-
10
-
-
2642663050
-
-
note
-
N2 reactions has been well documented; however, their early appearance on the reaction coordinate may not have been appreciated.
-
-
-
-
11
-
-
2642627241
-
-
note
-
The destabilization results from a 1,3 repulsive interaction (nucelophile/α-carbon) in the cyclization substrate. Wiberg and Bauld have discussed this type of interaction and the resulting destabilization previously. We will present a detailed analysis soon.
-
-
-
-
13
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2642684112
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Bauld, N. L.; Cessac, J.; Holloway, R. L. J. Am. Chem. Soc. 1977, 99, 8141.
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Bauld, N.L.1
Cessac, J.2
Holloway, R.L.3
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14
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Gaussian, Inc., Pittsburgh, PA
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Gaussian 92: Frisch, M. J.; Trucks, G. W.; Head-Gordon, M.; Gill, P. M. W.; Wong, M. H.; Foresman, J., B,; Johnson, B. D.; Schlegel, H. B.; Robb, M. A.; Replogle, E. S.; Gomperts, R.; Anfres, J. L.; Raghavachari, K.; Binkley, J. S.; Gonzalez, C.; Martin, R. L.; Fox, D. J.; DeFrees, D. J.; Baker, J. J. P.; Pople, J. A. Gaussian, Inc., Pittsburgh, PA, 1992.
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Frisch, M.J.1
Trucks, G.W.2
Head-Gordon, M.3
Gill, P.M.W.4
Wong, M.H.5
Foresman, J.B.6
Johnson, B.D.7
Schlegel, H.B.8
Robb, M.A.9
Replogle, E.S.10
Gomperts, R.11
Anfres, J.L.12
Raghavachari, K.13
Binkley, J.S.14
Gonzalez, C.15
Martin, R.L.16
Fox, D.J.17
DeFrees, D.J.18
Baker, J.J.P.19
Pople, J.A.20
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15
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Gaussian 94: Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; W. Gill, P. M.; Johnson, B. G.; Robb, M. A.; Cheeseman, J. R.; Keith, T.; Petersson, G. A.; Montgomery, J. A.; Raghavachari, K.; Al-Laham, M. A.; Zakrzewski, V. G.; Ortiz, J. V.; Foresman, J. B.; Peng, C. Y.; Ayala, P. Y.; Chen, W.; Wong, M. W.; Andres, J. L.; Replogle, E. S.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Binkley, J. S.; Defrees, D. J.; Baker, J.; Stewart, J. P.; Head-Gordon, M.; Gonzalez, C.; Pople, J. A. Gaussian, Inc., Pittsburgh, PA, 1995.
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Frisch, M.J.1
Trucks, G.W.2
Schlegel, H.B.3
W. Gill, P.M.4
Johnson, B.G.5
Robb, M.A.6
Cheeseman, J.R.7
Keith, T.8
Petersson, G.A.9
Montgomery, J.A.10
Raghavachari, K.11
Al-Laham, M.A.12
Zakrzewski, V.G.13
Ortiz, J.V.14
Foresman, J.B.15
Peng, C.Y.16
Ayala, P.Y.17
Chen, W.18
Wong, M.W.19
Andres, J.L.20
Replogle, E.S.21
Gomperts, R.22
Martin, R.L.23
Fox, D.J.24
Binkley, J.S.25
Defrees, D.J.26
Baker, J.27
Stewart, J.P.28
Head-Gordon, M.29
Gonzalez, C.30
Pople, J.A.31
more..
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85005470381
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Pople, I.A.1
Scott, A.P.2
Wong, M.W.3
Radom, L.4
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17
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0041401966
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Curtiss, L. A.; Raghavachari, K.; Trucks, G. W.; Pople, J. A. J. Chem. Phys. 1991, 94, 7221.
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, vol.94
, pp. 7221
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Curtiss, L.A.1
Raghavachari, K.2
Trucks, G.W.3
Pople, J.A.4
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18
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0001206228
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Merrill, G.N.2
Kass, S.R.3
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19
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0003450764
-
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Mallard, W. G., Linstrom, P. J., Eds.; National Institute of Standards and Technology Gaithersburg, MD
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Afeefy, H. Y.; Liebman, J. F.; Stein, S. E. In NIST Standard Reference Database Number 69; Mallard, W. G., Linstrom, P. J., Eds.; National Institute of Standards and Technology (http://webbook.nist.gov): Gaithersburg, MD, 1997.
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NIST Standard Reference Database Number 69
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Afeefy, H.Y.1
Liebman, J.F.2
Stein, S.E.3
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20
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0003450764
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Mallard, W. G., Linstrom, P. J., Eds.; National Institute of Standards and Technology (http://webbook.nist.gov): Gaithersburg, MD
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Bartmess, J. E. In NIST Standard Reference Database Number 69; Mallard, W. G., Linstrom, P. J., Eds.; National Institute of Standards and Technology (http://webbook.nist.gov): Gaithersburg, MD, 1997.
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NIST Standard Reference Database Number 69
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-
Bartmess, J.E.1
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21
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2642695281
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-
note
-
In fact, we started with a geometry where the carbanion interacted most strongly with the methyl chloride but it relaxed to IVid.
-
-
-
-
22
-
-
2642630288
-
-
note
-
In each case, it is assumed that the strain in the substituted system is similar to the parent (cyclopropane). Available thermochemistry indicates that this will introduce only a small error; see ref 19.
-
-
-
-
23
-
-
2642623165
-
-
note
-
- → IVr. For these calculations, the separated reactants are used as the ground state in each case, but the ring-opening transition state is favored by more than the entire ring strain of Ip. As a result, a factor other than ring strain must be at work.
-
-
-
-
24
-
-
2642604804
-
-
note
-
- was investigated, and similar barriers were found for the formation of 1,2-butadiene and 1-butyne.
-
-
-
-
25
-
-
2642690237
-
-
note
-
Examples have been reported where cyclizations to three-membered rings have large entropic advantages (>20 eu); however, these are undoubtedly the result of solvation effects.
-
-
-
-
26
-
-
2642596664
-
-
note
-
N2 reaction; however, the proximity effect is still significant (it can provide nearly 50% of the free-energy advantage).
-
-
-
-
27
-
-
2642657898
-
-
note
-
The difference is not the result of additional angle strain in the cyclization transition state. The O-C-C angle is about the same as the C-C-C angles in the carbanion systems. In fact it is wider than the C-C-C angle in the enolate system.
-
-
-
-
29
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-
37049124408
-
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Bird, R.; Knipe, A. C.; Stirling, C. J. M. J. Chem. Soc., Perkin Trans 2 1973, 1215.
-
(1973)
J. Chem. Soc., Perkin Trans 2
, pp. 1215
-
-
Bird, R.1
Knipe, A.C.2
Stirling, C.J.M.3
-
32
-
-
2642655883
-
-
note
-
We have shown that four-and five-membered rings do not benefit from the proximity effect. See ref 1.
-
-
-
-
39
-
-
2642626209
-
-
Cannon, G. W.; Ellis, R. C.; Leal, J. R. Org. Synth. 1951, 31, 74.
-
(1951)
Org. Synth.
, vol.31
, pp. 74
-
-
Cannon, G.W.1
Ellis, R.C.2
Leal, J.R.3
-
43
-
-
2142698268
-
-
Heine, H. W.; Miller, A. D.; Barton, W. H.; Greiner, R. W. J. Am. Chem. Soc. 1953, 75, 4778.
-
(1953)
J. Am. Chem. Soc.
, vol.75
, pp. 4778
-
-
Heine, H.W.1
Miller, A.D.2
Barton, W.H.3
Greiner, R.W.4
-
46
-
-
2642593604
-
-
note
-
In fact, it is difficult to find exceptions. One exception involves systems where an aniline nitrogen is the nucleophile - a higher rate constant for forming a three-membered ring is observed. However, delocalization is possible, and therefore, it is not surprising that they do not behave like simple amines. See ref 29.
-
-
-
-
47
-
-
2642653807
-
-
note
-
All the cyclizations to three-membered rings have an entropy advantage. It is the shift in preference from five-membered rings to three-membered rings that involves the proximity effect.
-
-
-
-
48
-
-
85027472609
-
-
Ruzicka, L.; Brugger, W.; Pfeiffer, M.; Schinz, H.; Stoll, M. Helv. Chim. Acta 1926, 9, 499.
-
(1926)
Helv. Chim. Acta
, vol.9
, pp. 499
-
-
Ruzicka, L.1
Brugger, W.2
Pfeiffer, M.3
Schinz, H.4
Stoll, M.5
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