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Eisenstein O. From the Felkin‐Anh Rule to the Grignard Reaction: an Almost Circular 50 Year Adventure in the World of Molecular Structures and Reaction Mechanisms with Computational Chemistry**. Isr J Chem 2022. [DOI: 10.1002/ijch.202100138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Odile Eisenstein
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, 34095 France Department of Chemistry and Hylleraas Centre for Quantum Molecular Sciences University of Oslo Oslo 0315 Norway
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2
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de Rezende FMP, Freitas MP, Ramalho TC. Probing long-range spin-spin coupling constants in 2-halo-substituted cyclohexanones and cyclohexanethiones: The role of solvent and stereoelectronic effects. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:810-816. [PMID: 29667226 DOI: 10.1002/mrc.4739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 06/08/2023]
Abstract
Earlier studies with 2-bromocyclohexanone demonstrated a measurable long-range coupling constant (4 JH2,H6 ) for the equatorial conformer, although 4 JH2,H4 and 4 JH4,H6 were not observed; as a consequence, it is inferred that the carbonyl group plays an important role particularly due to hyperconjugative interactions σC2H2 →π*C═O and σC6H6 →π*C═O. In the present study, NBO analysis and coupling constant calculations were performed to cyclohexanone and cyclohexanethione alpha substituted with F, Cl, and Br, aiming to evaluate the halogen effect and acceptor character of the π* orbital on the long-range coupling pathway. The σC2H2 →π*C1═Y and σC6H6 →π*C1═Y (Y═O and S) hyperconjugative interactions for the equatorial conformer indeed contribute for the 4 JH2,H6 transmission mechanism. Surprisingly, the 4 JH2,H6 value is higher for the carbonyl compounds, although the interactions σC2H2 →π*C═Y and σC6H6 →π*C═Y are more efficient for the thiocarbonyl compounds. Accordingly, the Fermi contact (FC) contribution for the thiocarbonyl compounds decays deeper than in ketones, thus reducing more the 4 JH2,H6 values. Moreover, both πC═S →σ*C─X and πC═S →σ*C─H interactions seem to be stronger in thiocarbonyl than in carbonylic compounds. The implicit solvent effect (DMSO and water) on the coupling constant values was negligible when compared with the gas phase. On the other hand, an explicit solvent effect was found and 4 JH2,H6 for the thiocarbonyl compounds appeared to be more sensitive than for the cyclohexanones.
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Affiliation(s)
- Fátima M P de Rezende
- Department of Chemistry, Federal University of Lavras, Lavras, 37200-000, MG, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, Lavras, 37200-000, MG, Brazil
| | - Teodorico C Ramalho
- Department of Chemistry, Federal University of Lavras, Lavras, 37200-000, MG, Brazil
- Center for Basic and Applied Research, Faculty of Informatics and Management, University of Hradec Kralove, Rokitanskeho 62, Hradec Kralove, 50003, Czech Republic
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3
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de Melo UZ, Silva RGM, Yamazaki DAS, Pontes RM, Gauze GF, Rosa FA, Rittner R, Basso EA. NMR spectroscopy and theoretical calculations in the conformational analysis of 1-methylpyrrolidin-2-one 3-halo-derivatives. J Phys Chem A 2015; 119:2111-21. [PMID: 25679501 DOI: 10.1021/jp512378g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study reports the results of ab initio and density functional theory (DFT) electronic structure calculations as well as (3)J(HH) experimental and calculated coupling constant data obtained in the investigation of the conformational equilibrium of 3-halo-derivatives of 1-methylpyrrolidin-2-one. The five-membered ring assumes an envelope conformation owing to the plane of formation of the O═C-N-R bond, with C4 forming the "envelope lid". When the conformation changes, the "lid" alternates between positions above and below the amide plane. The α-carbonyl halogen assumes two positions: a pseudo-axial and a pseudo-equatorial. In the gaseous phase, the calculations indicate that the pseudo-axial conformer is more stable and preferable going down the halogen family. Natural bond orbital analysis showed that electronic delocalization is significant only for the iodo derivative. In the other derivatives, the electrostatic repulsion between oxygen and the halogen determines the conformational equilibrium. When the solvated molecule was taken into account, the pseudo-equatorial conformer population increased with the relative permittivity of the solvent. This variation was strong in the fluoro derivative, and the preference was inverted. In the chlorine derivative, the two populations became closer in methanol and acetonitrile. In the bromine and iodine derivatives, the percentage of pseudo-equatorial conformer increased only slightly owing to the dipole moment of the conformation: the pseudo-equatorial conformation has a greater dipole moment and thus is stable in media with high relative permittivity.
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Affiliation(s)
- Ulisses Zonta de Melo
- Chemistry Department, State University of Maringa , Avenida Colombo, 5790, 87020-900, Maringa, Paraná, Brazil
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4
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Engel-Andreasen J, Wich K, Laursen JS, Harris P, Olsen CA. Effects of Thionation and Fluorination on Cis–Trans Isomerization in Tertiary Amides: An Investigation of N-Alkylglycine (Peptoid) Rotamers. J Org Chem 2015; 80:5415-27. [DOI: 10.1021/acs.joc.5b00048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jens Engel-Andreasen
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
| | - Kathrine Wich
- Center for Biopharmaceuticals and Department of Drug Design & Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jonas S. Laursen
- Center for Biopharmaceuticals and Department of Drug Design & Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Pernille Harris
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
| | - Christian A. Olsen
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
- Center for Biopharmaceuticals and Department of Drug Design & Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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Whangbo MH, Wolfe S. The Orbital Interaction Approach to Structural and Conformational Problems in Organic Chemistry. Isr J Chem 2013. [DOI: 10.1002/ijch.198000050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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Olivato PR, Santos JMM, Contieri B, Cerqueira CR, Rodrigues DNS, Vinhato E, Zukerman-Schpector J, Colle MD. Spectroscopic and theoretical studies of some 3-(4'-substituted phenylsulfanyl)-1-methyl-2-piperidones. Molecules 2013; 18:7492-509. [PMID: 23807576 PMCID: PMC6269881 DOI: 10.3390/molecules18077492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 06/20/2013] [Accepted: 06/21/2013] [Indexed: 11/16/2022] Open
Abstract
The analysis of the IR carbonyl bands of some 3-(4′-substituted phenylsulfanyl)-1-methyl-2-piperidones 1–6 bearing substituents: NO2 (compound 1), Br (compound 2), Cl (compound 3), H (compound 4) Me (compound 5) and OMe (compound 6) supported by B3LYP/6-31+G(d,p) and PCM calculations along with NBO analysis (for compound 4) and X-ray diffraction (for 2) indicated the existence of two stable conformations, i.e., axial (ax) and equatorial (eq), the former corresponding to the most stable and the least polar one in the gas phase calculations. The sum of the energy contributions of the orbital interactions (NBO analysis) and the electrostatic interactions correlate well with the populations and the νCO frequencies of the ax and eq conformers found in the gas phase. Unusually, in solution of the non-polar solvents n-C6H14 and CCl4, the more intense higher IR carbonyl frequency can be ascribed to the ax conformer, while the less intense lower IR doublet component to the eq one. The same νCO frequency trend also holds in polar solvents, that is νCO (eq) < νCO (ax). However, a reversal of the ax/eq intensity ratio occurs going from non-polar to polar solvents, with the ax conformer component that progressively decreases with respect to the eq one in CHCl3 and CH2Cl2, and is no longer detectable in the most polar solvent CH3CN. The PCM method applied to compound 4 supports these findings. In fact, it predicts the progressive increase of the eq/ax population ratio as the relative permittivity of the solvent increases. Moreover, it indicates that the computed νCO frequencies of the ax and eq conformers do not change in the non–polar solvents n-C6H14 and CCl4, while the νCO frequencies of the eq conformer become progressively lower than that of the ax one going from CHCl3 to CH2Cl2 and to CH3CN, in agreement with the experimental IR values. The analysis of the geometries of the ax and eq conformers shows that the carbonyl oxygen atom of the eq conformer is free for solvation, while the O[CO]…H[o-Ph] hydrogen bond that takes place in the ax conformer partially hinders the approach of the solvent molecules to the carbonyl oxygen atom. Therefore, the larger solvation that occurs in the carbonyl oxygen atom of the eq conformer is responsible for the observed and calculated decrease of the corresponding frequency. The X-ray single crystal analysis of 2 indicates that this compound adopts the most polar eq geometry in the solid. In fact, in order to obtain the largest energy gain, the molecules are arranged in the crystal in a helical fashion due to dipole moment coupling along with C-H…O and C-H…πPh hydrogen bonds.
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Affiliation(s)
- Paulo R. Olivato
- Conformational Analysis and Electronic Interactions Laboratory, Institute of Chemistry, University of São Paulo, USP, CP 26077, 05513-970 São Paulo, SP, Brazil; E-Mails: (J.M.M.S.); (B.C.); (C.R.C.); (D.N.S.R.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +55-11-3091-2167; Fax: +55-11-3815-5579
| | - Jean M. M. Santos
- Conformational Analysis and Electronic Interactions Laboratory, Institute of Chemistry, University of São Paulo, USP, CP 26077, 05513-970 São Paulo, SP, Brazil; E-Mails: (J.M.M.S.); (B.C.); (C.R.C.); (D.N.S.R.)
| | - Bruna Contieri
- Conformational Analysis and Electronic Interactions Laboratory, Institute of Chemistry, University of São Paulo, USP, CP 26077, 05513-970 São Paulo, SP, Brazil; E-Mails: (J.M.M.S.); (B.C.); (C.R.C.); (D.N.S.R.)
| | - Carlos R. Cerqueira
- Conformational Analysis and Electronic Interactions Laboratory, Institute of Chemistry, University of São Paulo, USP, CP 26077, 05513-970 São Paulo, SP, Brazil; E-Mails: (J.M.M.S.); (B.C.); (C.R.C.); (D.N.S.R.)
| | - Daniel N. S. Rodrigues
- Conformational Analysis and Electronic Interactions Laboratory, Institute of Chemistry, University of São Paulo, USP, CP 26077, 05513-970 São Paulo, SP, Brazil; E-Mails: (J.M.M.S.); (B.C.); (C.R.C.); (D.N.S.R.)
| | - Elisângela Vinhato
- Institute for Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, UNIFESP, Diadema 09972-270, SP, Brazil; E-Mail:
| | - Julio Zukerman-Schpector
- Chemistry Department, Federal University of São Carlos, CP 676, 13565-905, São Carlos, SP, Brazil; E-Mail:
| | - Maurizio Dal Colle
- Department of Chemistry, University of Ferrara, Ferrara 44100, Italy; E-Mail:
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8
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Olivato PR, Jr CRC, Contieri B, Santos JMM, Zukerman-Schpector J. Conformational preferences for some 3,3-bis[(4′-substituted phenylsulfanyl)]1-methyl-2-piperidinones through spectroscopic and theoretical studies. J Sulphur Chem 2013. [DOI: 10.1080/17415993.2013.771359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Paulo R. Olivato
- Instituto de Química, Universidade de São Paulo-USP, CP 26077, 05513-970 São Paulo, SP, Brazil
| | - Carlos R. Cerqueira Jr
- Instituto de Química, Universidade de São Paulo-USP, CP 26077, 05513-970 São Paulo, SP, Brazil
| | - Bruna Contieri
- Instituto de Química, Universidade de São Paulo-USP, CP 26077, 05513-970 São Paulo, SP, Brazil
| | - Jean M. M. Santos
- Instituto de Química, Universidade de São Paulo-USP, CP 26077, 05513-970 São Paulo, SP, Brazil
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Rozada TC, Gauze GF, Favaro DC, Rittner R, Basso EA. Infrared and theoretical calculations in 2-halocycloheptanones conformational analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 94:277-287. [PMID: 22534556 DOI: 10.1016/j.saa.2012.03.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/04/2012] [Accepted: 03/09/2012] [Indexed: 05/31/2023]
Abstract
2-Halocycloheptanones (Halo=F, Cl, Br and I) were synthesized and their conformational analysis was performed through infrared spectroscopy data. The corresponding conformers geometries and energies were obtained by theoretical calculations at B3LYP/aug-cc-pVDZ level of theory in the isolated state and in solution. It was observed, by both approaches, that the conformational preferences were very sensitive to the solvent polarity, since its increase led to an increase in the population of the more polar conformer. An analysis of these conformational equilibria showed they suffer also the influence of stereoelectronic effects, like hyperconjugation and steric effects. These results were interpreted using natural bond orbital (NBO) analysis, which indicated that the electronic delocalization to the orbital π*(C=O) is directly involved in the stability increase of conformers I and II. The relative effect of the period of the halogen can also be noted, with changes in the conformational preferences and in the energies involved in the interactions of NBO.
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Affiliation(s)
- Thiago C Rozada
- Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
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Azarakhshi F, Nori-Shargh D, Attar H, Masnabadi N, Yahyaei H, Mousavi SN, Boggs JE. Conformational behaviours of 2-substituted cyclohexanones: a complete basis set, hybrid-DFT study and NBO interpretation. MOLECULAR SIMULATION 2011. [DOI: 10.1080/08927022.2011.590986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Coelho JV, Freitas MP, Ramalho TC, Martins CR, Bitencourt M, Cormanich RA, Tormena CF, Rittner R. The case of infrared carbonyl stretching intensities of 2-bromocyclohexanone: Conformational and intermolecular interaction insights. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.05.097] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Coelho JV, Freitas MP. Orbital interactions in 2-halocyclohexanones as analyzed by means of theoretical calculations. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2009.10.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Olivato PR, Domingues NL, Reis AK, Vinhato E, Mondino MG, Zukerman-Schpector J, Rittner R, Colle MD. Spectroscopic and theoretical studies of some N-methoxy-N-methyl-2-[(4′-substituted) phenylsulfonyl]propanamides. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2009.06.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Tóth G, Hermecz I, Breining T, Mészáros Z, Bitter I. Stereochemistry and13C NMR investigation of 9-halotetrahydro-4H-pyrido[1,2-a]pyrimidin-4-ones. J Heterocycl Chem 2009. [DOI: 10.1002/jhet.5570200322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Spectroscopic and theoretical studies of some N-methoxy-N-methyl-2-[(4′-substituted) phenylthio]propanamides. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2008.11.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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The role of carbonyl and thiocarbonyl groups in the conformational isomerism of haloacetones and halothioacetones. Struct Chem 2008. [DOI: 10.1007/s11224-008-9348-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Substituent Effects on13C Chemical Shifts in Aliphatic Molecular Systems. Dependence on Constitution and Stereochemistry. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/9780470147252.ch4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
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Satyamurthy N, Blda GT, Padgett HC, Barrio JR. On the Stereoselectivity of Fluorine and Acetylhypofluorite Additions to Glycals: The Synthesis of 2-Deoxy-2-Fldorohexoses. J Carbohydr Chem 2007. [DOI: 10.1080/07328308508082672] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Olivato PR, Nanartonis R, Lopes JCD, Hase Y. CONFORMATIONAL AND ELECTRONIC INTERACTION STUDIES OF α-SUBSTITUTED CARBONYL COMPOUNDS. XII. S-ETHYL α-HETERO-SUBSTITUTED THIOACETATES. PHOSPHORUS SULFUR 2006. [DOI: 10.1080/10426509208034502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Paulo R. Olivato
- a Instituto de Química da Universidade de São Paulo , Caixa Postal 20.780, 01498 , São Paulo , S.P. , Brazil
| | - R. Nanartonis
- a Instituto de Química da Universidade de São Paulo , Caixa Postal 20.780, 01498 , São Paulo , S.P. , Brazil
| | - J. C. D. Lopes
- a Instituto de Química da Universidade de São Paulo , Caixa Postal 20.780, 01498 , São Paulo , S.P. , Brazil
| | - Yoshiyuki Hase
- b Instituto de Química, Universidade Estadual de Campinas , Caixa Postal 6154, 13081 , Campinas , S.P. , Brazil
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21
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Pontes RM, Fiorin BC, Basso EA. Understanding the conformational behavior of α-haloacetaldehydes: orbital interactions versus steric repulsion. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.066] [Citation(s) in RCA: 3] [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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22
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Tormena CF, Freitas MP, Rittner R, Abraham RJ. Theoretical and Infrared Investigation of the Conformations of 1,3-Dihaloacetones. J Phys Chem A 2004. [DOI: 10.1021/jp030864h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cláudio F. Tormena
- Physical Organic Chemistry Laboratory, Instituto de Química, UNICAMP, Caixa Postal 6154, 13084-971 Campinas, SP, Brazil, and Chemistry Department, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
| | - Matheus P. Freitas
- Physical Organic Chemistry Laboratory, Instituto de Química, UNICAMP, Caixa Postal 6154, 13084-971 Campinas, SP, Brazil, and Chemistry Department, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
| | - Roberto Rittner
- Physical Organic Chemistry Laboratory, Instituto de Química, UNICAMP, Caixa Postal 6154, 13084-971 Campinas, SP, Brazil, and Chemistry Department, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
| | - Raymond J. Abraham
- Physical Organic Chemistry Laboratory, Instituto de Química, UNICAMP, Caixa Postal 6154, 13084-971 Campinas, SP, Brazil, and Chemistry Department, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK
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23
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Rassat A. A classical approach to aromaticity and a new representation of benzene. Phys Chem Chem Phys 2004. [DOI: 10.1039/b312746j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Freitas MP, Tormena CF, Rittner R. Infrared spectroscopy and theoretical calculations as tools for the conformational analysis of 2-methoxycyclohexanone. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:1177-1182. [PMID: 12659886 DOI: 10.1016/s1386-1425(02)00316-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The conformational equilibrium of 2-methoxycyclohexanone has been analyzed through infrared spectroscopy and theoretical calculations. These calculations indicate that six conformations may be present in the vapor phase, due to the rotation of the methoxy group around the O-C(2) bond, leading to axial (g(+), g(-) and anti) and equatorial (g(+), g(-) and anti) conformers. However, the infrared spectrum in CCl(4) solution shows just three carbonyl stretching bands, corresponding to the conformers of lower energies. An additional band is observed for the CH(3)CN solution, attributed to a fourth conformer stabilized by a dipole-dipole interaction between this conformer, having a high dipole moment, and the very polar solvent. An interpretation of the governing factors of 2-methoxycyclohexanone equilibria is also given.
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Affiliation(s)
- M P Freitas
- Physical Organic Chemistry Laboratory, Instituto de Qui;mica, UNICAMP, Caixa Postal 6154, 13084-971, SP, Campinas, Brazil
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25
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Freitas MP, Tormena CF, Garcia JC, Rittner R, Abraham RJ, Basso EA, Santos FP, Cedran JC. NMR, solvation and theoretical investigations of conformational isomerism in 2-X-cyclohexanones (X=NMe2, OMe, SMe and SeMe). J PHYS ORG CHEM 2003. [DOI: 10.1002/poc.664] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Halogenated six-membered rings: a theoretical approach for substituent effects in conformational analysis. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0166-1280(02)00256-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Olivato P, Guerrero S, Yreijo M, Rittner R, Tormena C. Conformational and electronic interaction studies of 2-fluoro-substituted N,N-dimethylacetamides. J Mol Struct 2002. [DOI: 10.1016/s0022-2860(01)00761-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Freitas MP, Rittner R, Tormena CF, Abraham RJ. Conformational analysis of 2-bromocyclohexanone. A combined NMR, IR, solvation and theoretical approach. J PHYS ORG CHEM 2001. [DOI: 10.1002/poc.373] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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29
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Mcleod RG, Johnston BD, Pinto BM. A generalizedexo-anomeric effect. Substituent and solvent effects on the conformational equilibria of 2-(arylseleno)cyclohexanones. Isr J Chem 2000. [DOI: 10.1560/gyn6-1prq-6kgf-0lva] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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30
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Wolfe S, Shi Z. The SCO (OCS) edward-lemieux effect is controlled by a P-orbital on oxygen. Evidence from electron momentum spectroscopy, photoelectron spectroscopy, X-ray crystallography, and density functional theory. Isr J Chem 2000. [DOI: 10.1560/dy9j-0f0n-uuy5-7clb] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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31
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Omoto K, Marusaki K, Hirao H, Imade M, Fujimoto H. Theoretical Study of the Anomeric Effect in CH2ClOH. J Phys Chem A 2000. [DOI: 10.1021/jp994165+] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Anderson JE. Why Do so Few Simple Acyclic Acetals Adopt the Classic Anomeric Conformation? The Eclipsed Anomeric Conformation for Acetals. An Analysis of Crystal Structures, Molecular Mechanics Calculations, and NMR Measurements. J Org Chem 2000. [DOI: 10.1021/jo991553z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Edgar Anderson
- Chemistry Department, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Pridgen LN, De Brosse C. Reliable (13)C NMR Method of Making Relative Stereochemical Assignments to Certain N-[alpha-Hetero-beta-hydroxy(acetoxy)-beta-(substituted phenyl)-1'-oxopropyl]-2-oxazolidinones. J Org Chem 1997; 62:216-220. [PMID: 11671387 DOI: 10.1021/jo951798l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lendon N. Pridgen
- Synthetic Chemistry Department, Chemical, R&D, SmithKline & Beecham Pharmaceuticals Post Office Box 1539, King of Prussia, Pennsylvania 19406
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Paquette LA, Lobben PC. π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone). J Am Chem Soc 1996. [DOI: 10.1021/ja9536835] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leo A. Paquette
- Contribution from the Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210
| | - Paul C. Lobben
- Contribution from the Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210
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Erdem SS, Varnali T, Aviyente V, Ruiz-Lopez M. Solvent effect on the conformational behavior of substituted spiro[4.5]decanes and spiro[5.5]undecanes. CAN J CHEM 1995. [DOI: 10.1139/v95-089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied the relatively complex polar systems 6-substituted-1,4-dioxospiro[4.5]decanes and 7-substituted-1,5-dioxospiro[5.5]undecanes with substituents X = CH3, F, Cl, CN, OH, OCH3, and NO2. Solvent effects on the equilibrium have been analysed by means of a Self-Consistent-Reaction-Field model and the PM3 method. Complete geometry optimizations have been carried out for all the structures in the gas phase and in solution. For some substituents, a set of rotamers have been separately optimized. The discussion of the results is focussed on the effects arising from structural aspects and from steric and electrostatic interactions on the axial/equatorial relative stability. The role played by multipole moment is considered. In general, good agreement with available experimental data and with previous theoretical studies has been obtained. Though the use of semiempirical methods and simple solvent models prevents us from reaching definitive conclusions, this approach seems to be very useful in predicting the main role of solute–solvent interactions in conformational equilibria of complex systems for which ab initio calculations cannot be performed. Keywords: conformational equilibria, spiro decanes and undecanes, cavity model, SCRF, solvent effect, PM3 calculations.
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Fraser RR, Faibish NC. On the purported axial preference in 2-methylthio and 2-methoxycyclohex-anones: steric effects versus orbital interactions. CAN J CHEM 1995. [DOI: 10.1139/v95-013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The value for the equilibrium constant representing the ratio of equatorial to axial conformers for 2-methylthio- and 2-methoxycyclohexanone has been measured in five solvents using 500 MHz 1H nuclear magnetic resonance. In cyclohexane solvent, the methylthio group is found to have a large axial preference while that for the methoxy is negligible. For both compounds the equilibrium shows a strong solvent dependence. Comparison of these results with those known for the halo derivatives shows the amount of axial to increase in the order: fluoro, methoxy, chloro, bromo, and methylthio. With the aid of molecular mechanics calculations it is concluded that the order of conformational preference can be attributed to a variation in the van der Waals interaction between the substituent and the carbonyl group in the equatorial conformer. Keywords: α-substituted cyclohexanones, conformation, MMX calculations, steric and dipolar effects.
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Varnali T, Aviyente V, Ruiz-Lopez MF. 2-Nitroethanal conformations in solution: AnAb initio SCRF study. Struct Chem 1994. [DOI: 10.1007/bf02252893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Olivato PR, Filho RR, Lopes JCD. Conformational And Electronic Interaction Studies Of 2-Seleno-Substituted Carbonyl Compounds And The Comparison With The 2-Thio-Analogues. XIII. α-Phenylseleno-p-Substituted Propiophenones1. PHOSPHORUS SULFUR 1994. [DOI: 10.1080/10426509408021463] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Tostes J, de M. Carneiro J, Lie S, Seidl P, Taft C, Soto M, Lester W, Hammond B. Hyperconjugation and charge distribution in alicyclic alcohols and exo- and endo-norbornol. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0166-1280(94)80032-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Conformational equilibria of α-substituted carbonyl compounds. Study of solvent effects. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0166-1280(93)80003-i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Laing M. The ?-bromocyclohexanone ring: The relationship between its conformation and the ultraviolet and infrared absorption of the keto group. J PHYS ORG CHEM 1991. [DOI: 10.1002/poc.610040705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Tsipis C. Theoretical approaches to the description of the electronic structure and chemical reactivity of transition metal compounds. Coord Chem Rev 1991. [DOI: 10.1016/0010-8545(91)84002-m] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Crich D, Lim LBL. Diastereoselective free-radical reactions. Part 2. Synthesis of 2-deoxy-β-C-pyranosides by diastereoselective hydrogen-atom transfer. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/p19910002205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Magnus P, Lacour J, Bauta W, Mugrage B, Lyncht V. Thermodynamically preferred axial allylic –NHTs substituent in simple l-triisopropylsilyl(oxy) cyclohexenes: solid state conformation by X-ray crystallography. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/c39910001362] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Senderowitz H, Aped P, Fuchs B. Probing the Anomeric Effect in O?C?N Systems Theoryvs. Experiment: MO-ab initio Calculations and a Structural-Statistical Analysis. Helv Chim Acta 1990. [DOI: 10.1002/hlca.19900730807] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Schleifer L, Senderowitz H, Aped P, Tartakovsky E, Fuchs B. Diagnostic structural criteria for the anomeric effect in carbohydrates and inferences of general significance on their scope and limitations. Carbohydr Res 1990. [DOI: 10.1016/0008-6215(90)84003-d] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Stanley J, Matallana A, Kingsbury CA. Correlation of molecular mechanics and NMR data: Conformation and configuration of the Meerwein lactones. J PHYS ORG CHEM 1990. [DOI: 10.1002/poc.610030702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Olivato PR, Guerrero SA, Hase Y, Rittner R. Conformational and electronic interaction studies of α-substituted carbonyl compounds. Part 9. ω-Hetero-substituted acetophenones. ACTA ACUST UNITED AC 1990. [DOI: 10.1039/p29900000465] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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