1
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Nakamura T, Okuno K, Nishiyori R, Shirakawa S. Hydrogen‐Bonding Catalysis of Alkyl‐Onium Salts. Chem Asian J 2020; 15:463-472. [DOI: 10.1002/asia.201901652] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Takumi Nakamura
- Department of Environmental ScienceGraduate School of Fisheries and Environmental SciencesNagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
| | - Ken Okuno
- Department of Environmental ScienceGraduate School of Fisheries and Environmental SciencesNagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
| | - Ryuichi Nishiyori
- Department of Environmental ScienceGraduate School of Fisheries and Environmental SciencesNagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
| | - Seiji Shirakawa
- Department of Environmental ScienceGraduate School of Fisheries and Environmental SciencesNagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
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2
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Kaneko S, Kumatabara Y, Shimizu S, Maruoka K, Shirakawa S. Hydrogen-bonding catalysis of sulfonium salts. Chem Commun (Camb) 2017; 53:119-122. [PMID: 27892549 DOI: 10.1039/c6cc08411g] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although quaternary ammonium and phosphonium salts are known as important catalysts in phase-transfer catalysis, the catalytic ability of tertiary sulfonium salts has not yet been well demonstrated. Herein, we demonstrate the catalytic ability of trialkylsulfonium salts as hydrogen-bonding catalysts on the basis of the characteristic properties of the acidic α hydrogen atoms on alkylsulfonium salts.
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Affiliation(s)
- Shiho Kaneko
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Yusuke Kumatabara
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Shoichi Shimizu
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Izumi-cho, Narashino, Chiba 275-8575, Japan
| | - Keiji Maruoka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Seiji Shirakawa
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521, Japan.
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3
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Liu S, Maruoka K, Shirakawa S. Chiral Tertiary Sulfonium Salts as Effective Catalysts for Asymmetric Base-Free Neutral Phase-Transfer Reactions. Angew Chem Int Ed Engl 2017; 56:4819-4823. [PMID: 28371093 DOI: 10.1002/anie.201612328] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/07/2017] [Indexed: 01/08/2023]
Abstract
Although chiral quaternary ammonium and phosphonium salts are commonly used for asymmetric organocatalysis, the catalytic ability of chiral tertiary sulfonium salts has yet to be demonstrated in asymmetric synthesis. Herein, we show that chiral bifunctional trialkylsulfonium salts catalyze highly enantioselective conjugate additions of 3-substituted oxindoles to maleimides under base-free neutral phase-transfer conditions.
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Affiliation(s)
- Shiyao Liu
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Keiji Maruoka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Seiji Shirakawa
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
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4
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Liu S, Maruoka K, Shirakawa S. Chiral Tertiary Sulfonium Salts as Effective Catalysts for Asymmetric Base-Free Neutral Phase-Transfer Reactions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612328] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Shiyao Liu
- Department of Environmental Science; Graduate School of Fisheries and Environmental Sciences; Nagasaki University; 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
| | - Keiji Maruoka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo Kyoto 606-8502 Japan
| | - Seiji Shirakawa
- Department of Environmental Science; Graduate School of Fisheries and Environmental Sciences; Nagasaki University; 1-14 Bunkyo-machi Nagasaki 852-8521 Japan
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5
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Lukinavičius G, Tomkuvienė M, Masevičius V, Klimašauskas S. Enhanced chemical stability of adomet analogues for improved methyltransferase-directed labeling of DNA. ACS Chem Biol 2013; 8:1134-9. [PMID: 23557731 DOI: 10.1021/cb300669x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Methyltransferases catalyze specific transfers of methyl groups from the ubiquitous cofactor S-adenosyl-l-methionine (AdoMet) to various nucleophilic positions in biopolymers like DNA, RNA, and proteins. We had previously described synthesis and application of AdoMet analogues carrying sulfonium-bound 4-substituted but-2-ynyl side chains for transfer by methyltransferases. Although useful in certain applications, these cofactor analogues exhibited short lifetimes in physiological buffers. Examination of the reaction kinetics and products showed that their fast inactivation followed a different pathway than observed for AdoMet and rather involved a pH-dependent addition of a water molecule to the side chain. This side reaction was eradicated by synthesis of a series of cofactor analogues in which the separation between an electronegative group and the triple bond was increased from one to three carbon units. The designed hex-2-ynyl moiety-based cofactor analogues with terminal amino, azide, or alkyne groups showed a markedly improved enzymatic transalkylation activity and proved well suitable for methyltransferase-directed sequence-specific labeling of DNA in vitro and in bacterial cell lysates.
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Affiliation(s)
| | - Miglė Tomkuvienė
- Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
| | - Viktoras Masevičius
- Institute of Biotechnology, Vilnius University, LT-02241 Vilnius, Lithuania
- Faculty of Chemistry, Vilnius University, LT-03225 Vilnius, Lithuania
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6
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Zarrin H, Wu J, Fowler M, Chen Z. High durable PEK-based anion exchange membrane for elevated temperature alkaline fuel cells. J Memb Sci 2012. [DOI: 10.1016/j.memsci.2011.12.041] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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7
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Haiss P, Zeller KP. Concerning the deprotonation of the trimethylsulfonium ion by the dimethylsulfinyl anion. Org Biomol Chem 2011; 9:7748-54. [DOI: 10.1039/c1ob05889d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Peter Haiss
- Institut für Organische Chemie, Tübingen, Germany
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8
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Appel R, Hartmann N, Mayr H. Scope and Limitations of Cyclopropanations with Sulfur Ylides. J Am Chem Soc 2010; 132:17894-900. [DOI: 10.1021/ja1084749] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roland Appel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Nicolai Hartmann
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
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9
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Appel R, Mayr H. Nucleophilic Reactivities of Sulfur Ylides and Related Carbanions: Comparison with Structurally Related Organophosphorus Compounds. Chemistry 2010; 16:8610-4. [DOI: 10.1002/chem.201001455] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Qi C, Du Y, Lu Y, Sun X, Zhang XM. Equilibrium Acidities and Homolytic Bond Dissociation Enthalpies of the Acidic C−H Bonds in Phosphonates and Related Phosphorus Containing Compounds. J Org Chem 2009; 74:8078-85. [DOI: 10.1021/jo901270p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chenze Qi
- Institute of Applied Chemistry and Department of Chemistry, Shaoxing University, Zhejiang 312000, People’s Republic of China
| | - Yijun Du
- Institute of Applied Chemistry and Department of Chemistry, Shaoxing University, Zhejiang 312000, People’s Republic of China
| | - Yueqing Lu
- Institute of Applied Chemistry and Department of Chemistry, Shaoxing University, Zhejiang 312000, People’s Republic of China
| | - Xudong Sun
- Institute of Applied Chemistry and Department of Chemistry, Shaoxing University, Zhejiang 312000, People’s Republic of China
| | - Xian-Man Zhang
- Institute of Applied Chemistry and Department of Chemistry, Shaoxing University, Zhejiang 312000, People’s Republic of China
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11
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Li X, Deng H, Zhu XQ, Wang X, Liang H, Cheng JP. Establishment of the C-NO bond dissociation energy scale in solution and its application in analyzing the trend of NO transfer from C-nitroso compound to thiols. J Org Chem 2009; 74:4472-8. [PMID: 19453157 DOI: 10.1021/jo900732b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first set of experimentally determined C-NO bond homolytic and heterolytic dissociation enthalpies in solution is derived by using direct titration calorimetry combined with appropriate electrode potentials through thermodynamic cycles. The homolytic bond dissociation energy scale (BDEs) of the corresponding C-NO bonds in the gas phase was also calculated at the MP2/6-311+G**//B3LYP/6-31G* level and BP86/6-31G*//B3LYP/6-31G* level of theory for the purpose of comparison. The C-NO and S-NO bond thermodynamic parameters were used to predict the trend of NO transfer from C-nitroso substrates to thiols in acetonitrile solution.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Elemento-Organic Chemistry, Department of Chemistry, Nankai University, Tianjin 300071, China
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12
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Forbes DC, Bettigeri SV, Pischek SC. Highly stereoselective methylene transfers onto butanediacetal-protected chiral non-racemic sulfinyl imines using S-ylide technology. Chem Commun (Camb) 2009:1882-4. [PMID: 19319433 DOI: 10.1039/b822779a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diastereomeric ratios of >95 : 5 were obtained when performing methylene transfers onto imines originating from d-mannitol and (S)-(-)-2-methyl-2-propane sulfinamide or ascorbic acid and (R)-(-)-2-methyl-2-propane sulfinamide.
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Affiliation(s)
- David C Forbes
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA.
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13
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Forbes DC, Bettigeri SV, Patrawala SA, Pischek SC, Standen MC. S-Methylidene Agents: Preparation of Chiral Non-Racemic Heterocycles. Tetrahedron 2009; 65:70-76. [PMID: 20049065 PMCID: PMC2657720 DOI: 10.1016/j.tet.2008.10.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Reaction of sulfur ylide with aldehyde, imine, and ketone functionality affords the desired three-membered heterocycle in excellent yield. The sulfur ylide is generated in situ upon decarboxylation of carboxymethylsulfonium betaine functionality. Of the seven carboxymethylsulfonium betaine derivatives surveyed, the highest level of conversion of π-acceptor to heterocycle was obtained having S-methyl and S-phenyl functionality bound to a thioacetate derivative. Methylene aziridinations and epoxidations involving the decarboxylation of carboxymethylsulfonium betaine functionality complements existing technologies with the advantages of the reaction protocol, levels of conversion and scope. While moderate levels of diastereocontrol were observed in the aziridination of imine functionality, the four oxiranes resolved using Jacobsen's Co(II)-salen complex were obtained in both high yield and enantioselectivity. The isolated chiral non-racemic oxiranes constitute the formal synthesis of chelonin-B and combretastatin starting from 3-bromo-4-methoxybenzaldehyde and 3,4,5-trimethoxybenzaldehyde respectively.
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Affiliation(s)
- David C. Forbes
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | | | - Samit A. Patrawala
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | - Susanna C. Pischek
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
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Forbes DC, Bettigeri SV, Amin SR, Bean CJ, Law AM, Stockman RA. Synthesis of Chiral Aziridines through Decarboxylative Generation of Sulfur Ylides and their Reaction with Chiral Sulfinyl Imines. SYNTHETIC COMMUN 2009; 39:2405-2422. [PMID: 20664808 PMCID: PMC2906816 DOI: 10.1080/00397910802654898] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Reaction of sulfur ylide with a series of aryl substituted chiral non-racemic sulfinyl imines afforded the corresponding aziridines in high yield and good stereoselection. The sulfur ylides were generated by the thermally induced decarboxylation of carboxymethylsulfonium betaines. A drop in the diastereomeric ratio was observed when going from electron deficient to electron releasing aryl substituted imines. Sulfonium methylidene aziridinations involving the decarboxylation of carboxymethylsulfonium betaine functionality compliments existing technologies with the advantages of the reaction protocol, levels of conversion and scope.
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Affiliation(s)
- David C. Forbes
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | | | - Sejal R. Amin
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | - Christie J. Bean
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | - Amanda M. Law
- Department of Chemistry, University of South Alabama, Mobile, AL 36688, USA
| | - Robert A. Stockman
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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15
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Fu Y, Wang HJ, Chong SS, Guo QX, Liu L. An Extensive Ylide Thermodynamic Stability Scale Predicted by First-Principle Calculations. J Org Chem 2008; 74:810-9. [DOI: 10.1021/jo802128w] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yao Fu
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Hua-Jing Wang
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Sha-Sha Chong
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qing-Xiang Guo
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Department of Chemistry, Tsinghua University, Beijing 100084, China
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16
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Forbes DC, Amin SR, Bean CJ, Standen MC. Aryl-Substituted Sulfonium Betaines: Preparation and Use in the Epoxidation of Aldehydes. J Org Chem 2006; 71:8287-90. [PMID: 17025328 DOI: 10.1021/jo061370u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermally induced decarboxylation of carboxymethylsulfonium betaines results in formation of the corresponding sulfur ylides in situ. Decarboxylation rates for a range of arylcarboxymethylsulfonium betaine salts have been determined using NMR spectroscopy, and the efficiency of ylide generation and trapping has been evaluated via methylidene transfer to a range of aldehydes to form epoxides.
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Affiliation(s)
- David C Forbes
- Department of Chemistry, University of South Alabama, Mobile, Alabama 36688, USA.
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17
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Song KS, Liu L, Guo QX. Effects of alpha-ammonium, alpha-phosphonium, and alpha-sulfonium groups on C-H bond dissociation energies. J Org Chem 2003; 68:4604-7. [PMID: 12762784 DOI: 10.1021/jo020709j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
C-H bond dissociation energies of alpha-ammonium-, alpha-phosphonium-, or alpha-sulfonium-substituted methanes and toluenes were calculated to a precision of 1-2 kcal/mol. It was found that alpha-ammonium, alpha-phosphonium, and alpha-sulfonium groups all destabilize a methyl radical. alpha-Ammonium also destabilizes a benzyl radical, whereas alpha-phosphonium and alpha-sulfonium either slightly stabilize or destabilize a benzyl radical depending on their alkylation state.
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Affiliation(s)
- Ke-Sheng Song
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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18
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Luo YR. Bond dissociation energies and the Hammett correlation, Part 1: Remotely substituted aromatic compounds and vitamin E. INT J CHEM KINET 2002. [DOI: 10.1002/kin.10075] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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N-NO bond dissociation energies of N-nitroso diphenylamine derivatives (or analogues) and their radical anions: implications for the effect of reductive electron transfer on N-NO bond activation and for the mechanisms of NO transfer to nitranions. J Org Chem 2000; 65:6729-35. [PMID: 11052125 DOI: 10.1021/jo000865v] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The heterolytic and homolytic N-NO bond dissociation energies [i.e., deltaHhet(N-NO) and deltaHhomo(N-NO)] of 12 N-nitroso-diphenylamine derivatives (1-12) and two N-nitrosoindoles (13 and 14) in acetonitrile were determined by titration calorimetry and from a thermodynamic cycle, respectively. Comparison of these two sets of data indicates that homolysis of the N-NO bonds to generate NO* and nitrogen radical is energetically much more favorable (by 23.3-44.8 kcal/mol) than the corresponding heterolysis to generate a pair of ions, giving hints for the driving force and possible mechanism of NO-initiated chemical and biological transformations. The first (N-NO)-* bond dissociation energies [i.e., deltaH(N-NO)-* and deltaH'(N-NO)-*] of radical anions 1-*-14-* were also derived on the basis of appropriate cycles utilizing the experimentally measured deltaHhet(N-NO) and electrochemical data. Comparisons of these two quantities with those of the neutral N-NO bonds indicate a remarkable bond activation upon a possible one-electron transfer to the N-NO bonds, with an average bond-weakening effect of 48.8 +/- 0.3 kcal/mol for heterolysis and 22.3 +/- 0.3 kcal/mol for homolysis, respectively. The good to excellent linear correlations among the energetics of the related heterolytic processes [deltaHhet(N-NO), deltaH(N-NO)-*, and pKa(N-H)] and the related homolytic processes [deltaHhomo(N-NO), deltaH'(N-NO)-*, and BDE(N-H)] imply that the governing structural factors for these bond scissions are similar. Examples illustrating the use of such bond energetic data jointly with relevant redox potentials for analyzing various mechanistic possibilities for nitrosation of nitranions are presented.
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20
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Cheng JP, Liu B, Zhao Y, Wen Z, Sun Y. Homolytic Cleavage Energies of R−H Bonds Centered on Carbon Atoms of High Electronegativity: First General Observations of O-type Variation on C−H BDEs and the Implication for the Governing Factors Leading to the Distinct O/S Patterns of Radical Substituent Effects. J Am Chem Soc 2000. [DOI: 10.1021/ja994120m] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jin-Pei Cheng
- Contribution from the Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Bo Liu
- Contribution from the Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yongyu Zhao
- Contribution from the Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhong Wen
- Contribution from the Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yongkai Sun
- Contribution from the Department of Chemistry, Nankai University, Tianjin 300071, China
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21
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The first O-NO bond energy scale in solution: heterolytic and homolytic cleavage enthalpies of O-nitrosyl carboxylate compounds. Org Lett 2000; 2:265-8. [PMID: 10814298 DOI: 10.1021/ol990340t] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The first series of O-NO bond dissociation enthalpies was determined in solution for eight O-nitrosyl carboxylate compounds by direct titration calorimetry with a thermodynamic cycle. The derived bond energy data may serve as a quantitative guide to predict the NO binding and releasing abilities of the related amino acids.
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22
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Fountain KR, Tad-Y DB, Paul TW, Golynskiy MV. The alpha-Effect in Benzyl Transfers from Benzylphenylmethyl Sulfonium Salts to N-Methylbenzohydroxamate Anions. J Org Chem 1999; 64:6547-6553. [PMID: 11674656 DOI: 10.1021/jo981902+] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The investigation of the occurrence of the alpha-effect in group transfers from phenyldialkyl sulfonium ions where one alkyl group is benzyl allows an assay of the effect of changing the nature of the C atom being transferred. The size of the alpha-effect responds to increasing electron demand, as methyl transfers do. Quantitative relationships between the size of the alpha-effect are established from both the nucleophilic side and the leaving group side of the S(N)2 transition state.
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23
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Cheng JP, Liu B, Zhao Y, Sun Y, Zhang XM, Lu Y. Effects of Adjacent Onium Cations and Remote Substituents on the H−A+ Bond Equilibrium Acidities in Dimethyl Sulfoxide Solution. An Extensive Ylide Thermodynamic Stability Scale and Implication for the Importance of Resonance Effect on Ylide Stabilities. J Org Chem 1999. [DOI: 10.1021/jo981954z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jin-Pei Cheng
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Bo Liu
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yongyu Zhao
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yongkai Sun
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Xian-Man Zhang
- Department of Chemistry, Nankai University, Tianjin 300071, China
| | - Yun Lu
- Department of Chemistry, Nankai University, Tianjin 300071, China
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