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1
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33846931956
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In partial fulfillment for the Ph.D. in Chemical Sciences, University of Bologna
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In partial fulfillment for the Ph.D. in Chemical Sciences, University of Bologna.
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4
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1542457699
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Baas, J. M. A.; van der Toorn, J. M.; Wepster, B. M. Recl. Trav. Chim. Pays-Bas 1974, 93, 173.
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Recl. Trav. Chim. Pays-Bas
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Baas, J.M.A.1
van der Toorn, J.M.2
Wepster, B.M.3
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5
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84971061938
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Landman, D.; Newsoroff, G. P.; Sternhell, S. Aust. J. Chem. 1972, 25, 109.
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Aust. J. Chem
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Landman, D.1
Newsoroff, G.P.2
Sternhell, S.3
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6
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0000876050
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Suezawa, H.; Wada, H.; Watanabe, H.; Yuzuri, T.; Sakakibara, K.; Hirota, M. J. Phys. Org. Chem. 1997, 10, 925.
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J. Phys. Org. Chem
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Suezawa, H.1
Wada, H.2
Watanabe, H.3
Yuzuri, T.4
Sakakibara, K.5
Hirota, M.6
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9
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0000179789
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(b) Lomas, J. S.; Luong, P. K.; Dubois, J.-E. J. Org. Chem. 1977, 42, 3394.
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J. Org. Chem
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Lomas, J.S.1
Luong, P.K.2
Dubois, J.-E.3
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14
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37049081617
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Anderson, J. E.; Bru-Capdeville, V.; Kirsch, P. A.; Lomas, J. S. Chem. Commun. 1994, 1077.
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Chem. Commun
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Anderson, J.E.1
Bru-Capdeville, V.2
Kirsch, P.A.3
Lomas, J.S.4
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1542398459
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Casarini, D.; Lunazzi, L.; Mazzanti, A. J. Org. Chem. 1997, 62, 3315.
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J. Org. Chem
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Casarini, D.1
Lunazzi, L.2
Mazzanti, A.3
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17
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0037131765
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Wolf, C.; Pranatharthiharan, L.; Ramagosa, R. B. Tetrahedron Lett. 2002, 43, 8563.
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Tetrahedron Lett
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Wolf, C.1
Pranatharthiharan, L.2
Ramagosa, R.B.3
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18
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20844448412
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Casarini, D.; Coluccini, C.; Lunazzi, L.; Mazzanti, A. J. Org. Chem. 2005, 70, 5098.
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J. Org. Chem
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Casarini, D.1
Coluccini, C.2
Lunazzi, L.3
Mazzanti, A.4
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19
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33846910135
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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
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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.
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20
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33846905886
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MMX force field as in PC Model v 7.5, Serena Software, Bloomington, IN.
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MMX force field as in PC Model v 7.5, Serena Software, Bloomington, IN.
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22
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0011661941
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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
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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.
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23
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33846901744
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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.
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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.
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24
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33846924699
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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.
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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.
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25
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33846918568
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PC version of QCPE program DNMR 6 no. 633, Indiana University, Bloomington, IN.
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PC version of QCPE program DNMR 6 no. 633, Indiana University, Bloomington, IN.
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26
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33846939434
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19F lines at such low temperatures.
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19F lines at such low temperatures.
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27
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33846922443
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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
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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).
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28
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0343771937
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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
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8
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29
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33846899374
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1H signal (600 MHz) of the o-methyl substituents.
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1H signal (600 MHz) of the o-methyl substituents.
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33846920975
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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.
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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.
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0000467345
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Lunazzi, L.; Cerioni, G.; lngold, K. U. J. Am. Chem. Soc. 1976, 98, 7484.
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Lunazzi, L.1
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0000263988
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Bernardi, F.; Lunazzi, L.; Zanirato, P.; Cerioni, G. Tetrahedron 1977, 33, 1337.
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Bernardi, F.1
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0002093524
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Lunazzi, L.; Magagnoli, C.; Guerra, M.; Macciantelli, D. Tetrahedron Lett. 1979, 3031.
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Lunazzi, L.1
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Macciantelli, D.4
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35
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0025171385
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Cremonini, M. A.; Lunazzi, L.; Placucci, G.; Okazaki, R.; Yamamoto, G. J. Am. Chem. Soc. 1990, 112, 2915.
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0001456326
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Anderson, J. E.; Tocher, D. A.; Casarini, D.; Lunazzi, L. J. Org. Chem. 1991, 56, 1731.
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0030793709
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Borghi, R.; Lunazzi, L.; Placucci, G.; Cerioni, G.; Foresti, E.; Plumitallo, A. J. Org. Chem. 1997, 62, 4924.
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0035812798
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0036898427
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0345871941
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Mazzanti, A.1
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Anderson, J.E.4
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33847087228
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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
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-1 higher than that of the corresponding chlorine derivative. See: Bott, G.; Field, L. D.; Sternhell, S. J. Am. Chem. Soc. 1980, 102, 5618.
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47
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33947300443
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a minimum of 1.715 and a maximum of 2.23; see: Charton, M
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Two values were indicated for the van der Waals radii of the methyl group
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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.
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(1969)
J. Am. Chem. Soc
, vol.91
, pp. 615
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48
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33846907700
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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
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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).
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0001681329
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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.
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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.
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