1
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Ovais Dar M, Kapse RY, Dubey G, Singh T, Thiruvenkatam V, Bharatam PV. Electronic Structure Analysis and Synthesis of Nitroso
N
‐Heterocyclic Imines. ChemistrySelect 2022. [DOI: 10.1002/slct.202203613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Mohammad Ovais Dar
- Department of Medicinal Chemistry National Institute of Pharmaceutical Education and Research Sector 67, S.A.S. Nagar 160062 Punjab India
| | - Rahul Y. Kapse
- Department of Medicinal Chemistry National Institute of Pharmaceutical Education and Research Sector 67, S.A.S. Nagar 160062 Punjab India
| | - Gurudutt Dubey
- Department of Medicinal Chemistry National Institute of Pharmaceutical Education and Research Sector 67, S.A.S. Nagar 160062 Punjab India
- Current address Discipline of Chemistry Indian Institute of Technology Gandhinagar Palaj Gandhinagar 382355 Gujarat India
| | - Tejender Singh
- Department of Medicinal Chemistry National Institute of Pharmaceutical Education and Research Sector 67, S.A.S. Nagar 160062 Punjab India
- Current address Tata Institute of Fundamental Research (TIFR) Hyderabad Gopanpally Hyderabad 500046 Telangana India
| | - Vijay Thiruvenkatam
- Discipline of Biological Engineering Indian Institute of Technology Gandhinagar Palaj Gandhinagar 382355 Gujarat India
| | - Prasad V. Bharatam
- Department of Medicinal Chemistry National Institute of Pharmaceutical Education and Research Sector 67, S.A.S. Nagar 160062 Punjab India
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2
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Zhuo X, Zheng L, Zou X, Zhong Y, Guo W. Metal-Free Temperature-Controlled Intermolecular [3 + 2] Annulation to Access Benzo[ d]thiazole-2(3 H)-thiones and Benzo[ d]thiazol-2(3 H)-ones. J Org Chem 2022; 87:10467-10475. [PMID: 35820197 DOI: 10.1021/acs.joc.2c01060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A facile access to benzo[d]thiazole-2(3H)-thiones and benzo[d]thiazol-2(3H)-ones has been developed through a temperature-controlled intermolecular [3 + 2] annulation of N,N-disubstituted arylhydrazines with CS2 in the presence of DMSO. This protocol can obviate the prefunctionalization of the starting materials. This direct C-S/C-N bond formation reaction was performed in the absence of any external catalysts, transition metals, bases, ligands, and oxidants with high step economy.
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Affiliation(s)
- Xiaoya Zhuo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Lvyin Zheng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Xiaoying Zou
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yumei Zhong
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Wei Guo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
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3
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Chen J, Zhou X, Yuan T. Highly Efficient and Practical Method for Synthesis of 2,2′-Azino-Bis(3-Ethyl-benzothiazoline-6-Sulfonic Acid) (ABTS) and Its Diammonium Salt. SYNTHETIC COMMUN 2014. [DOI: 10.1080/00397911.2014.951897] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Junmin Chen
- a Department of Chemistry , Jiangxi Normal University , Nanchang , China
| | - Xiaomeng Zhou
- a Department of Chemistry , Jiangxi Normal University , Nanchang , China
| | - Tangjun Yuan
- a Department of Chemistry , Jiangxi Normal University , Nanchang , China
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4
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Sandhiya L, Kolandaivel P, Senthilkumar K. Depletion of atmospheric ozone by nitrogen dioxide: a bifurcated reaction pathway. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1382-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Tskhovrebov AG, Vuichoud B, Solari E, Scopelliti R, Severin K. Adducts of Nitrous Oxide and N-Heterocyclic Carbenes: Syntheses, Structures, and Reactivity. J Am Chem Soc 2013; 135:9486-92. [DOI: 10.1021/ja4030287] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander G. Tskhovrebov
- Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Basile Vuichoud
- Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Euro Solari
- Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kay Severin
- Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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6
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Siebert MR, Manikandan P, Sun R, Tantillo DJ, Hase WL. Gas-Phase Chemical Dynamics Simulations on the Bifurcating Pathway of the Pimaradienyl Cation Rearrangement: Role of Enzymatic Steering in Abietic Acid Biosynthesis. J Chem Theory Comput 2012; 8:1212-22. [DOI: 10.1021/ct300037p] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Matthew R. Siebert
- Department of Chemistry
and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Paranjothy Manikandan
- Department of Chemistry
and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Rui Sun
- Department of Chemistry
and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Dean J. Tantillo
- Department of Chemistry, University of California—Davis, Davis, California
95616, United States
| | - William L. Hase
- Department of Chemistry
and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
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7
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Tskhovrebov AG, Solari E, Wodrich MD, Scopelliti R, Severin K. Sequential N–O and N–N Bond Cleavage of N-Heterocyclic Carbene-Activated Nitrous Oxide with a Vanadium Complex. J Am Chem Soc 2012; 134:1471-3. [DOI: 10.1021/ja210976a] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Alexander G. Tskhovrebov
- Institut des Sciences
et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne,
Switzerland
| | - Euro Solari
- Institut des Sciences
et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne,
Switzerland
| | - Matthew D. Wodrich
- Institut des Sciences
et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne,
Switzerland
| | - Rosario Scopelliti
- Institut des Sciences
et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne,
Switzerland
| | - Kay Severin
- Institut des Sciences
et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne,
Switzerland
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8
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Tskhovrebov AG, Solari E, Wodrich MD, Scopelliti R, Severin K. Covalent Capture of Nitrous Oxide by N-Heterocyclic Carbenes. Angew Chem Int Ed Engl 2011; 51:232-4. [DOI: 10.1002/anie.201106589] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Indexed: 11/07/2022]
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9
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Tskhovrebov AG, Solari E, Wodrich MD, Scopelliti R, Severin K. Covalent Capture of Nitrous Oxide by N-Heterocyclic Carbenes. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201106589] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Greer EM, Lavinda O. Theoretical Study of the Bergman Cyclization of 2,3-Diethynyl-1-nitrotropylium Ion: Formation of a Nitroxide Radical Amenable to EPR Detection for Biological Applications. J Org Chem 2010; 75:8650-3. [DOI: 10.1021/jo101451d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Edyta M. Greer
- Department of Natural Sciences, Baruch College, 17 Lexington Avenue, New York, New York 10010, United States
| | - Olga Lavinda
- Department of Natural Sciences, Baruch College, 17 Lexington Avenue, New York, New York 10010, United States
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11
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Souto JA, Pérez M, Silva López C, Álvarez R, Torrado A, de Lera AR. Competing Thermal Electrocyclic Ring-Closure Reactions of (2Z)-Hexa-2,4,5-trienals and Their Schiff Bases. Structural, Kinetic, and Computational Studies. J Org Chem 2010; 75:4453-62. [DOI: 10.1021/jo100558p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- José A. Souto
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - Martín Pérez
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - Carlos Silva López
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - Rosana Álvarez
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - Alicia Torrado
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - Angel R. de Lera
- Departamento de Química Orgánica, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
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12
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Burke LA, Butler RN. Computational Investigation of Rearrangements in Huisgen Cycloadducts of Azolium N-Dicyanomethanide 1,3-Dipoles with Alkynes: A Mechanistic Panoply. J Org Chem 2009; 74:5199-210. [DOI: 10.1021/jo900063n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Luke A. Burke
- Chemistry Department, Rutgers University, Camden, New Jersey 08102
| | - Richard N. Butler
- Chemistry Department, National University of Ireland, Galway, Ireland
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13
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Theoretical study on the thermal dehydrochlorination of model compounds for poly(vinyl chloride). ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2008.10.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Ess D, Wheeler S, Iafe R, Xu L, Çelebi-Ölçüm N, Houk K. Bifurkationen auf den Potentialenergiehyperflächen organischer Reaktionen. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800918] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Zhang C, Wang X, Liu L, Wang Y, Peng X. Modeling the spontaneous initiation of the polymerization of methyl methacrylate. J Mol Model 2008; 14:1053-64. [DOI: 10.1007/s00894-008-0344-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
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16
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Ess DH, Wheeler SE, Iafe RG, Xu L, Çelebi-Ölçüm N, Houk KN. Bifurcations on potential energy surfaces of organic reactions. Angew Chem Int Ed Engl 2008; 47:7592-601. [PMID: 18767086 PMCID: PMC2790825 DOI: 10.1002/anie.200800918] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A single transition state may lead to multiple intermediates or products if there is a post-transition-state reaction pathway bifurcation. These bifurcations arise when there are sequential transition states with no intervening energy minimum. For such systems, the shape of the potential energy surface and dynamic effects, rather than transition-state energetics, control selectivity. This Minireview covers recent investigations of organic reactions exhibiting reaction pathway bifurcations. Such phenomena are surprisingly general and affect experimental observables such as kinetic isotope effects and product distributions.
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Affiliation(s)
| | | | | | | | | | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095, (USA), (+ 1) 310-206-1843, E-mail:
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17
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López CS, Faza ON, de Lera AR. Characterization of the Switch in the Mechanism of an Intramolecular Diels−Alder Reaction. J Org Chem 2007; 73:467-73. [DOI: 10.1021/jo701962t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos Silva López
- Departamento de Quimica Organica, Universidade de Vigo, Lagoas Marcosende, 36310 Vigo, Galicia, Spain, and Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431
| | - Olalla Nieto Faza
- Departamento de Quimica Organica, Universidade de Vigo, Lagoas Marcosende, 36310 Vigo, Galicia, Spain, and Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431
| | - Angel R. de Lera
- Departamento de Quimica Organica, Universidade de Vigo, Lagoas Marcosende, 36310 Vigo, Galicia, Spain, and Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431
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19
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da Silva G, Kennedy EM, Dlugogorski BZ. Ab Initio Study of Bonding between Nucleophilic Species and the Nitroso Group. J Phys Chem A 2007; 111:1300-6. [PMID: 17266284 DOI: 10.1021/jp054266+] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bonding between anionic nucleophiles and the nitroso group has been studied in the common nitrosating agents nitroso chloride (ONCl), nitroso bromide (ONBr), nitroso thiocyanate (ONSCN), and dinitrogen trioxide (N2O3) in aqueous solution. A variety of theoretical methods were employed, including ab initio, density functional theory (DFT), and composite theoretical techniques, with solvent effects described using the polarizable continuum model (PCM). Experimental nitroso bond heterolytic dissociation free energies were accurately reproduced with a number of composite theoretical methods, the most successful being CBS-Q and G2MP2, with average errors of 3.1 and 3.4 kJ mol(-1), respectively. Using the MP2 and B3LYP methods, calculations were made with correlation consistent basis sets up to quadruple-zeta, extrapolated to the complete basis set (CBS) limit. The MP2/CBS calculations were accurate to around 10 kJ mol(-1), while the B3LYP/CBS calculations routinely overpredicted experimental bond free energies by ca. 40 kJ mol(-1). It is therefore highly recommended that B3LYP energies are not used for nitroso compounds, although other results demonstrate that the B3LYP method provides a good account of nitroso compound geometries, frequencies, and entropies. Single-point CBS energy calculations using MP2/aug-cc-pVQZ geometries and frequencies showed that the MP4(SDTQ) and QCISD(T) methods provide a slight improvement over MP2 at the CBS limit, although the inclusion of triple excitations is necessary to achieve this improvement in accuracy. Enthalpy-entropy compensation was also discovered, with an average isoequilibrium temperature of 825 K. This relatively large isoequilibrium temperature indicates that enthalpic effects dominate over entropic ones.
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Affiliation(s)
- Gabriel da Silva
- Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308, Australia
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20
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da Silva G, Kennedy EM, Dlugogorski BZ. Nucleophilic reactivity of aniline derivatives towards the nitroso group. J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1142] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Silva López C, Nieto Faza O, Alvarez R, de Lera AR. Cycloisomerization of Activated (2E,4Z)-Heptatrienoate and Its Relevance to Crispatene (Bio)synthesis. A Case of Concerted and Stepwise Uncertainty. J Org Chem 2006; 71:4497-501. [PMID: 16749779 DOI: 10.1021/jo0603274] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A single transition structure was located on the potential energy surface of the cycloisomerization of protic and Lewis acid activated (2E,4Z)-heptatrienal and the corresponding methyl ester to provide the bicyclo[3.1.0]hexene derivatives, the central skeleton of the crispatene natural products. A two-dimensional scan of the C-C bond-forming reactions revealed a barrierless cyclopropane closure following the pentadienyl cycloisomerization, with preservation of the stereochemical information.
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Affiliation(s)
- Carlos Silva López
- Departamento de Química Organica, Facultade de Química, Universidade de Vigo, Lagoas Marcosende, E-36310, Vigo, Galicia, Spain
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Krogstad DA, Cho J, DeBoer AJ, Klitzke JA, Sanow WR, Williams HA, Halfen JA. Platinum (II) and palladium (II) 1,3,5-triaza-7-phosphaadamantane (PTA) complexes as intramolecular hydroamination catalysts in aqueous and organic media. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2005.08.028] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Sadasivam DV, Prasad E, Flowers RA, Birney DM. Stopped-Flow Kinetics of Tetrazine Cycloadditions; Experimental and Computational Studies toward Sequential Transition States. J Phys Chem A 2005; 110:1288-94. [PMID: 16435789 DOI: 10.1021/jp0534075] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Diels-Alder cycloadditions of tetrazines (1) with alkynes (2) are expected to give bicyclic adducts (3). Kinetic measurements of the cycloadditions of 1a and 1b with 2a give DeltaG(++) = 19.2 +/- 1.0 and 11.5 +/- 1.2 kcal/mol, respectively. Stopped-flow UV studies on the reaction of 1b with 2a show an isosbestic point at 428 nm; this places an upper limit of 11.6 +/- 2.6 kcal/mol on DeltaG(++) for loss of N(2) from the putative bicyclic intermediate 3b. Calculations (B3LYP/6-31G(d,p) + ZPVE) of transition structures for the reaction of tetrazinediacid 1d with propynylamine 2c are consistent with the experimental results for the reaction of 1b with 2a. This and several related model systems reveal two interesting features of the calculated energy surfaces. First, there may be no barrier for the loss of nitrogen from structures 3 and thus there may be two sequential transition states. This also extends Berson's correlation of activation energy with reaction energy in pericyclic reactions to significantly lower barriers. Second, for the cycloaddition of 4e and 2c, there is neither an intermediate nor a transition state between TS3e and the final product 6e. It appears that the energy surface "turns a corner" in the vicinity of a structure resembling 5e. This is not a mathematically well-defined point but has chemical consequences in that the overall exothermicity of the reaction from 4e to 6e is not felt in TS3e.
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Affiliation(s)
- Dhandapani V Sadasivam
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA.
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Bornemann H, Wentrup C. Energy profiles for ketene cyclizations. Interconversion of 1,3-oxazin-6-ones, mesoionic 1,3-oxazinium olates and acylketenes, imidoylketenes, oxoketenimines, and cyclization products. J Org Chem 2005; 70:5862-8. [PMID: 16018679 DOI: 10.1021/jo050429e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The energy surface connecting oxazinium olates 9, several possible conformers of ketenes 10 and 11, and the final cyclization products 12, 13 and 14, as well as the isomeric 1,3-oxazine-6-ones 15, ring opening of the latter to N-acylimidoylketenes 16, and subsequent rearrangement of 16 to oxoketenimines 17, azetinones 18, and the cyclization products 19 and 20 are evaluated computationally at the B3LYP/6-31G and B3LYP/6-311+G//B3LYP/6-31G levels. The cyclizations of ketenes to oxazinium olates 9 and oxazines 15 have the characteristics of pseudopericyclic reactions. Plots of the energy vs internal reaction coordinate for the cyclization of transoid acylketenes such as 10 to 9 (via TS1) and 16 to 15 (via TS7) feature two inflection points and indicate that the part of the energy surface above the lower inflection points describe internal rotation of the acyl function in the ketene moiety, and the part below this point describes the cyclization of the cisoid ketene to the planar mesoionic oxazinium olate 9 or oxazinone 15. The 1,3-shifts of the OR group that interconvert ketenes 16 and ketenimines 17 via four-membered cyclic transition states TS8 behave similarly, the first portion (from the ketenimine side) of the activation barrier being due largely to internal rotation of substituents, and the top part being due to the 1,3-shift proper.
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Affiliation(s)
- Holger Bornemann
- Chemistry Building, School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Qld 4072, Australia
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25
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Silva MA, Goodman JM. Aziridinium ring opening: a simple ionic reaction pathway with sequential transition states. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.01.142] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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26
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Reinhold M, McGrady JE, Perutz RN. A comparison of C-F and C-H bond activation by zerovalent ni and pt: a density functional study. J Am Chem Soc 2004; 126:5268-76. [PMID: 15099111 DOI: 10.1021/ja0396908] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory indicates that oxidative addition of the C-F and C-H bonds in C6F6 and C6H6 at zerovalent nickel and platinum fragments, M(H2PCH2CH2PH2), proceeds via initial exothermic formation of an eta2-coordinated arene complex. Two distinct transition states have been located on the potential energy surface between the eta2-coordinated arene and the oxidative addition product. The first, at relatively low energy, features an eta3-coordinated arene and connects two identical eta2-arene minima, while the second leads to cleavage of the C-X bond. The absence of intermediate C-F or C-H sigma complexes observed in other systems is traced to the ability of the 14-electron metal fragment to accommodate the eta3-coordination mode in the first transition state. Oxidative addition of the C-F bond is exothermic at both nickel and platinum, but the barrier is significantly higher for the heavier element as a result of strong 5dpi-ppi repulsions in the transition state. Similar repulsive interactions lead to a relatively long Pt-F bond with a lower stretching frequency in the oxidative addition product. Activation of the C-H bond is, in contrast, exothermic only for the platinum complex. We conclude that the nickel system is better suited to selective C-F bond activation than its platinum analogue for two reasons: the strong thermodynamic preference for C-F over C-H bond activation and the relatively low kinetic barrier.
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Affiliation(s)
- Meike Reinhold
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
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27
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Freeman F, Cha C. Computational study of the chair-chair interconversion and stereoelectronic interactions in 1,2,3-trithiacyclo-hexane (1,2,3-trithiane). J PHYS ORG CHEM 2004. [DOI: 10.1002/poc.678] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ozkan I, Zora M. Transition Structures, Energetics, and Secondary Kinetic Isotope Effects for Cope Rearrangements of cis-1,2-Divinylcyclobutane and cis-1,2-Divinylcyclopropane: A DFT Study. J Org Chem 2003; 68:9635-42. [PMID: 14656088 DOI: 10.1021/jo035173w] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The minimum energy reaction paths and secondary kinetic isotope effects (KIE) for the Cope rearrangements of cis-1,2-divinylcyclobutane and cis-1,2-divinylcyclopropane obtained by (U)B3LYP calculations are reported. Both reactions proceed through endo-boatlike reaction paths, and have aromatic transition states. The predicted activation energies are in agreement with the experimental data. The reaction paths of the rearrangements are intervened by enantiomerization saddle points of the products (and the reactant in the case of divinylcyclobutane). The calculated KIEs are similar in the two systems, and consistent with the geometries of the transition structures. There is computational evidence that the isotope effect associated with the conversion of a pure sp(2) C-H bond into a pure sp(3) one might be the same in all molecules. The predicted KIEs agree with experiment for divinylcyclopropane, but not for divinylcyclobutane.
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Affiliation(s)
- Ilker Ozkan
- Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey.
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29
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Razus AC, Birzan L, Nae S, Surugiu MN, Cimpeanu V. Azulene-1-azo-2′-thiazoles. Synthesis and properties. J Heterocycl Chem 2003. [DOI: 10.1002/jhet.5570400607] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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30
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Silva MA, Pellegrinet SC, Goodman JM. A DFT study on the regioselectivity of the reaction of dichloropropynylborane with isoprene. J Org Chem 2003; 68:4059-66. [PMID: 12737591 DOI: 10.1021/jo026821z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This theoretical study deals with the reaction of isoprene and dichloropropynylborane. We report the results of the DFT calculations applied to the two processes involved, Diels-Alder cycloaddition and 1,4-alkynylboration. The boron influences both the chemoselectivity and the regioselectivity of this reaction through secondary orbital interactions (SOI hereafter) that give rise to transition structures with strong [4 atom + 3 atom] character. The "meta" regioselectivity observed experimentally for the reaction between 2-substituted 1,3-dienes and alkynyldihaloboranes has been explained as a result of the higher stabilization of these transition structures with "meta" orientation. Intrinsic reaction coordinate calculations were performed to determine connectivities and established the remarkable result that the geometrically very similar transition structures leading to both regioisomeric 1,4-alkynylboration products correspond to different pathways. For the "meta" orientation a direct alkynylboration of the diene through a concerted transition structure was found.
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Affiliation(s)
- María A Silva
- Department of Chemistry, University of Cambridge, Lensfield Road, UK
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31
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Freeman F, Le KT. A Computational Study of Conformations and Conformers of 1,3-Dithiane (1,3-Dithiacyclohexane). J Phys Chem A 2003. [DOI: 10.1021/jp0138633] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fillmore Freeman
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025
| | - Kelly Thuy Le
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025
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32
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Zhou C, Birney DM. Sequential transition States and the valley-ridge inflection point in the formation of a semibullvalene. Org Lett 2002; 4:3279-82. [PMID: 12227768 DOI: 10.1021/ol026595f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[structure: see text] Two sequential transition states are calculated at the B3LYP/6-31G(d,p) level for the deazetization of 3b. The intrinsic reaction coordinate for loss of nitrogen passes through a transition state and then a valley-ridge inflection point and ultimately leads to the transition state for the Cope rearrangement of semibullvalene 4b. The energetic and geometrical consequences are discussed.
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Affiliation(s)
- Chun Zhou
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061, USA
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33
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Saripinar E, Ozer Ilhan I, Akçamur Y. Reactions of a-Oxo Ketenes with Amides: Experimental Data and Semiempirical AM1 Molecular Orbital Calculations. HETEROCYCLES 2002. [DOI: 10.3987/com-02-9504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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