1
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Bratteby K, Shalgunov V, Battisti UM, Petersen IN, van den Broek SL, Ohlsson T, Gillings N, Erlandsson M, Herth MM. Insights into Elution of Anion Exchange Cartridges: Opening the Path toward Aliphatic 18F-Radiolabeling of Base-Sensitive Tracers. ACS Pharmacol Transl Sci 2021; 4:1556-1566. [PMID: 34661074 PMCID: PMC8506604 DOI: 10.1021/acsptsci.1c00133] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Indexed: 01/16/2023]
Abstract
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Aliphatic nucleophilic
substitution (SN2) with [18F]fluoride is the
most widely applied method to prepare 18F-labeled positron
emission tomography (PET) tracers. Strong
basic conditions commonly used during 18F-labeling procedures
inherently limit or prohibit labeling of base-sensitive scaffolds.
The high basicity stems from the tradition to trap [18F]fluoride
on anion exchange cartridges and elute it afterward with basic anions.
This sequence is used to facilitate the transfer of [18F]fluoride from an aqueous to an aprotic organic, polar reaction
medium, which is beneficial for SN2 reactions. Furthermore,
this sequence also removes cationic radioactive contaminations from
cyclotron-irradiated [18O]water from which [18F]fluoride is produced. In this study, we developed an efficient
elution procedure resulting in low basicity that permits SN2 18F-labeling of base-sensitive scaffolds. Extensive
screening of trapping and elution conditions (>1000 experiments)
and
studying their influence on the radiochemical yield (RCY) allowed
us to identify a suitable procedure for this. Using this procedure,
four PET tracers and three synthons could be radiolabeled in substantially
higher RCYs (up to 2.5-fold) compared to those of previously published
procedures, even from lower precursor amounts. Encouraged by these
results, we applied our low-basicity method to the radiolabeling of
highly base-sensitive tetrazines, which cannot be labeled using state-of-art
direct aliphatic 18F-labeling procedures. Labeling succeeded
in RCYs of up to 20%. We believe that our findings facilitate PET
tracer development by opening the path toward simple and direct SN2 18F fluorination of base-sensitive substrates.
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Affiliation(s)
- Klas Bratteby
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Umberto Maria Battisti
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Ida Nyman Petersen
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Sara Lopes van den Broek
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Tomas Ohlsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Nic Gillings
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Maria Erlandsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
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2
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Pliego JR. The role of intermolecular forces in ionic reactions: the solvent effect, ion-pairing, aggregates and structured environment. Org Biomol Chem 2021; 19:1900-1914. [PMID: 33554992 DOI: 10.1039/d0ob02413a] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The environment enclosing an ionic species has a critical effect on its reactivity. In a more general sense, medium effects are not limited to the solvent, but involve the counter ion effect (ion pairing), formation of larger aggregates and structured environment as provided by the host in the case of host-guest complexes. In this review, a general view of the medium effect on anion-molecule reactions is presented. Nucleophilic substitution reactions of aliphatic (SN2) and aromatic (SNAr) systems, as well as elimination reactions (E2), are the focus of the discussion. In particular, nucleophilic fluorination with KF, CsF and tetraalkylammonium fluoride was used as the main model, because of the importance of this kind of reaction and the recent advances in the study of these systems. The solvent effect, ion pairing, formation of aggregates and formation of complexes with crown ethers, cryptands and calixarenes are discussed. For a deeper insight into the medium effect, many results of reliable theoretical calculations in close agreement with experiments were chosen as examples.
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Affiliation(s)
- Josefredo R Pliego
- Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João del-Rei, MG, Brazil.
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3
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Micro-solvation and counter ion effects on ionic reactions: Activation of potassium fluoride with 18-crown-6 and tert-butanol in aprotic solvents. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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4
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Silva SL, Valle MS, Pliego JR. Nucleophilic Fluorination with KF Catalyzed by 18-Crown-6 and Bulky Diols: A Theoretical and Experimental Study. J Org Chem 2020; 85:15457-15465. [PMID: 33227195 DOI: 10.1021/acs.joc.0c02229] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The activation of potassium fluoride for nucleophilic fluorination of alkyl halides is an important challenge because of the high lattice energy of this salt and its low solubility in many polar aprotic solvents. Crown ethers have been used for increasing the solubilization of KF during several decades. Nevertheless, these macrocycles are not enough to produce a high reaction rate. In this work, theoretical methods were used for designing a synergic combination of bulky diols with crown ethers able to accelerate this kind of reaction. The calculations have predicted that the bulky diol 1,4-Bis(2-hydroxy-2-propyl)benzene, which has distant hydroxyl groups, is able to catalyze nucleophilic fluorination in combination with 18-crown-6 via two hydrogen bonds to the SN2 transition state. Experimental studies following the theoretical predictions have confirmed the catalytic effect and the estimated kinetic data point out that the bulky diol at 1 mol L-1 in combination with 18-crown-6 is able to produce an 18-fold increase in the reaction rate in relation to crown ether catalysis only. The reaction produces 46% yield of fluorination after 24 h at moderate temperature of 82 °C, with minimal formation of the side elimination product. Thus, this work presents an improved method for fluorination with KF salt.
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Affiliation(s)
- Samuel L Silva
- Departamento de Ciências Naturais, Universidade Federal de Säo Joäo del-Rei, Säo Joäo del-Rei, 36301-160 MG, Brazil
| | - Marcelo S Valle
- Departamento de Ciências Naturais, Universidade Federal de Säo Joäo del-Rei, Säo Joäo del-Rei, 36301-160 MG, Brazil
| | - Josefredo R Pliego
- Departamento de Ciências Naturais, Universidade Federal de Säo Joäo del-Rei, Säo Joäo del-Rei, 36301-160 MG, Brazil
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5
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Dalessandro EV, Pliego JR. Reactivity and stability of ion pairs, dimers and tetramers versus solvent polarity: SNAr fluorination of 2-bromobenzonitrile with tetramethylammonium fluoride. Theor Chem Acc 2020. [DOI: 10.1007/s00214-019-2530-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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How difficult are anion-molecule SNAr reactions of unactivated arenes in the gas phase, dimethyl sulfoxide, and methanol solvents? Struct Chem 2018. [DOI: 10.1007/s11224-018-1172-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Pliego JR. Potassium fluoride activation for the nucleophilic fluorination reaction using 18-crown-6, [2.2.2]-cryptand, pentaethylene glycol and comparison with the new hydro-crown scaffold: a theoretical analysis. Org Biomol Chem 2018; 16:3127-3137. [DOI: 10.1039/c8ob00418h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ion-pair binding in the hydro-crown ether leads to more effective catalytic cycle for nucleophilic fluorination.
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Affiliation(s)
- Josefredo R. Pliego
- Departamento de Ciências Naturais
- Universidade Federal de São João del-Rei
- São João del-Rei
- Brazil
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8
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Pfeifer L, Engle KM, Pidgeon GW, Sparkes HA, Thompson AL, Brown JM, Gouverneur V. Hydrogen-Bonded Homoleptic Fluoride–Diarylurea Complexes: Structure, Reactivity, and Coordinating Power. J Am Chem Soc 2016; 138:13314-13325. [DOI: 10.1021/jacs.6b07501] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Lukas Pfeifer
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Keary M. Engle
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - George W. Pidgeon
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Hazel A. Sparkes
- ISIS Facility,
STFC-Rutherford Appleton Laboratory, OX11
0QX Didcot, United Kingdom
| | - Amber L. Thompson
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - John M. Brown
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Véronique Gouverneur
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
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9
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Carvalho NF, Pliego JR. Theoretical Design and Calculation of a Crown Ether Phase-Transfer-Catalyst Scaffold for Nucleophilic Fluorination Merging Two Catalytic Concepts. J Org Chem 2016; 81:8455-63. [DOI: 10.1021/acs.joc.6b01624] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Nathália F. Carvalho
- Departamento de Ciências
Naturais, Universidade Federal de São João Del-Rei, São
João del-Rei 36301-160, MG, Brazil
| | - Josefredo R. Pliego
- Departamento de Ciências
Naturais, Universidade Federal de São João Del-Rei, São
João del-Rei 36301-160, MG, Brazil
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10
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11
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de Paul N. Nziko V, Scheiner S. Effects of Angular Deformation on the Energetics of the S N2 Reaction. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Steve Scheiner
- Department of Chemistry and Biochemistry; Utah State University; 84322-0300 Logan UT USA
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12
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Ahmadi AA, Fattahi A. Influence of a β-OH substituent on SN2 reactions of fluoroethane: Intramolecular hydrogen bonding catalysis or inhibition? A theoretical study. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2015.05.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Lee SS, Jadhav VH, Kim JY, Chun JH, Lee A, Kim SY, Lee S, Kim DW. Quantum chemical investigation of the origin of activation of SN2 type halogenation by oligo-ethylene glycol—ionic liquids. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.03.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Chung LW, Sameera WMC, Ramozzi R, Page AJ, Hatanaka M, Petrova GP, Harris TV, Li X, Ke Z, Liu F, Li HB, Ding L, Morokuma K. The ONIOM Method and Its Applications. Chem Rev 2015; 115:5678-796. [PMID: 25853797 DOI: 10.1021/cr5004419] [Citation(s) in RCA: 752] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lung Wa Chung
- †Department of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China
| | - W M C Sameera
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Romain Ramozzi
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Alister J Page
- §Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
| | - Miho Hatanaka
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Galina P Petrova
- ∥Faculty of Chemistry and Pharmacy, University of Sofia, Bulgaria Boulevard James Bourchier 1, 1164 Sofia, Bulgaria
| | - Travis V Harris
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan.,⊥Department of Chemistry, State University of New York at Oswego, Oswego, New York 13126, United States
| | - Xin Li
- #State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zhuofeng Ke
- ∇School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Fengyi Liu
- ○Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Hai-Bei Li
- ■School of Ocean, Shandong University, Weihai 264209, China
| | - Lina Ding
- ▲School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Keiji Morokuma
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
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15
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Liu Y, Chen C, Li H, Huang KW, Tan J, Weng Z. Efficient SN2 Fluorination of Primary and Secondary Alkyl Bromides by Copper(I) Fluoride Complexes. Organometallics 2013. [DOI: 10.1021/om4008967] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yanpin Liu
- Department
of Chemistry, Fuzhou University, Fujian 350108, China
| | - Chaohuang Chen
- Department
of Chemistry, Fuzhou University, Fujian 350108, China
| | - Huaifeng Li
- Division
of Physical Sciences and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Kuo-Wei Huang
- Division
of Physical Sciences and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Jianwei Tan
- Department
of Chemistry, Fuzhou University, Fujian 350108, China
| | - Zhiqiang Weng
- Department
of Chemistry, Fuzhou University, Fujian 350108, China
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16
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New insights on reaction pathway selectivity promoted by crown ether phase-transfer catalysis: Model ab initio calculations of nucleophilic fluorination. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcata.2012.07.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Sunoj RB, Anand M. Microsolvated transition state models for improved insight into chemical properties and reaction mechanisms. Phys Chem Chem Phys 2012; 14:12715-36. [PMID: 22893252 DOI: 10.1039/c2cp41719g] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over the years, several methods have been developed to effectively represent the chemical behavior of solutes in solvents. The environmental effects arising due to solvation can generally be achieved either through inclusion of discrete solvent molecules or by inscribing into a cavity in a homogeneous and continuum dielectric medium. In both these approaches of computational origin, the perturbations on the solute induced by the surrounding solvent are at the focus of the problem. While the rigor and method of inclusion of solvent effects vary, such solvation models have found widespread applications, as evident from modern chemical literature. A hybrid method, commonly referred to as cluster-continuum model (CCM), brings together the key advantages of discrete and continuum models. In this perspective, we intend to highlight the latent potential of CCM toward obtaining accurate estimates on a number of properties as well as reactions of contemporary significance. The objective has generally been achieved by choosing illustrative examples from the literature, besides expending efforts to bring out the complementary advantages of CCM as compared to continuum or discrete solvation models. The majority of examples emanate from the prevalent applications of CCM to organic reactions, although a handful of interesting organometallic reactions have also been discussed. In addition, increasingly accurate computations of properties like pK(a) and solvation of ions obtained using the CCM protocol are also presented.
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Affiliation(s)
- Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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18
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Kim JY, Kim DW, Song CE, Chi DY, Lee S. Nucleophilic substitution reactions promoted by oligoethylene glycols: a mechanistic study of ion-pair SN
2 processes facilitated by Lewis base. J PHYS ORG CHEM 2012. [DOI: 10.1002/poc.3010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ju-Young Kim
- Department of Applied Chemistry; Kyung Hee University; Gyeonggi 446-701 Korea
| | - Dong Wook Kim
- Department of Nuclear Medicine Cyclotron Research Center, Research Institute of Clinical Medicine; Chonbuk National University Medical School; Jeonju Jeonbuk 561-712 Korea
| | - Choong Eui Song
- Department of Chemistry and Department of Energy Science; Sungkyunkwan University; 300 Cheoncheon, Jangan-gu Suwon Gyeonggi 440-746 Korea
| | - Dae Yoon Chi
- Department of Chemistry; Sogang University; 1 Shinsudong Mapogu Seoul 121-742 Korea
| | - Sungyul Lee
- Department of Applied Chemistry; Kyung Hee University; Gyeonggi 446-701 Korea
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19
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Cheong PHY, Legault CY, Um JM, Çelebi-Ölçüm N, Houk KN. Quantum mechanical investigations of organocatalysis: mechanisms, reactivities, and selectivities. Chem Rev 2011; 111:5042-137. [PMID: 21707120 PMCID: PMC3154597 DOI: 10.1021/cr100212h] [Citation(s) in RCA: 429] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paul Ha-Yeon Cheong
- Oregon State University, Department of Chemistry, 153 Gilbert Hall, Corvallis, OR 97331-4003 USA
| | - Claude Y. Legault
- University of Sherbrooke, Department of Chemistry, 2500 boul. de l’Université, local D1-3029, Sherbrooke (Québec) J1K 2R1 CANADA
| | - Joann M. Um
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
| | - Nihan Çelebi-Ölçüm
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
| | - K. N. Houk
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
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20
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Hollingworth C, Hazari A, Hopkinson MN, Tredwell M, Benedetto E, Huiban M, Gee AD, Brown JM, Gouverneur V. Palladium-catalyzed allylic fluorination. Angew Chem Int Ed Engl 2011; 50:2613-7. [PMID: 21370349 DOI: 10.1002/anie.201007307] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Indexed: 11/12/2022]
Affiliation(s)
- Charlotte Hollingworth
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
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21
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Hollingworth C, Hazari A, Hopkinson MN, Tredwell M, Benedetto E, Huiban M, Gee AD, Brown JM, Gouverneur V. Palladium-Catalyzed Allylic Fluorination. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201007307] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Pliego Jr. JR. Chemical reactions inside structured nano-environment: SN2vs. E2 reactions for the F−+ CH3CH2Cl system. Phys Chem Chem Phys 2011; 13:779-82. [DOI: 10.1039/c0cp01182g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Mann DJ. Aziridinium Ion Ring Formation from Nitrogen Mustards: Mechanistic Insights from Ab Initio Dynamics. J Phys Chem A 2010; 114:4486-93. [DOI: 10.1021/jp9079553] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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25
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Im S, Jang SW, Kim HR, Oh YH, Park SW, Lee S, Chi DY. A Mechanistic Study of SN2 Reaction in a Diol Solvent. J Phys Chem A 2009; 113:3685-9. [DOI: 10.1021/jp900576x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Suk Im
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Sung-Woo Jang
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Hye-Rim Kim
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Young-Ho Oh
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Sung-Woo Park
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Sungyul Lee
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
| | - Dae Yoon Chi
- Department of Chemistry, Sogang University, Seoul 121-742, S. Korea
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26
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Pliego JR. First solvation shell effects on ionic chemical reactions: new insights for supramolecular catalysis. J Phys Chem B 2009; 113:505-10. [PMID: 19099433 DOI: 10.1021/jp808581t] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This article presents a detailed discussion on medium effect on ionic S(N)2 reactions. Ion pairing and the first solvation shell play the main role on reactivity. Ab initio calculations are used to show that a combination of apolar molecular cavity with polar hydroxyl groups can have catalytic effects on these reactions. The present results open an avenue of development for supramolecular catalysts able to control bimolecular ionic reactions. In particular, this new catalytic concept could be useful in nucleophilic fluorinations.
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Affiliation(s)
- Josefredo R Pliego
- Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, 09972-270 Diadema, SP, Brazil.
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27
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An electron localization function and catastrophe theory analysis on the molecular mechanism of gas-phase identity SN2 reactions. Theor Chem Acc 2008. [DOI: 10.1007/s00214-008-0427-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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28
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Pliego, Jr JR, Piló-Veloso D. Effects of ion-pairing and hydration on the SNAr reaction of the F−with p-chlorobenzonitrile in aprotic solvents. Phys Chem Chem Phys 2008; 10:1118-24. [DOI: 10.1039/b716159j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Lee SS, Kim HS, Hwang TK, Oh YH, Park SW, Lee S, Lee BS, Chi DY. Efficiency of bulky protic solvent for SN2 reaction. Org Lett 2007; 10:61-4. [PMID: 18052384 DOI: 10.1021/ol702627m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We calculate and compare the effects of aprotic vs protic solvent on the rate of SN2 reaction [F- + C3H7OMs--> C3H7F + OMs-]. We find that aprotic solvent acetonitrile is more efficient than a small protic solvent such as methanol. Bulky protic solvent (tert-butyl alcohol) is predicted to be quite efficient, giving the rate constant that is similar to that in CH3CN. Our calculated relative activation barriers of the SN2 reaction in methanol, tert-butyl alcohol, and CH3CN are in good agreement with experimental observations.
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Affiliation(s)
- Sung-Sik Lee
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 446-701, S. Korea
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Westphal E, Pliego JR. Ab Initio, Density Functional Theory, and Continuum Solvation Model Prediction of the Product Ratio in the SN2 Reaction of NO2- with CH3CH2Cl and CH3CH2Br in DMSO Solution. J Phys Chem A 2007; 111:10068-74. [PMID: 17880192 DOI: 10.1021/jp074842x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The reaction pathways for the interaction of the nitrite ion with ethyl chloride and ethyl bromide in DMSO solution were investigated at the ab initio level of theory, and the solvent effect was included through the polarizable continuum model. The performance of BLYP, GLYP, XLYP, OLYP, PBE0, B3PW91, B3LYP, and X3LYP density functionals has been tested. For the ethyl bromide case, our best ab initio calculations at the CCSD(T)/aug-cc-pVTZ level predicts product ratio of 73% and 27% for nitroethane and ethyl nitrite, respectively, which can be compared with the experimental values of 67% and 33%. This translates to an error in the relative DeltaG* of only 0.17 kcal mol(-1). No functional is accurate (deviation <0.5 kcal mol(-1)) for predicting relative DeltaG*. The hybrid X3LYP functional presents the best performance with deviation 0.82 kcal mol(-1). The present problem should be included in the test set used for the evaluation of new functionals.
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Affiliation(s)
- Eduard Westphal
- Departamento de Química, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, SC, Brazil
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31
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Oh YH, Ahn DS, Chung SY, Jeon JH, Park SW, Oh SJ, Kim DW, Kil HS, Chi DY, Lee S. Facile SN2 Reaction in Protic Solvent: Quantum Chemical Analysis. J Phys Chem A 2007; 111:10152-61. [PMID: 17880052 DOI: 10.1021/jp0743929] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We study the effects of protic solvent (water, methanol, ethanol, and tert-butyl alcohol) and cation (Na+, K+, Cs+) on the unsymmetrical SN2 reaction X- + RY --> RX + Y- (X = F, Br; R = CH3,C3H7;Y = Cl, OMs). We describe a series of calculations for the S(N)2 reaction mechanism under the influence of cation and protic solvent, presenting the structures of pre- and postreaction complexes and transition states and the magnitude of the activation barrier. An interesting mechanism is proposed, in which the protic solvent molecules that are shielded from the nucleophile by the intervening cation act as a Lewis base to reduce the unfavorable Coulombic influence of the cation on the nucleophile. We predict that the reaction barrier for the S(N)2 reaction is significantly lowered by the cooperative effects of cation and protic solvent. We show that the cation and protic solvent, each of which has been considered to retard the SN2 reactivity of the nucleophile, can accelerate the reaction tremendously when they interact with the fluoride ion in an intricate, combined fashion. This alternative S(N)2 mechanism is discussed in relation to the recently observed phenomenal efficiency of fluorination in tert-alcohol media [Kim, D. W.; et al. J. Am. Chem. Soc. 2006, 128, 16394].
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Affiliation(s)
- Young-Ho Oh
- College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 449-701, Korea
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