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Anjalikrishna PK, Suresh CH. Utilization of the through-space effect to design donor-acceptor systems of pyrrole, indole, isoindole, azulene and aniline. Phys Chem Chem Phys 2024; 26:1340-1351. [PMID: 38108385 DOI: 10.1039/d3cp03393g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Molecular electrostatic potential (MESP) topology analysis reveals the underlying phenomenon of the through-space effect (TSE), which imparts electron donor-acceptor properties to a wide range of chemical systems, including derivatives of pyrrole, indole, isoindole, azulene, and aniline. The TSE is inherent in pyrrole owing to the strong polarization of electron density (PoED) from the formally positively charged N-center to the C3C4 bonding region. The N → C3C4 directional nature of the TSE has been effectively employed to design molecules with high electronic polarization, such as bipyrroles, polypyrroles, phenyl pyrroles, multi-pyrrolyl systems and N-doped nanographenes. In core-expanded structures, the direction of electron flow from pyrrole units towards the core leads to highly electron-rich systems, while the opposite arrangement results in highly electron-deficient systems. Similarly, the MESP analysis reveals the presence of the TSE in azulene, indole, isoindole, and aniline. Oligomeric chains of these systems are designed in such a way that the direction of electron flow is consistent across each monomer, leading to substantial electronic polarization between the first and last monomer units. Notably, these designed systems exhibit strong donor-acceptor characteristics despite the absence of explicit donor and acceptor moieties, which is supported by FMO analysis, APT charge analysis, NMR data and λmax data. Among the systems studied, the TSEs of many experimentally known systems (bipyrroles, phenyl pyrroles, hexapyrrolylbenzene, octapyrrolylnaphthalene, decapyrrolylcorannulene, polyindoles, polyazulenes, etc.) are unraveled for the first time, while numerous new systems (polypyrroles, polyisoindoles, and amino-substituted benzene polymers) are predicted to be promising materials for the creation of donor-acceptor systems. These findings demonstrate the potential of the TSE in molecular design and provide new avenues for creating functional materials.
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Affiliation(s)
- Puthannur K Anjalikrishna
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala, 695019, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala, 695019, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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2
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Laconsay CJ, Rho TC, Tantillo DJ. The Role of Through-Bond Stereoelectronic Effects in the Reactivity of 3-Azabicyclo[3.3.1]nonanes. J Org Chem 2022; 87:3378-3388. [PMID: 35191711 DOI: 10.1021/acs.joc.1c02992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperconjugation/conjugation through-bond stereoelectronic effects were studied with density functional theory in the context of 3-azabicyclo[3.3.1]nonanes to unravel puzzling differences in reactivity between a vinylogous chloride (4) and a vinylogous ester (5). These compounds─whose structures differ only by one substituent─were found to display strikingly different reactivities in hydrochloric acid by Risch and co-workers ( J. Am. Chem. Soc., 1991, 113, 9411-9412). Computational analyses of substituent effects, noncovalent interactions, natural bond orbitals, isodesmic reactions, and hydration propensities lead to a model for which the role of remote, through-bond stereoelectronic effects is the key to explaining 4 and 5's diverging reactivity.
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Affiliation(s)
- Croix J Laconsay
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Tyler C Rho
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, California 95616, United States
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3
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Divya VV, Sayyed FB, Suresh CH. Substituent Effect Transmission Power of Alkyl, Alkenyl, Alkynyl, Phenyl, Thiophenyl, and Polyacene Spacers. Chemphyschem 2019; 20:1752-1758. [PMID: 30973660 DOI: 10.1002/cphc.201900206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Indexed: 11/08/2022]
Abstract
The transmission of substituent effect through a variety of spacers, that is to say, alkyl, alkenyl, alkynyl, phenyl, thiophenyl, and polyacene has been studied by modeling Y-G-X type molecular systems (Y: reaction center; G: spacer moiety; X: substituent) using B3LYP/6-31G(d,p) density functional theory calculations. The reaction center is always kept as a C=C double bond and the molecular electrostatic potential (MESP) minimum (Vmin ) observed for this bond showed subtle variation with respect to the changes in the spacer unit and the nature of substituent. Strong linear correlations are observed between Hammett substituent constants (σI and σp ) and Vmin , which recommend the aptness of Vmin as an electronic descriptor to quantify the substituent effect. Since Vmin offers an alternative measure of substituent effect, the correlation between Vmin and σp has been used for assessing the transmission of substituent effect through a variety of spacer moieties. The highest transmission coefficient (γ) is always observed for smaller spacer length. Among all the spacers, alkenyl showed the highest and alkyl showed the lowest transmission power. The study recommends the use of short chains of C=C double, C≡C triple or a combination of both as spacers for the effective transmission of substituent effect to the reaction center.
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Affiliation(s)
- Velayudhan V Divya
- Chemical Sciences and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology Thiruvananthapuram, Kerala, 695 019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-, 201002, India
| | - Fareed Bhasha Sayyed
- Chemical Sciences and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology Thiruvananthapuram, Kerala, 695 019, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology Thiruvananthapuram, Kerala, 695 019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-, 201002, India
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Wu J, Leas DA, Dong Y, Wang X, Ezell EL, Stack DE, Vennerstrom JL. Synthesis of 2-Azaadamantan-6-one: A Missing Isomer. ACS OMEGA 2018; 3:11362-11367. [PMID: 30288462 PMCID: PMC6166225 DOI: 10.1021/acsomega.8b01819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/10/2018] [Indexed: 05/04/2023]
Abstract
2-Azaadamantan-6-one and its Boc and ethylene ketal derivatives were synthesized from 9-oxo endo-bicyclo[3.3.1]non-6-ene-3-carboxylic acid. Similarly, the Cbz, Boc, and ethylene ketal derivatives of 2-azaadamantan-4-one were synthesized from endo-bicyclo[3.3.1]non-6-ene-3-carboxylic acid. Key steps were Curtius rearrangements to form benzyl carbamates, followed by spontaneous intramolecular attack of the carbamate nitrogen on transient bromonium ion or epoxide intermediates to effect ring closure to azaadamantane intermediates. The reaction sequence leading to 2-azaadamantan-6-one is consistent with the formation of a transient tetracyclic keto aziridine intermediate.
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Affiliation(s)
- Jianbo Wu
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Derek A. Leas
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Yuxiang Dong
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Xiaofang Wang
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Edward L. Ezell
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Douglas E. Stack
- Department
of Chemistry, University of Nebraska at
Omaha, Omaha, Nebraska 68182, United States
| | - Jonathan L. Vennerstrom
- College
of Pharmacy and Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
- E-mail: (J.L.V.)
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5
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Semipinacol and protoadamantane-adamantane rearrangements of 5,6-dibromoadamantan-2-one and -2-ol. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Tsuji M. Geometrical Dependence of the Highest Occupied Molecular Orbital in Bicyclic Systems: π-Facial Stereoselectivity of Bicyclic and Tricyclic Olefins. ASIAN J ORG CHEM 2015. [DOI: 10.1002/ajoc.201500054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Motonori Tsuji
- Graduate School of Pharmaceutical Sciences; University of Tokyo; 7-3-1 Hongo, Bunkyo-ku Tokyo 113-0033 Japan
- Institute of Molecular Function; 2-105-14 Takasu, Misato-shi Saitama 341-0037 Japan
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7
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Castro B, Chaudret R, Ricci G, Kurz M, Ochsenbein P, Kretzschmar G, Kraft V, Rossen K, Eisenstein O. Nonclassical CH−π Supramolecular Interactions in Artemisinic Acid Favor a Single Conformation, Yielding High Diastereoselectivity in the Reduction with Diazene. J Org Chem 2014; 79:5939-47. [DOI: 10.1021/jo500233z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Bertrand Castro
- Institut Charles
Gerhardt, CNRS 5253, Université Montpellier 2, cc 1501,
place E. Bataillon, F-34095 Montpellier, France
| | - Robin Chaudret
- IFP Energies Nouvelles, 1 et 4 avenue de Bois-Préau, 92852 Rueil-Malmaison Cedex, France
| | - Gino Ricci
- Sanofi Chimie, 45 chemin
de Meteline 04200 Sisteron, France
| | - Michael Kurz
- Sanofi-Aventis Deutschland GmbH, Chemistry & Biotechnology Department, Industriepark Höchst, D-65926 Frankfurt am Main, Germany
| | - Philippe Ochsenbein
- Sanofi-Aventis R & D, 371 rue du Professeur Joseph Blayac, 34184 Montpellier Cedex 04, France
| | - Gerhard Kretzschmar
- Sanofi-Aventis Deutschland GmbH, Chemistry & Biotechnology Department, Industriepark Höchst, D-65926 Frankfurt am Main, Germany
| | - Volker Kraft
- Sanofi-Aventis Deutschland GmbH, Chemistry & Biotechnology Department, Industriepark Höchst, D-65926 Frankfurt am Main, Germany
| | - Kai Rossen
- Sanofi-Aventis Deutschland GmbH, Chemistry & Biotechnology Department, Industriepark Höchst, D-65926 Frankfurt am Main, Germany
| | - Odile Eisenstein
- Institut Charles
Gerhardt, CNRS 5253, Université Montpellier 2, cc 1501,
place E. Bataillon, F-34095 Montpellier, France
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8
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Transmission of electronic substituent effects through cage polycyclic alkanes: a computational study of diamantane derivatives based on structural variation. Struct Chem 2014. [DOI: 10.1007/s11224-014-0400-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Campanelli AR, Domenicano A. A computational study of 4-substituted biphenyls in their minimum energy conformation: twist angles, structural variation, and substituent effects. Struct Chem 2013. [DOI: 10.1007/s11224-013-0242-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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11
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Adcock W. Calculated polar substituent effects on the stability of 3-substituted(X) bicyclo[1.1.1]pent-1-yl cations and 4-substituted(X) bicyclo[2.2.1]hept-1-yl cations: a DFT study. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- William Adcock
- School of Chemical and Physical Sciences; Flinders University; Adelaide SA 5001 Australia
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12
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Campanelli AR, Domenicano A, Ramondo F. Transmission of electronic substituent effects through a benzene framework: a computational study of 4-substituted biphenyls based on structural variation. J Phys Chem A 2012; 116:8209-17. [PMID: 22784397 DOI: 10.1021/jp303722w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The transmission of substituent effects through a benzene framework has been studied by a novel approach, based on the structural variation of the Ph group in p-Ph-C(6)H(4)-X molecules. The molecular structures of many 4-substituted biphenyls were determined from MO calculations at the HF/6-31G* and B3LYP/6-311++G** levels of theory. The twist angle between the phenyl probe (ring B) and the benzene framework carrying the substituent (ring A) was set at 90° to prevent π-electron transfer from one ring to the other and at 0° to maximize it. The structural variation of the probe is best represented by a linear combination of the internal ring angles, termed S(F)(BIPH(o)) and S(F)(BIPH(c)) for the orthogonal and coplanar conformations of the molecules, respectively. Regression analysis of these parameters using appropriate explanatory variables reveals a composite field effect, a substantial proportion of which is originated by resonance-induced π-charges on the carbon atoms of ring A. Field-induced polarization of the π-system of ring A also contributes to the structural variation of the probe. Thus, the S(F)(BIPH(o)) parameter is very well reproduced by a linear combination of the π-charges on the ortho, meta, and para carbons of ring A, an uncommon example of a quantitative relationship between molecular geometry and electron density distribution. Comparison of S(F)(BIPH(o)) with the gas-phase acidities of para-substituted benzoic acids shows that, while the deprotonating carboxylic probe is more sensitive to π-electron withdrawal than donation, the phenyl probe is equally sensitive to both. While the ability of the orthogonal biphenyl system to exchange π-electrons with the para substituent is the same as that of the benzene ring in Ph-X molecules, an increase by about 18% occurs when the conformation is changed from orthogonal to coplanar. The structural variation of the probe becomes more complicated, however. This is due to π-electron transfer from one ring to the other, which is shown to introduce quadratic terms in the regressions.
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13
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Zarycz N, Aucar GA. Analysis of Electron Correlation Effects and Contributions of NMR J-Couplings from Occupied Localized Molecular Orbitals. J Phys Chem A 2012; 116:1272-82. [DOI: 10.1021/jp209850z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Natalia Zarycz
- Department of Physics, Natural and Exact Science Faculty,
Northeastern University of Argentina, Corrientes, Argentina
| | - Gustavo A. Aucar
- Department of Physics, Natural and Exact Science Faculty,
Northeastern University of Argentina, Corrientes, Argentina
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14
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Knoll W, Kaneno D, Bobek MM, Brecker L, Rosenberg MG, Tomoda S, Brinker UH. Intra- and Intermolecular Reaction Selectivities of γ-Substituted Adamantanylidenes. J Org Chem 2012; 77:1340-60. [DOI: 10.1021/jo202132c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wolfgang Knoll
- Chair of Physical Organic and
Structural Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38,
A-1090 Vienna, Austria
| | - Daisuke Kaneno
- Department
of Life Sciences, Graduate
School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-Ku, Tokyo 153-8902, Japan
| | - Michael M. Bobek
- Chair of Physical Organic and
Structural Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38,
A-1090 Vienna, Austria
| | - Lothar Brecker
- Chair of Physical Organic and
Structural Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38,
A-1090 Vienna, Austria
| | - Murray G. Rosenberg
- Chair of Physical Organic and
Structural Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38,
A-1090 Vienna, Austria
| | - Shuji Tomoda
- Department
of Life Sciences, Graduate
School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-Ku, Tokyo 153-8902, Japan
| | - Udo H. Brinker
- Chair of Physical Organic and
Structural Chemistry, Institute of Organic Chemistry, University of Vienna, Währinger Strasse 38,
A-1090 Vienna, Austria
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15
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Sayyed FB, Suresh CH. Quantitative assessment of substituent effects on cation-π interactions using molecular electrostatic potential topography. J Phys Chem A 2011; 115:9300-7. [PMID: 21774520 DOI: 10.1021/jp205064y] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A molecular electrostatic potential (MESP) topography based approach has been proposed to quantify the substituent effects on cation-π interactions in complexes of mono-, di-, tri-, and hexasubstituted benzenes with Li(+), Na(+), K(+), and NH(4)(+). The MESP minimum (V(min)) on the π-region of C(6)H(5)X showed strong linear dependency to the cation-π interaction energy, E(M(+)). Further, cation-π distance correlated well with V(min)-π distance. The difference between V(min) of C(6)H(5)X and C(6)H(6) (ΔV(min)) is proposed as a good parameter to quantify the substituent effect on cation-π interaction. Compared to benzene, electron-donating groups stabilize the di-, tri-, and hexasubstituted cation-π complexes while electron-withdrawing groups destabilize them. In multiple substituted complexes, E(M(+)) is almost equal (∼95%) to the sum of the individual substituent contributions (E(M(+)) ≈ Σ(ΔE(M(+)))), suggesting that substituent effect on cation-π interactions is largely additive. The ΔV(min) of C(6)H(5)X systems and additivity feature have been used to make predictions on the interaction energies of 80 multiple substituted cation-π complexes with above 97% accuracy. The average mean absolute deviation of the V(min)-predicted interaction energy, E(M(+))(V) from the calculated E(M(+)) is -0.18 kcal/mol for Li(+), -0.09 kcal/mol for Na(+), -0.43 kcal/mol for K(+), and -0.67 kcal/mol for NH(4)(+), which emphasize the predictive power of V(min) as well as the additive feature of the substituent effect.
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Affiliation(s)
- Fareed Bhasha Sayyed
- Computational Modeling and Simulation Section, National Institute for Interdisciplinary Science and Technology (CSIR), Trivandrum, India 695019
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16
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Structural variations and electronic substituent effects in phenylcubane derivatives: a quantum chemical study. Struct Chem 2011. [DOI: 10.1007/s11224-011-9750-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Ohwada T. Orbital phase environments and stereoselectivities. Top Curr Chem (Cham) 2011; 289:129-81. [PMID: 21279574 DOI: 10.1007/128_2008_38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Facial selections are reviewed to propose a new theory, orbital phase environment, for stereoselectivities of organic reactions. The orbital phase environment is a generalized idea of the secondary orbital interaction between the non-reacting centers and the unsymmetrization of the orbitals at the reacting centers arising from in-phase and out-of-phase overlapping with those at the neighboring non-reacting sites. In this context, the nucleophilic addition preferentially occurs on the face of the carbonyl functionality opposite to the better electron-donating orbital at the β position. In a similar manner to the carbonyl cases, the preferred reaction faces of olefins in electrophilic addition reactions are opposite to the better electron-donating orbitals at the β positions. The orbital phase environments in Diels-Alder reactions are also reviewed.
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Affiliation(s)
- Tomohiko Ohwada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113, Japan,
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18
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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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Bartoli G, Marcantoni E, Marcolini M, Sambri L. Applications of CeCl(3) as an environmental friendly promoter in organic chemistry. Chem Rev 2011; 110:6104-43. [PMID: 20731375 DOI: 10.1021/cr100084g] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Giuseppe Bartoli
- Department of Organic Chemistry A. Mangini, University of Bologna, viale Risorgimento 4, I-40156 Bologna, Italy
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20
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Adcock W. A DFT-GIAO and DFT-NBO study of polar substituent effects on NMR 17
O chemical shifts in some rigid polycyclic alkanes. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Adcock W. Calculated polar substituent effects on the stability of 4-substituted(X) - cub-1-yl and -bicyclo[2.2.2]oct-1-yl cations: a DFT study. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Sayyed FB, Suresh CH, Gadre SR. Appraisal of through-bond and through-space substituent effects via molecular electrostatic potential topography. J Phys Chem A 2010; 114:12330-3. [PMID: 21043490 DOI: 10.1021/jp107689z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Through-bond (TB) and through-space (TS) substituent effects in substituted alkyl, alkenyl, and alkynyl arenes are quantified separately using molecular electrostatic potential (MESP) topographical analysis. The deepest MESP point over the aromatic ring (V(min)) is considered as a probe for monitoring these effects for a variety of substituents. In the case of substituted alkyl chains, the TS effect (79.6%) clearly dominates the TB effect, whereas in the unsaturated analogues the TB effect (∼55%) overrides the TS effect.
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Affiliation(s)
- Fareed Bhasha Sayyed
- Computational Modeling and Simulation Section, National Institute for Interdisciplinary Science and Technology (CSIR), Trivandrum 695019, India
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23
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Campanelli AR, Domenicano A, Piacente G, Ramondo F. Electronic Substituent Effects in Bicyclo[1.1.1]pentane and [n]Staffane Derivatives: A Quantum Chemical Study Based on Structural Variation. J Phys Chem A 2010; 114:5162-70. [DOI: 10.1021/jp909530u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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24
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Kolakowski RV, Williams LJ. Stereoinduction by distortional asymmetry. Nat Chem 2010; 2:303-7. [PMID: 21124512 DOI: 10.1038/nchem.577] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 01/19/2010] [Indexed: 11/09/2022]
Abstract
Stereoselective chemical synthesis requires the two faces of a π bond to be differentiated. Theoretically sound qualitative models for understanding stereoinduction seem to break down in sterically unbiased cyclic systems. Presented here as the distortional asymmetry model is new insight that identifies circumstances where distortional ground state contributions are highly asymmetric and thereby contribute significantly to face selectivity. Out-of-plane distortional potential calculations, transition state calculations and molecular orbital analysis agree with experimental data that cannot otherwise be attributed to steric, torsion, polar or emergent transition state stabilizing effects. The model is readily understood in terms of reaction theory. The explanatory power of the model is also discussed.
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Affiliation(s)
- Robert V Kolakowski
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08903, USA
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25
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Adcock W. Transmission of polar substituent effects across the cubane ring system:19F substituent chemical shifts (SCS) of 4-substituted (X) cub-1-yl fluorides revisited. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1560] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fraschetti C, Novara FR, Filippi A, Speranza M, Trout NA, Adcock W, Marcantoni E, Renzi G, Roselli G, Marcolini M. Gas-phase facial diastereoselectivity of equatorial and axial 4-chloro-adamant-2-yl cations. J Org Chem 2009; 74:5135-44. [PMID: 19719249 DOI: 10.1021/jo9004298] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The acid-catalyzed addition of CH3(18)OH to 2-methylene-adamantanes bearing a chlorine atom in the 4-equatorial (1e) or 4-axial (1a) position has been investigated in the gas phase, at 760 Torr, in the 40-120 degrees C temperature range. Two different experimental approaches were employed: (1) by adding neutral CH3(18)OH to the 2-methyl-4-Cl-adamant-2-yl cation, generated by protonation of the corresponding 2-methylene-4-Cl-adamantane (the extracomplex reaction) and (2) by reaction of 2-methylene-4-Cl-adamantane with CH3(18)OH2+, generated by methylation of H2(18)O (the intracomplex reaction). The crucial role of the nature of the noncovalent intermediates involved along the reaction coordinates emerges from the difference between the results obtained in the extracomplex and intracomplex reactions for both substrates investigated. The kinetic and stereochemical results indicate that the 4-Cl substituent plays a different role depending on its equatorial or axial orientation. Examination of the experimental results in the light of MP2/6-31G* theoretical calculations provides important information about the intrinsic factors governing the facial diastereoselectivity of trigonal carbocations. The effects due to differential face solvation phenomena emerge from the comparison of the present gas-phase results with those obtained from strictly related studies in solution.
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Affiliation(s)
- Caterina Fraschetti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma La Sapienza, P.le A. Moro, 5, Roma 00185, Italy
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27
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Suzuki Y, Kaneno D, Tomoda S. Theoretical Study on the Mechanism and Diastereoselectivity of NaBH4 Reduction. J Phys Chem A 2009; 113:2578-83. [DOI: 10.1021/jp809966u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yasumitsu Suzuki
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Daisuke Kaneno
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Shuji Tomoda
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
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28
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Barboni L, Filippi A, Fraschetti C, Giuli S, Marcolini M, Marcantoni E. Substituent stereochemistry effects on diastereoselective methylation reaction of 4-chloroadamantan-2-ones. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.07.181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Suzuki Y, Kaneno D, Miura M, Tomoda S. Solvent effects on the diastereoselection in LiAlH4 reduction of α-substituted ketones. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Goldsmith RH, Vura-Weis J, Scott AM, Borkar S, Sen A, Ratner MA, Wasielewski MR. Unexpectedly Similar Charge Transfer Rates through Benzo-Annulated Bicyclo[2.2.2]octanes. J Am Chem Soc 2008; 130:7659-69. [DOI: 10.1021/ja8004623] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Randall H. Goldsmith
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Josh Vura-Weis
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Amy M. Scott
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sachin Borkar
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Ayusman Sen
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Mark A. Ratner
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Michael R. Wasielewski
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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31
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Lampkins A, Li Y, Al Abbas A, Abboud K, Ghiviriga I, Castellano R. Assessable Consequences of Through-Bond Donor–Acceptor Interactions in β-Aminoketones. Chemistry 2008; 14:1452-63. [DOI: 10.1002/chem.200701220] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Zhou L, Alker A, Ruf A, Wang X, Chiu FCK, Morizzi J, Charman SA, Charman WN, Scheurer C, Wittlin S, Dong Y, Hunziker D, Vennerstrom JL. Characterization of the two major CYP450 metabolites of ozonide (1,2,4-trioxolane) OZ277. Bioorg Med Chem Lett 2008; 18:1555-8. [PMID: 18262417 DOI: 10.1016/j.bmcl.2008.01.087] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 01/23/2008] [Accepted: 01/25/2008] [Indexed: 11/25/2022]
Abstract
The antimalarial synthetic ozonide OZ277 (RBx11160) was hydroxylated by human liver microsomes at the distal bridgehead carbon atoms of the spiroadamantane substructure to form two carbinol metabolites devoid of antimalarial activity.
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Affiliation(s)
- Lin Zhou
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198, USA
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33
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Mello R, Royo J, Andreu C, Báguena-Añó M, Asensio G, González-Núñez ME. On the Reactivity of C(sp3)–H σ-Bonds: Oxygenation with Methyl(trifluoromethyl)dioxirane. European J Org Chem 2008. [DOI: 10.1002/ejoc.200700773] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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34
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Fraschetti C, Novara FR, Filippi A, Trout NA, Adcock W, Sorensen TS, Speranza M. Gas-Phase Diastereoselectivity of Secondary 5-Substituted (X)-Adamant-2-yl (X = F, Si(CH3)3) Cations. J Org Chem 2007; 72:4077-83. [PMID: 17465569 DOI: 10.1021/jo0702140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Secondary 5-X-adamant-2-yl cations IX (X = F, Si(CH3)3) have been generated in the gas phase (total pressure = 760 Torr) from protonation-induced defluorination of epimeric 2-F-5-X-adamantanes 1X and their kinetic diastereoselectivity toward CH318OH investigated in the 40-160 degrees C range. The experimental results indicate that the facial selectivity of IX is insensitive to the composition of the starting 1X epimers as well as to the presence and the concentration of a powerful base (N(C2H5)3). This kinetic picture, supported by B3LYP/6-31G* calculations, is consistent with a single stable pyramidalized structure for IX, that is, (Z)-5-F-adamant-2-yl (I(Z)F) and (E)-5-Si(CH3)3-adamant-2-yl cations (I(E)Si). The temperature dependence of the IX diastereoselectivity lends support to the intermediacy of noncovalent adducts [IX*CH318OH], characterized by a specific C2-H+...O18(H)CH3 hydrogen bonding interaction. Their conversion to the covalently bonded O-methylated (Z)- (II(Z)X) and (E)-5-X-adamantan-2-ols (II(E)X; X = F, Si(CH3)3) is governed by activation parameters, whose magnitude depends on the specific IX face accommodating CH318OH. The gas-phase diastereoselectivity of IX toward CH318OH is compared to that exhibited in related gas-phase and solution processes. The emerging picture indicates that the factors determining the diastereoselectivity of IX toward simple nucleophiles in the gaseous and condensed media are completely different.
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Affiliation(s)
- Caterina Fraschetti
- Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Sapienza Università di Roma, 00185 Roma, Italy
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35
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Campanelli AR, Domenicano A, Ramondo F. Polar Effects and Structural Variation in 4-Substituted 1-Phenylbicyclo[2.2.2]octane Derivatives: A Quantum Chemical Study. J Phys Chem A 2006; 110:10122-9. [PMID: 16913687 DOI: 10.1021/jp0621979] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The transmission of polar effects through the bicyclo[2.2.2]octane framework has been investigated by ascertaining how the geometry of a phenyl group at a bridgehead position is affected by a variable substituent at the opposite bridgehead position. We have determined the molecular structure of several Ph-C(CH(2)-CH(2))(3)C-X molecules (where X is a charged or dipolar substituent) from HF/6-31G and B3LYP/6-311++G molecular orbital calculations and have progressively replaced each of the three -CH(2)-CH(2)- bridges by a pair of hydrogen atoms. Thus the bicyclo[2.2.2]octane derivatives were changed first into cyclohexane derivatives in the boat conformation, then into n-butane derivatives in the anti-syn-anti conformation, and eventually into assemblies of two molecules, Ph-CH(3) and CH(3)-X, appropriately oriented and kept at a fixed distance. For each variable substituent the deformation of the benzene ring relative to X = H remains substantially the same even when the substituent and the phenyl group are no longer connected by covalent bonds. This provides unequivocal evidence that long-range polar effects in bicyclo[2.2.2]octane derivatives are actually field effects, being transmitted through space rather than through bonds. Varying the substituent X in a series of Ph-C(CH(2)-CH(2))(3)C-X molecules gives rise to geometrical variation (relative to X = H) not only in the benzene ring but also in the bicyclo[2.2.2]octane cage. The two deformations are poorly correlated. The rather small deformation of the benzene ring correlates well with traditional measures of long-range polar effects in bicyclo[2.2.2]octane derivatives, such as sigma(F) or sigma(I) values. The much larger deformation of the bicyclo[2.2.2]octane cage is controlled primarily by the electronegativity of X, similar to deformation of the benzene ring in Ph-X molecules. Thus the field and electronegativity effects of the substituent are well separated and can be studied simultaneously, as they act on different parts of the molecular skeleton.
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36
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Mühlthau F, Stadler D, Goeppert A, Olah GA, Prakash GKS, Bach T. Chiral α-Branched Benzylic Carbocations: Diastereoselective Intermolecular Reactions with Arene Nucleophiles and NMR Spectroscopic Studies. J Am Chem Soc 2006; 128:9668-75. [PMID: 16866519 DOI: 10.1021/ja062102g] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chiral benzylic alcohols 1-6 were prepared and subjected to S(N)1-type displacement reactions with various arene nucleophiles in acidic medium. Under optimized conditions (HBF(4).OEt(2), CH(2)Cl(2), -78 degrees C --> r.t.) the corresponding 1,1-diarylalkanes 11-18 and 20 were obtained in good chemical yields (48-99%). The facial diastereoselectivity of the reaction is high (d.r. = 91/9-97/3) when the substrate bears a stereogenic carbon center -CHtBuMe in the alpha-position to the electrophilic carbon atom. If the starting material was enantiomerically pure, no significant racemization was observed (94% ee --> 92% ee). The reactions proceed stereoconvergently as demonstrated by the conversion of the separated diastereoisomers syn-1a and anti-1a in separate reactions to the same product syn-11 (d.r. = 97/3). Further evidence for long-lived chiral benzylic carbocations as reaction intermediates was obtained from NMR studies in superacidic medium. The chiral cation 24 was generated in SO(2)ClF as the solvent at -70 degrees C employing SbF(5) as the Lewis acid and characterized by its (1)H and (13)C NMR spectra. NOE measurements suggest a preferred conformation in which the diastereotopic faces of the cation are differentiated by the two carbon substituents R and Me at the stereogenic carbon center in the alpha-position. The hypothesis is further supported by the observation that the diastereoselectivity of the substitution reaction decreases if the bulky tert-butyl (R = tBu) substituent in the substrate 1a is replaced by a smaller ethyl group (2a, R = Et).
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Affiliation(s)
- Friedrich Mühlthau
- Lehrstuhl für Organische Chemie I, Technische Universität München, D-85747 Garching, Germany
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37
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Lawes DJ, Darwish TA, Clark T, Harper JB, Ball GE. A Rhenium–Cyclohexane Complex with Preferential Binding of Axial CH Bonds: A Probe into the Relative Ability of CH, CD, and CC Bonds as Hyperconjugative Electron Donors? Angew Chem Int Ed Engl 2006; 45:4486-90. [PMID: 16770822 DOI: 10.1002/anie.200600313] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Douglas J Lawes
- School of Chemistry, University of New South Wales, Sydney NSW 2052, Australia
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38
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Lawes DJ, Darwish TA, Clark T, Harper JB, Ball GE. A Rhenium–Cyclohexane Complex with Preferential Binding of Axial CH Bonds: A Probe into the Relative Ability of CH, CD, and CC Bonds as Hyperconjugative Electron Donors? Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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39
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Moraleda D, Ollivier C, Santelli M. Manifestation of stereoelectronic effects on the calculated carbon–nucleophile bond lengths in nucleophilic addition to sterically unbiased ketones. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.05.180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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40
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Adcock W, Graton J, Laurence C, Luçon M, Trout N. Three-centre hydrogen bonding in the complexes ofsyn-2,4-difluoroadamantane with 4-fluorophenol and hydrogen fluoride. J PHYS ORG CHEM 2005. [DOI: 10.1002/poc.813] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Adcock W, Baran Y, Filippi A, Speranza M, Trout NA. Polar Substituent Effects in the Bicyclo[1.1.1]pentane Ring System: Acidities of 3-Substituted Bicyclo[1.1.1]pentane-1-carboxylic Acids. J Org Chem 2005; 70:1029-34. [PMID: 15675864 DOI: 10.1021/jo040236b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Experimental gas-phase acidities are reported for a series of 3-substituted (X) bicyclo [1.1.1]pent-1-yl carboxylic acids (1, Y = COOH). A comparison with available calculated data (MP2/6-311++G**// B3LYP/6-311+G**) reveals good agreement. The relative substituent effects are shown to be adequately described by a much lower level of theory (B3LYP/6-31+G*). Various correlations are presented which clearly point to polar field effects as being the origin of the relative acidities.
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Affiliation(s)
- William Adcock
- School of Chemistry, Physics, and Earth Sciences, The Flinders University of South Australia, Adelaide, Australia 5001.
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42
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Chu JH, Li WS, Chao I, Chung WS. Face selectivity in the reactions of 2,4-disubstituted adamantanes and their modification by inclusion in β-cyclodextrin solutions. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.07.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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43
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Lenoir D, Hertkorn N, Chiappe C. Synthesis and characterization of the syn-bromonium ion of 4-equ chloroadamantylidenadamantane, towards a chiral bromination reagent. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.01.069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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44
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Adcock W, Trout NA, Vercoe D, Taylor DK, Shiner VJ, Sorensen TS. Solvolysis of (Z)-5-trimethylstannyl 2-adamantyl p-bromobenzenesulfonate: mechanistic implications of a record-breaking secondary alpha-deuterium kinetic isotope effect for an SN1 substrate. J Org Chem 2003; 68:5399-402. [PMID: 12816508 DOI: 10.1021/jo0300892] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The secondary alpha-deuterium kinetic isotope effect (alpha-kie) for the solvolysis of (Z)-5-trimethylstannyl 2-adamantyl p-bromobenzenesulfonate in 97% w/w aqueous 2,2,2-trifluoroethanol (97T) at 25 degrees C has been measured (k(H)/k(D) = 1.33). The alpha-kie is abnormally high compared to the value of 1.23 for the corresponding limiting S(N)1 solvolysis of 2-adamantyl p-bromobenzenesulfonate, which proceeds via an extended ion-pair mechanism. A novel mechanism for the solvolysis of the tin compound is proposed that accommodates not only the high alpha-kie but also the absence of internal return.
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Affiliation(s)
- William Adcock
- School of Chemistry, Physics, and Earth Sciences, Flinders University of South Australia, Adelaide, SA 5001, Australia.
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45
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Sproviero EM, Burton G. Stereoelectronic Interactions and Molecular Properties. An NBO-Based Study of Uracil. J Phys Chem A 2003. [DOI: 10.1021/jp0271763] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eduardo M. Sproviero
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, (C1428EGA) Buenos Aires, Argentina
| | - Gerardo Burton
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, (C1428EGA) Buenos Aires, Argentina
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Martínez AG, Vilar ET, Barcina JO, De La Moya Cerero S. Comprehensive study of the methyl effect on the solvolysis rates of bridgehead derivatives. J Am Chem Soc 2002; 124:6676-85. [PMID: 12047187 DOI: 10.1021/ja016583+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effect of a bridgehead methyl group on the hydride ion affinity in the gas phase of bicyclo[1.1.1]pent-1-yl (1+), 1-norbornyl (3+), cubyl (5+), 1-adamantyl (7+), bicyclo[2.2.2]oct-1-yl (9+),and bicyclo[3.1.1]hept-1-yl (11+) cations has been studied using density functional theory and ab initio methods. It is concluded that the methyl group always increases the stability of the substituted cations. The effect of the solvent on the stability of methyl-substituted cations in relation to the unsubstituted cations has been studied using the polarizable continuum model of the self-consistent reaction field theory. In the case of rearranging cations, the nucleophilic assistance of the solvent is determined by means of the interaction energy of the corresponding water complexes. It is concluded that the solvent causes the relative stabilization of the parent cations. As a consequence, most of the methyl-substituted bridgehead derivatives show a lower solvolysis rate than the corresponding unsubstituted compounds. A nonqualitative explanation of the methyl effect on the relative stability of bridgehead cations in both gas phase and solution is given for the first time. The ratios of solvolysis products in the case of rearranging bridgehead cations have also been computed from the relative stability of the intermediate water complexes.
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Affiliation(s)
- Antonio García Martínez
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
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47
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Nolan EM, Linck RG. Through-Space Charge and Dipolar Effects in Substituted Ethanes and 1,1,1-Trifluoroethanes. J Phys Chem A 2001. [DOI: 10.1021/jp012969v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elizabeth M. Nolan
- The Chemistry Department, Smith College, Northampton, Massachusetts 01063-0100
| | - R. G. Linck
- The Chemistry Department, Smith College, Northampton, Massachusetts 01063-0100
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48
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Liu JT, Jang YJ, Shih YK, Hu SR, Chu CM, Yao CF. Novel synthesis of alkenes via triethylborane-induced free-radical reactions of alkyl iodides and beta-nitrostyrenes. J Org Chem 2001; 66:6021-8. [PMID: 11529727 DOI: 10.1021/jo010213m] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions of (E)-beta-nitrostyrenes 1 and triethylborane 2 or tricyclohexylborane 4 in THF solution at room temperature in the presence of oxygen in the air as radical initiator generate high yields of trans-alkenes (E)-3 or (E)-5. Medium to high yields of different (E)-alkenes (E)-5, 7, 10, 12, and 14 also can be prepared when 1 reacts with different radicals, prepared from secondary alkyl iodides 6 and 8 or tertiary alkyl iodides 9, 11, and 13, in the presence of 2 and air as radical initiator. The generation of the only product (E)-alkenes can be explained by the generation of the benzylic radical A and/or B as the intermediate only and the mechanism is similar to Scheme 1. Both (E)- and (Z)-16a-c are generated when (E)- and (Z)-15a-c are used to react with adamantyl radical under similar conditions. Only (Z)-16d was observed when either (E)- or (Z)-15d was used to react with adamantyl radical. The generation of the (E)- and/or (Z)-alkenes can be explained by the free rotation of the A and/or B to generate A' and/or B' and vice versa, and the mechanism is proposed to be a free-radical reaction via NO2/alkyl substitution and is shown as Scheme 2.
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Affiliation(s)
- J T Liu
- Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei, Taiwan 116, Republic of China
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49
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Avalos M, Babiano R, Cintas P, Clemente FR, Gordillo R, Jiménez JL, Palacios JC. Synergic effect of vicinal stereocenters in [3 + 2] cycloadditions of carbohydrate azadipolarophiles and mesoionic dipoles: origin of diastereofacial selectivity. J Org Chem 2001; 66:5139-45. [PMID: 11463267 DOI: 10.1021/jo015654k] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The intermolecular [3 + 2] cycloaddition of carbohydrate-derived 1,2-diaza-1,3-butadienes and 1,3-thiazolium-4-olates provides a conceptual basis for the problem of diastereofacial preference in the acyclic series of unsaturated sugars. Experimental results employing a side chain of D-arabino configuration have shown the stereodifferentiation exerted by the first stereogenic center that renders the Re,Re face of the acyclic sugar-chain azadiene eligible for cycloaddition (J. Org. Chem. 2000, 65, 5089). The results of the present work, now utilizing an alternative framework of D-lyxo configuration, evidence the discriminating power of the second stereogenic carbon, which induces the preferential approach to the Re,Si face of the heterocyclic dipole. This scheme of face selectivity is also grounded in theoretical calculations at a semiempirical level. In addition to dihydrothiophenes, which are the expected products of the [3 + 2] cycloaddition, bicyclic systems based on dihydrothieno[2,3-c]piperidine skeleton can also be obtained.
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Affiliation(s)
- M Avalos
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, E-06071 Badajoz, Spain.
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Nolan EM, Linck RG. An Exploration of Long Range Electronic Effects in Substituted Alkanes. J Phys Chem A 2001. [DOI: 10.1021/jp010833r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - R. G. Linck
- Chemistry Department, Smith College, Northampton, Massachusetts 01063
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