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Yang ZH, Wang Q, Zhuo S, Xu LP. Mechanistic Study on Palladium-Catalyzed Regioselective Oxidative Amination: Roles of Ammonium Salts. J Org Chem 2020; 85:6981-6991. [PMID: 32396725 DOI: 10.1021/acs.joc.0c00296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Anti-Markovnikov selective oxidative amination reaction with simple alkenes is particularly promising but challenging because of the inherent electronic effect of the alkene substrate which is in favor of the Markovnikov product. In a recently reported Pd-catalyzed anti-Markovnikov oxidative amination reaction, the addition of quaternary ammonium salts is shown to be critical. We performed a comprehensive DFT study to elucidate the reaction mechanism and the origin of the regioselectivity, as well as the roles of the ammonium salts. Our results show that without and with the ammonium salts the reaction mechanisms are different. Detailed analyses indicate that the steric effects account for the switch of regioselectivity. The roles of the quaternary ammonium salts have been elucidated: (1) Me4NOAc plays the role of base in deprotonating the phthalimide and allows the reaction to proceed through a trans-aminopalladation mechanism; (2) Me4NCl facilitates the thermodynamically favorable transformation of Pd(OAc)2 to the palladate ([Pd(AcO)2Cl2]2-), which lessens the polarity of the carbon-carbon double bond, minimizes the inherent electronic effects, and leads to a steric-effect-controlled reaction; (3) Me4NCl is essential in decreasing the activation barrier in the rate-determining ligand exchange step by Cl- acting as a better leaving group (compared to AcO-).
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Affiliation(s)
- Zhen-Hua Yang
- School of Chemistry and Chemical Engineering, Shandong University of Technology, 266 West Xincun Road, Zibo, 255000, P. R. China
| | - Qian Wang
- School of Chemistry and Chemical Engineering, Shandong University of Technology, 266 West Xincun Road, Zibo, 255000, P. R. China
| | - Shuping Zhuo
- School of Chemistry and Chemical Engineering, Shandong University of Technology, 266 West Xincun Road, Zibo, 255000, P. R. China
| | - Li-Ping Xu
- School of Chemistry and Chemical Engineering, Shandong University of Technology, 266 West Xincun Road, Zibo, 255000, P. R. China
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2
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Aucott BJ, Duhme-Klair AK, Moulton BE, Clark IP, Sazanovich IV, Towrie M, Hammarback LA, Fairlamb IJS, Lynam JM. Manganese Carbonyl Compounds Reveal Ultrafast Metal–Solvent Interactions. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00212] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Benjamin J. Aucott
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | | | - Benjamin E. Moulton
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Ian P. Clark
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, U.K
| | - Igor V. Sazanovich
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, U.K
| | - Michael Towrie
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, OX11 0QX, U.K
| | | | - Ian J. S. Fairlamb
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Jason M. Lynam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
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3
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Han J, Jean M, Roussel C, Moriwaki H, Soloshonok VA. Chromatographic approach to study the configurational stability of Ni(II) complexes of amino-acid Schiff bases possessing stereogenic nitrogen. Chirality 2019; 31:328-335. [PMID: 30702773 DOI: 10.1002/chir.23059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 01/17/2023]
Abstract
Herein, we disclose the design of a model Ni(II) complex of glycine Schiff base possessing single-nitrogen stereogenic center, which was successfully used for high-performance liquid chromatography (HPLC)-assisted assessment of its configurational stability. The major finding is that the configurational stability of the Ni(II)-coordinated nitrogen is profoundly dependent on the reaction conditions used, in particular the solvent, and can range from inconsequential (t½ less than 5 min) to virtually completely stable (t½ 90 y). The discovery reported in this study most likely to be of certain theoretical and synthetic value.
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Affiliation(s)
- Jianlin Han
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, China
| | - Marion Jean
- Aix-Marseille University, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Christian Roussel
- Aix-Marseille University, CNRS, Centrale Marseille, iSm2, Marseille, France
| | | | - Vadim A Soloshonok
- Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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4
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Zahn D. Exploring the Mechanisms of Reactions in Solution from Transition Path Sampling Molecular Dynamics Simulations. J Chem Theory Comput 2015; 2:107-14. [PMID: 26626385 DOI: 10.1021/ct0501755] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent advances in molecular dynamics simulations of rare reaction events and aggregation processes are reviewed. Therein the central focus is dedicated to employing the transition path sampling method to study reactions in solution. We describe systematic approaches for generating initial transition pathways and efficient strategies for computationally feasible exploration of further transition routes. The unprejudiced study of reaction mechanisms is illustrated for reactions in aqueous solution and other complex systems. Transition path sampling allows very detailed investigation of solvent effects. Apart from stabilization of reactant, transition, or product state ensembles, this also includes the role of the solvent as a heat bath and as a putative reaction partner. The latter issue is of particular importance for reactions in aqueous solutions, which involve proton-transfer steps that may be assisted by water molecules via the Grotthuss mechanism.
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Affiliation(s)
- Dirk Zahn
- Max-Planck Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, 01187 Dresden, Germany
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5
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Mullen RG, Shea JE, Peters B. Easy Transition Path Sampling Methods: Flexible-Length Aimless Shooting and Permutation Shooting. J Chem Theory Comput 2015; 11:2421-8. [DOI: 10.1021/acs.jctc.5b00032] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryan Gotchy Mullen
- Department of Chemical Engineering, ‡Department of Chemistry & Biochemistry, §Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Joan-Emma Shea
- Department of Chemical Engineering, ‡Department of Chemistry & Biochemistry, §Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Baron Peters
- Department of Chemical Engineering, ‡Department of Chemistry & Biochemistry, §Department of Physics, University of California, Santa Barbara, California 93106, United States
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Wieszczycka K, Zembrzuska J. Photodegradation and by-products identification of commercial extractant Cyanex 302. J Radioanal Nucl Chem 2013. [DOI: 10.1007/s10967-013-2849-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Zahn D. Tackling time-reversibility in transition path sampling molecular dynamics simulations. MOLECULAR SIMULATION 2012. [DOI: 10.1080/08927022.2011.614241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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8
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Zahn D. Modeling martensic transformations in crystalline solids: validity and redesign of geometric approaches. ACTA ACUST UNITED AC 2011. [DOI: 10.1524/zkri.2011.1368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Rowley CN, Woo TK. New shooting algorithms for transition path sampling: Centering moves and varied-perturbation sizes for improved sampling. J Chem Phys 2009; 131:234102. [DOI: 10.1063/1.3274203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Liu G, Chen D, Jiao X. Direct solution synthesis of corundum-type In2O3 : effects of precursors on products. CrystEngComm 2009. [DOI: 10.1039/b904595n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rowley CN, Woo TK. Reaction Dynamics of β-Hydrogen Transfer in the Zirconocene Olefin Polymerization Catalyst: A DFT Path Sampling Study. Organometallics 2008. [DOI: 10.1021/om800891w] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher N. Rowley
- Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Tom K. Woo
- Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada
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Dynamics of ligand substitution in labile cobalt complexes resolved by ultrafast T-jump. Proc Natl Acad Sci U S A 2008; 105:12754-7. [PMID: 18725628 DOI: 10.1073/pnas.0806869105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ligand exchange of hydrated metal complexes is common in chemical and biological systems. Using the ultrafast T-jump, we examined this process, specifically the transformation of aqua cobalt (II) complexes to their fully halogenated species. The results reveal a stepwise mechanism with time scales varying from hundreds of picoseconds to nanoseconds. The dynamics are significantly faster when the structure is retained but becomes rate-limited when the octahedral-to-tetrahedral structural change bottlenecks the transformation. Evidence is presented, from bimolecular kinetics and energetics (enthalpic and entropic), for a reaction in which the ligand assists the displacement of water molecules, with the retention of the entering ligand in the activated state. The reaction time scale deviates by one to two orders of magnitude from that of ionic diffusion, suggesting the involvement of a collisional barrier between the ion and the much larger complex.
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13
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Rowley CN, Woo TK. A Path Sampling Study of Ru-Hydride-Catalyzed H2 Hydrogenation of Ethylene. J Am Chem Soc 2008; 130:7218-9. [PMID: 18481857 DOI: 10.1021/ja802219a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Christopher N. Rowley
- Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, ON, K1N 6N5 Canada
| | - Tom K. Woo
- Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, ON, K1N 6N5 Canada
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Rowley CN, Woo TK. Generation of initial trajectories for transition path sampling of chemical reactions with ab initio molecular dynamics. J Chem Phys 2007; 126:024110. [PMID: 17228946 DOI: 10.1063/1.2424712] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transition path sampling is an innovative method for focusing a molecular dynamics simulation on a reactive event. Although transition path sampling methods can generate an ensemble of reactive trajectories, an initial reactive trajectory must be generated by some other means. In this paper, the authors have evaluated three methods for generating initial reactive trajectories for transition path sampling with ab initio molecular dynamics. The authors have tested each of these methods on a set of chemical reactions involving the breaking and making of covalent bonds: the 1,2-hydrogen elimination in the borane-ammonia adduct, a tautomerization, and the Claisen rearrangement. The first method is to initiate trajectories from the potential energy transition state, which was effective for all reactions in the test set. Assigning atomic velocities found using normal mode analysis greatly improved the success of this method. The second method uses a high temperature molecular dynamics simulation and then iteratively reduces the total energy of the simulation until a low temperature reactive trajectory is found. This was effective in generating a low temperature trajectory from an initial trajectory run at 3000 K of the tautomerization reaction, although it failed for the other two. The third uses an orbital based bias potential to find a reactive trajectory and uses this trajectory to initiate an unbiased trajectory. The authors found that a highest occupied molecular orbital-lowest unoccupied molecular orbital bias could be used to find a reactive trajectory for the Claisen rearrangement, although it failed for the other two reactions. These techniques will help make it practical to use transition path sampling to study chemical reaction mechanisms that involve bond breaking and forming.
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Affiliation(s)
- Christopher N Rowley
- Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Ontario, K1N 6N5, Canada
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15
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Dimelow RJ, Burton NA, Hillier IH. The dynamics of water exchange in gadolinium DOTA complexes studied by transition path sampling and potential of mean force methods. Phys Chem Chem Phys 2007; 9:1318-23. [PMID: 17347704 DOI: 10.1039/b617068d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of water exchange at the Gd centre of the two isomers of [Gd(iii)DOTA](-) (gadolinate(1-), [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetato(4-)-N1,N4,N7,N10,O1,O4,O7,O10]) has been explored using transition path sampling and potential of mean force methods to sample those regions of phase space inaccessible to standard molecular dynamics simulation. We find that there are definite differences in the details of the solvent rearrangement accompanying the exchange of the capping water molecule for the two isomers. We conclude that these solvent effects, rather than any differences in the binding energy of the capping water, are central in determining the exchange rate. We find that the potential of mean force studies yield absolute and relative rates of water exchange for the two isomers that are in good agreement with experiment.
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Affiliation(s)
- Richard J Dimelow
- School of Chemistry, University of Manchester, Oxford Road, Manchester, UK
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Dimelow RJ, Bryce RA, Masters AJ, Hillier IH, Burton NA. Exploring reaction pathways with transition path and umbrella sampling: Application to methyl maltoside. J Chem Phys 2006; 124:114113. [PMID: 16555880 DOI: 10.1063/1.2172604] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The transition path sampling (TPS) method is a powerful approach to study chemical reactions or transitional properties on complex potential energy landscapes. One of the main advantages of the method over potential of mean force methods is that reaction rates can be directly accessed without knowledge of the exact reaction coordinate. We have investigated the complementary nature of these two differing approaches, comparing transition path sampling with the weighted histogram analysis method to study a conformational change in a small model system. In this case study, the transition paths for a transition between two rotational conformers of a model disaccharide molecule, methyl beta-D-maltoside, were compared with a free energy surface constrained by the two commonly used glycosidic (phi,psi) torsional angles. The TPS method revealed a reaction channel that was not apparent from the potential of mean force method, and the suitability of phi and psi as reaction coordinates to describe the isomerization in vacuo was confirmed by examination of the transition path ensemble. Using both transition state theory and transition path sampling methods, the transition rate was estimated. We have estimated a characteristic time between transitions of approximately 160 ns for this rare isomerization event between the two conformations of the carbohydrate. We conclude that transition path sampling can extract subtle information about the dynamics not apparent from the potential of mean force method. However, in calculating the reaction rate, the transition path sampling method required 27.5 times the computational effort than was needed by the potential of mean force method.
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Affiliation(s)
- Richard J Dimelow
- School of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom
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Shanoski JE, Payne CK, Kling MF, Glascoe EA, Harris CB. Ultrafast Infrared Mechanistic Studies of the Interaction of 1-Hexyne with Group 6 Hexacarbonyl Complexes. Organometallics 2005. [DOI: 10.1021/om049101m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennifer E. Shanoski
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Christine K. Payne
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Matthias F. Kling
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Elizabeth A. Glascoe
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Charles B. Harris
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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