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Volumn 72, Issue 3, 2007, Pages 998-1004

Conformation and stereodynamics of symmetrically ortho-disubstituted aryl carbinols and aryl ethers

Author keywords

[No Author keywords available]

Indexed keywords

AB INITIO COMPUTATIONS; ORTHO-DISUBSTITUTED ARYL CARBINOLS; STEREODYNAMICS; TRANSITION STATES;

EID: 33846906941     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo062289u     Document Type: Article
Times cited : (6)

References (65)
  • 1
    • 33846931956 scopus 로고    scopus 로고
    • In partial fulfillment for the Ph.D. in Chemical Sciences, University of Bologna
    • In partial fulfillment for the Ph.D. in Chemical Sciences, University of Bologna.
  • 19
    • 33846910135 scopus 로고    scopus 로고
    • Program Gaussian 03, Revision D.01. Frisch, M. J, Trucks, G. W, Schlegel, H. B, Scuseria, G. E, Robb, M. A, Cheeseman, J. R, Montgomery, Jr, J. A, Vreven, T, Kudin, K. N, Burant, J. C, Millam, J. M, Iyengar, S. S, Tomasi, J, Barone, V, Mennucci, B, Cossi, M, Scalmani, G, Rega, N, Petersson, G. A, Nakatsuji, H, Hada, M, Ehara, M, Toyota, K, Fukuda, R, Hasegawa, J, Ishida, M, Nakajima, T, Honda, Y, Kitao, O, Nakai, H, Klene, M, Li, X, Knox, J. E, Hratchian, H. P, Cross, J. B, Bakken, V, Adamo, C, Jaramillo, J, Gomperts, R, Stratmann, R. E, Yazyev, O, Austin, A. J, Cammi, R, Pomelli, C, Ochterski, J. W, Ayala, P. Y, Morokuma, K, Voth, G. A, Salvador, P, Dannenberg, J. J, Zakrzewski, V. G, Dapprich, S, Daniels, A. D, Strain, M. C, Farkas, O, Malick, D. K, Rabuck, A. D, Raghavachari, K, Foresman, J. B, Ortiz, J. V, Cui, Q, Baboul, A. G, Clifford, S, Cioslowski, J, Stefanov, B. B, Liu, G, Liashenko, A, Piskorz, P, Komaromi
    • Program Gaussian 03, Revision D.01. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, Jr., J. A.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian, Inc., Wallingford CT, 2004.
  • 20
    • 33846905886 scopus 로고    scopus 로고
    • MMX force field as in PC Model v 7.5, Serena Software, Bloomington, IN.
    • MMX force field as in PC Model v 7.5, Serena Software, Bloomington, IN.
  • 22
    • 0011661941 scopus 로고    scopus 로고
    • This result is at variance with the hypothesis of Schaefer et al, which arbitrarily assumed conformation C to be the ground state. See: Schaefer, T, Sebastian, R, Penner, G. H, Salman, S. R. Can. J. Chem. 1986, 64, 1602
    • This result is at variance with the hypothesis of Schaefer et al., which arbitrarily assumed conformation C to be the ground state. See: Schaefer, T.; Sebastian, R.; Penner, G. H.; Salman, S. R. Can. J. Chem. 1986, 64, 1602.
  • 23
    • 33846901744 scopus 로고    scopus 로고
    • As shown in Scheme 2, the computed dihedral angle between the aromatic ring and the plane defined by the Cl-C-O moiety of 1 is 48° for the most stable conformer B and 28° for the transition state interconverting B into A, i.e., the process which is responsible for the too fast interconversion of the +sc and -sc enantiomers.
    • As shown in Scheme 2, the computed dihedral angle between the aromatic ring and the plane defined by the Cl-C-O moiety of 1 is 48° for the most stable conformer B and 28° for the transition state interconverting B into A, i.e., the process which is responsible for the too fast interconversion of the +sc and -sc enantiomers.
  • 24
    • 33846924699 scopus 로고    scopus 로고
    • 13C signals of 1 should likewise split into a pair of lines: this feature, however, was not observed since the corresponding shift separations were smaller than the line width, which is very broad below -160°C.
    • 13C signals of 1 should likewise split into a pair of lines: this feature, however, was not observed since the corresponding shift separations were smaller than the line width, which is very broad below -160°C.
  • 25
    • 33846918568 scopus 로고    scopus 로고
    • PC version of QCPE program DNMR 6 no. 633, Indiana University, Bloomington, IN.
    • PC version of QCPE program DNMR 6 no. 633, Indiana University, Bloomington, IN.
  • 26
    • 33846939434 scopus 로고    scopus 로고
    • 19F lines at such low temperatures.
    • 19F lines at such low temperatures.
  • 27
    • 33846922443 scopus 로고    scopus 로고
    • The inversion of the relative stability of two conformers when the ethyl groups substitute the methyl groups had been well documented in analogous cases see ref. 10
    • The inversion of the relative stability of two conformers when the ethyl groups substitute the methyl groups had been well documented in analogous cases (see ref. 10).
  • 28
    • 0343771937 scopus 로고    scopus 로고
    • The interconversion between the two conformers of type A and B also involves a simultaneous rearrangement of the two ethyl groups: such a rearrangement contributes to determine the value of the measured barrier of 5 kcal mol-1 (the corresponding ab initio computed barrier of 4.4 kcal mol-1 agrees well with the experiment, In the more stable conformer of type A, in fact, the two ethyl groups adopt a symmetric relative disposition (see the computed structure in the Supporting Information, Figure S-2, in agreement with the observation of a single CH2 line in the mentioned 13C spectrum at the -172°C. In the less stable conformer of type B, on the other hand, one of the two ethyl groups adopts a disposition different form that of its companion also this the computed structure is displayed in the Supporting Information, Figure S-2, The existence of symmetric and asymmetric conformers due to the relative disposition of two ethyl groups has b
    • 8
  • 29
    • 33846899374 scopus 로고    scopus 로고
    • 1H signal (600 MHz) of the o-methyl substituents.
    • 1H signal (600 MHz) of the o-methyl substituents.
  • 30
    • 33846920975 scopus 로고    scopus 로고
    • As often observed in conformational process, the ΔG‡ value was found independent of temperature within the experimental uncertainty of the NMR measurements. See: Hoogosian, S.; Bushweller, C. H.; Anderson, W. G.; Kigsley, G. J. Phys. Chem. 1976, 80, 643.
    • As often observed in conformational process, the ΔG‡ value was found independent of temperature within the experimental uncertainty of the NMR measurements. See: Hoogosian, S.; Bushweller, C. H.; Anderson, W. G.; Kigsley, G. J. Phys. Chem. 1976, 80, 643.
  • 46
    • 33847087228 scopus 로고    scopus 로고
    • It should be outlined that the present result is at variance with the report of another pair of biphenyl derivatives, where the o-methyl- substituted compound displayed a rotation barrier 0.5 kcal mol-1 higher than that of the corresponding chlorine derivative. See: Bott, G, Field, L. D, Sternhell, S. J. Am. Chem. Soc. 1980, 102, 5618
    • -1 higher than that of the corresponding chlorine derivative. See: Bott, G.; Field, L. D.; Sternhell, S. J. Am. Chem. Soc. 1980, 102, 5618.
  • 47
    • 33947300443 scopus 로고
    • a minimum of 1.715 and a maximum of 2.23; see: Charton, M
    • Two values were indicated for the van der Waals radii of the methyl group
    • Two values were indicated for the van der Waals radii of the methyl group: a minimum of 1.715 and a maximum of 2.23; see: Charton, M. J. Am. Chem. Soc. 1969, 91, 615.
    • (1969) J. Am. Chem. Soc , vol.91 , pp. 615
  • 48
    • 33846907700 scopus 로고    scopus 로고
    • Ab inito calculations of the whole energy surface exceeded the capabilities of our computing facilities; thus, only the optimized singular points (ground and transition states) were computed see the Experimental Section and Supporting Information
    • Ab inito calculations of the whole energy surface exceeded the capabilities of our computing facilities; thus, only the optimized singular points (ground and transition states) were computed (see the Experimental Section and Supporting Information).
  • 49
    • 0001681329 scopus 로고    scopus 로고
    • Examples of NMR determinations of very low barriers can be found in: Anet, F. A. L.; Chmurny, G. N.; Krane, J. J. Am. Chem. Soc. 1973, 95, 4423.
    • Examples of NMR determinations of very low barriers can be found in: Anet, F. A. L.; Chmurny, G. N.; Krane, J. J. Am. Chem. Soc. 1973, 95, 4423.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.