of β-fluorosulfides, -sulfoxides and -sulfones are disclosed here, thus extending the scope of the fluorine gauche effect to the 3rd Period (F-C-C-S(O) n ; φFCCS ≈ 60°). Synergy between experiment and computation has revealed that the gauche effect is only pronounced in structures bearing an electropositive vicinal sulfur atom (S+-O-, SO2).
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Affiliation(s)
- C Thiehoff
- Organisch Chemisches Institut, and Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Corrensstrasse 40 , Münster , Germany .
| | - M C Holland
- Organisch Chemisches Institut, and Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Corrensstrasse 40 , Münster , Germany .
- Department of Chemistry and Biochemistry , University of California Los Angeles , 607 Charles E. Young Drive East , Los Angeles 90095-1569 , USA .
| | - C Daniliuc
- Organisch Chemisches Institut, and Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Corrensstrasse 40 , Münster , Germany .
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California Los Angeles , 607 Charles E. Young Drive East , Los Angeles 90095-1569 , USA .
| | - R Gilmour
- Organisch Chemisches Institut, and Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Corrensstrasse 40 , Münster , Germany .
- Excellence Cluster EXC 1003 , Cells in Motion , Westfälische Wilhelms-Universität Münster , Münster , Germany
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27
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Alapour S, Ramjugernath D, Koorbanally NA. Copper-catalysed cross-coupling affected by the Smiles rearrangement: a new chapter on diversifying the synthesis of chiral fluorinated 1,4-benzoxazine derivatives. RSC Adv 2015. [DOI: 10.1039/c5ra18897k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Synthesis of novel derivatives of fluorinated benzoxazines was achieved through the Smiles rearrangement. The gauche conformation of selected precursors enabled the reaction to occur at room temperature at yields of 90%.
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Affiliation(s)
- Saba Alapour
- School of Chemistry
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Deresh Ramjugernath
- School of Chemical Engineering
- University of KwaZulu-Natal
- Durban 4000
- South Africa
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28
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Abstract
The conformational behaviour of Ac-Gly-NHMe and its fluorinated [CF3-C(O)-Gly-NHMe] and N-methyl[Ac-Gly-N(Me)2] derivatives is investigated in nonpolar, polar and polar protic solutions by NMR and IR spectroscopies and theoretical calculations.
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Affiliation(s)
- R. A. Cormanich
- EastChem School of Chemistry
- University of St Andrews
- St Andrews
- UK
- Chemistry Institute
| | - R. Rittner
- Chemistry Institute
- State University of Campinas
- Campinas
- Brazil
| | - M. Bühl
- EastChem School of Chemistry
- University of St Andrews
- St Andrews
- UK
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29
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Baranac-Stojanović M, Aleksić J, Stojanović M. Energy decomposition analysis of gauche preference in 2-haloethanol, 2-haloethylamine (halogen = F, Cl), their protonated forms and anti preference in 1-chloro-2-fluoroethane. RSC Adv 2015. [DOI: 10.1039/c5ra01164g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Small, electronegative elements contribute more electrostatic and orbital stabilization to the anti → gauche isomerization, and greater steric repulsion. The first and the latter actually oppose our traditional view of conformational equilibria.
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Affiliation(s)
| | - Jovana Aleksić
- Center for Chemistry ICTM
- University of Belgrade
- 11000 Belgrade
- Serbia
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30
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Baranac-Stojanović M. Gauche preference in 1,2-difluoroethane originates from both orbital and electrostatic stabilization interactions. RSC Adv 2014. [DOI: 10.1039/c4ra07909d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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31
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Rey YP, Zimmer LE, Sparr C, Tanzer EM, Schweizer WB, Senn HM, Lakhdar S, Gilmour R. Molecular Design Exploiting a FluorinegaucheEffect as a Stereoelectronic Trigger. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301730] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Bent bonds and the antiperiplanar hypothesis as a simple model to predict Diels–Alder reactivity: retrospective or perspective? Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.05.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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33
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Luo Q, Randall KR, Schaefer HF. Easy chairs: the conformational preferences of polyfluorocyclohexanes. RSC Adv 2013. [DOI: 10.1039/c3ra40538a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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34
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Urbina-Blanco CA, Skibiński M, O'Hagan D, Nolan SP. Accelerating influence of the gem-difluoromethylene group in a ring-closing olefin metathesis reaction. A Thorpe–Ingold effect? Chem Commun (Camb) 2013; 49:7201-3. [DOI: 10.1039/c3cc44312d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Combettes LE, Clausen-Thue P, King MA, Odell B, Thompson AL, Gouverneur V, Claridge TDW. Conformational analysis of fluorinated pyrrolidines using 19F-1H scalar couplings and heteronuclear NOEs. Chemistry 2012; 18:13133-41. [PMID: 22991298 DOI: 10.1002/chem.201201577] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Indexed: 11/07/2022]
Abstract
A series of 3-fluoropyrrolidines have been studied to investigate the influence of the stereoelectronic fluorine gauche effect on ring conformations in the solid state by single-crystal X-ray analysis and in solution phase by NMR spectroscopy. As part of these studies 1D (19)F-(1)H heteronuclear NOE (HOESY) experiments have been optimised for applications to small molecules and are described in detail. These have been employed to estimate (19)F-(1)H internuclear distances and were combined with vicinal (3)J(F,H) and (3)J(H,H) scalar coupling constants to analyse the ring conformations. Where possible the derived solution-phase structural data have been compared with those of the crystalline state. The results demonstrate the influence of the gauche effect in stabilising C(γ)-exo conformations of the fluorinated pyrrolidines. It was further shown that when steric interactions were also present, this conformational bias was diminished and the contribution of the alternative C(γ)-endo conformation was seen to increase in solution at lower sample temperatures.
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Affiliation(s)
- Lorraine E Combettes
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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36
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Yamada Y, Noboru Y, Sakaguchi T, Nibu Y. Conformation of 2,2,2-Trifluoroethanol and the Solvation Structure of Its 2-Fluoropyridine Clusters. J Phys Chem A 2012; 116:2845-54. [DOI: 10.1021/jp300721r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yuji Yamada
- Department
of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan
| | - Yusuke Noboru
- Department
of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan
| | - Takuma Sakaguchi
- Department
of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan
| | - Yoshinori Nibu
- Department
of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan
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37
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Borden WT. With a Little Help from My Friends: Forty Years of Fruitful Chemical Collaborations. J Org Chem 2011; 76:2943-64. [PMID: 21452841 DOI: 10.1021/jo200213x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Weston Thatcher Borden
- Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle #305070, Denton, Texas 76203-5017, United States
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38
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Alabugin IV, Gilmore KM, Peterson PW. Hyperconjugation. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.6] [Citation(s) in RCA: 214] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Igor V. Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
| | - Kerry M. Gilmore
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
| | - Paul W. Peterson
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
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39
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Takahashi O, Kohno Y, Nishio M. Relevance of weak hydrogen bonds in the conformation of organic compounds and bioconjugates: evidence from recent experimental data and high-level ab initio MO calculations. Chem Rev 2011; 110:6049-76. [PMID: 20550180 DOI: 10.1021/cr100072x] [Citation(s) in RCA: 447] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Osamu Takahashi
- Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8526, Japan.
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40
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Deslongchamps G, Deslongchamps P. Bent bonds, the antiperiplanar hypothesis and the theory of resonance. A simple model to understand reactivity in organic chemistry. Org Biomol Chem 2011; 9:5321-33. [DOI: 10.1039/c1ob05393k] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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42
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Martins LE, Freitas MP. Anomeric effect plays a major role in the conformational isomerism of fluorinated pnictogen compounds. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1397] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Souza FR, Freitas MP, Rittner R. On the stereoelectronic effects governing the rotational isomerism of 1,2-di-haloethanes. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2008.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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44
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Exner O, Böhm S. Regularities of the conformations on a single bond; sulfonic esters and sulfonyl derivatives. NEW J CHEM 2008. [DOI: 10.1039/b709410h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Hyla-Kryspin I, Grimme S, Hruschka S, Haufe G. Conformational preferences and basicities of monofluorinated cyclopropyl amines in comparison to cyclopropylamine and 2-fluoroethylamine. Org Biomol Chem 2008; 6:4167-75. [DOI: 10.1039/b810108f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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47
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Mayato C, Dorta RL, Vázquez JT. New insights into the conformational properties of α-C-glucosides. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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49
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Freitas MP, Rittner R. Is There a General Rule for the Gauche Effect in the Conformational Isomerism of 1,2-Disubstituted Ethanes? J Phys Chem A 2007; 111:7233-6. [PMID: 17616112 DOI: 10.1021/jp0728196] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The stabilities of the gauche and anti conformations of butane, 1,2-dicyanoethane (DCE), and 1,2-dinitroethane (DNE) have been investigated through theoretical calculations. The gauche effect-the tendency of keeping close vicinal electronegative substituents (thetaX-C-C-X approximately 60 degrees ) in an ethane fragment-is expected to drive the conformational equilibrium of DCE and DNE toward the gauche conformation. It was found that, for butane, where the gauche effect is supposed to be poor/null, the hyperconjugation effect contributes mostly to the anti stabilization in opposition to the traditional sense that the methyl groups repel each other, and this should govern its conformational equilibrium. For DCE the equilibrium was shifted to the anti conformer, essentially due to a gauche repulsion, while for DNE, despite the higher electronic delocalization energies, a predominance of the gauche conformer was obtained, and this was attributed mainly to the attractive dipolar interaction between the two nitro groups. A full orbital energy analysis was performed using the natural bond orbital approach, which showed that bond bending and anti-C-H/C-X* hyperconjugation models, usually applied to explain the origin of the gauche effect in fluorinated derivatives, are not adequate to completely explain the conformational behavior of the titled compounds.
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Affiliation(s)
- Matheus P Freitas
- Departamento de Química, Universidade Federal de Lavras, C.P. 3037, 37200-000 Lavras, MG, Brazil.
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50
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Charafeddine A, Dayoub W, Chapuis H, Strazewski P. First Synthesis of 2′-Deoxyfluoropuromycin Analogues: Experimental Insight into the Mechanism of the Staudinger Reaction. Chemistry 2007; 13:5566-84. [PMID: 17455187 DOI: 10.1002/chem.200700058] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The N(6),N(6)-dedimethyl-2'-deoxyfluoro analogue of puromycin (= 3'-deoxy-N(6),N(6)-dimethyl-3'-[O-methyltyrosylamido]adenosine), its 2',3'-regioisomer and a 3'-cytidyl-5'-(2'-deoxyfluoro)puromycyl dinucleotide analogue were synthesized following an approach involving i) the diastereospecific nitrite-assisted formation of a lyxo nucleosidic 2',3'-epoxide from an adenosine-2',3'-ditriflate derivative in a biphasic solvent mixture; ii) the regio- and stereoselective epoxide ring opening with sodium azide under mildly acidic aqueous conditions, iii) the stereospecific introduction of the fluor atom using DAST and iv) the reaction between the nucleosidyl or dinucleotidyl azide and an active ester of the N-protected amino acid using highly efficient solution conditions for the Staudinger-Vilarrasa coupling, to obtain the corresponding carboxamide directly from the in situ formed iminophosphorane. This coupling reaction furnished sterically quite demanding amides in 94 % isolated yields under very mild conditions and should therefore be of a more general value. Under certain reaction conditions we isolated (amino)acyltriazene derivatives from which dinitrogen was not eliminated. These secondary products are trapped and stabilized witnesses of the first intermediate of the Staudinger reaction, the phosphatriazenes (phosphazides, triazaphosphadienes) which usually eliminate dinitrogen in situ and rapidly rearrange into iminophosphoranes, unless they are derived from conjugated or sterically bulky azides and phosphines. The acyltriazenes could either be thermally decomposed or converted to the corresponding N-alkyl carboxamides through proton-assisted elimination of dinitrogen. All compounds were carefully characterized through MS spectrometry, (1)H, (19)F, (31)P and (13)C NMR spectroscopy.
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Affiliation(s)
- Adib Charafeddine
- Laboratoire de Synthèse des Biomolécules, Bâtiment Eugène Chevreul, UMR UCBL-CNRS 5246, ICBMS, Université Claude Bernard Lyon 1, Domaine Scientifique de la Doua, 43 bvd du 11 novembre 1918, 69622 Villeurbanne Cedex, France
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