Stereochemistry and conformational anomalies of 1,2,3- and 1,2,3,4-polycyclohexylcyclohexanes

Journal of the American Chemical Society

Volumn 118, Issue 29, 1996, Pages 6890-6896

  Columbus, Ishay ^a   Hoffman, Roy E ^a   Biali, Silvio E ^a  

^a HEBREW UNIVERSITY OF JERUSALEM   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

CYCLOHEXANE DERIVATIVE;

ARTICLE; CATALYSIS; CONFORMATION; HYDROGENATION; ISOMERISM; STEREOCHEMISTRY;

EID: 0029955317     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja960380h     Document Type: Article

References (40)

1. Eliel, E. L.; Wilen, S. H. Stereochemistry of Organic Compounds; Wiley: New York, 1994.
2. Conformational Behavior of Six Membered Rings, Juaristi, E., Ed.; VCH Publishers: New York, 1995. Kellie, G. M.; Riddell, F. G. Top. Stereochem. 1974, 8, 225.
3. Conformational Behavior of Six Membered Rings, Juaristi, E., Ed.; VCH Publishers: New York, 1995. Kellie, G. M.; Riddell, F. G. Top. Stereochem. 1974, 8, 225.
4. For a review on conformational flexible hydrocarbons, see: Hoffmann, R. W. Angew. Chem., Int. Ed. Engl. 1992, 31, 1124.
5. Arbitrarily, we will denote dihedral angles in the range of ±(60-40°), ±(40-20°), and ±(20-0°) as "staggered", "nonstaggered", and "eclipsed", respectively. The terms anti and gauche will be used taking the methine protons of the central ring and the substituents as the reference groups.
6. Immirzi, A.; Torti, E. Atti. Accad. Naz. Lincei Cl. Sci. Fis., Mat. Nat. Rend. 1968, 44, 98.
7. Golan, O.; Goren, Z.; Biali, S. E. J. Am. Chem. Soc. 1990, 112, 9300.
8. For studies on polycyclohexyl systems, see: (a) Hoffman, R. W.; Sander, T.; Brumm, M. Chem. Ber. 1992, 125, 2319. (b) Columbus, I.; Biali, S. E. J. Org. Chem. 1993, 58, 7029.
9. For studies on polycyclohexyl systems, see: (a) Hoffman, R. W.; Sander, T.; Brumm, M. Chem. Ber. 1992, 125, 2319. (b) Columbus, I.; Biali, S. E. J. Org. Chem. 1993, 58, 7029.
10. For a preliminary communication, see: Columbus, I. ; Cohen, S. ; Biali, S. E. J. Am. Chem. Soc. 1994, 116, 10306.
11. All pressures refer to the initial hydrogen pressures at room temperature.
12. For a study on the mutual isomerization of polysubstituted cyclohexanes, see: Farina, M. Grassi, M.; Di Silvestro, G. J. Am. Chem. Soc. 1985, 107, 5100.
13. Günther, H. NMR Spectroscopy; Wiley: Chichester, 1980; (a) p 106; (b) p 72.
14. Günther, H. NMR Spectroscopy; Wiley: Chichester, 1980; (a) p 106; (b) p 72.
15. For a review on 2D NMR techniques, see: Kessler, H.; Gehrke, M.; Griesinger, M. Angew. Chem., Int. Ed. Engl. 1988, 27, 490.
16. 13C NMR Spectroscopy, 2nd ed.; Verlag Chemie: Weinheim, 1978; p 71.
17. Obviously, the locations of the substituents are complementary to those of the methine protons; i.e., if a given methine proton is axial, the substituent attached to that methine group must be equatorial.
18. Mislow, K. Chimia 1986, 40, 395. Biali, S. E.; Buda, A. B.; Mislow, K. J. Org. Chem. 1988, 53, 1289.
19. Mislow, K. Chimia 1986, 40, 395. Biali, S. E.; Buda, A. B.; Mislow, K. J. Org. Chem. 1988, 53, 1289.
20. See for example: Siegel, J.; Gutierrez, A.; Schweizer, W. B.; Ermer, O.; Mislow, K. J. Am. Chem. Soc. 1986, 108, 1569. Bomse, D. S.; Morton, T. H. Tetrahedron Lett. 1975, 781.
21. See for example: Siegel, J.; Gutierrez, A.; Schweizer, W. B.; Ermer, O.; Mislow, K. J. Am. Chem. Soc. 1986, 108, 1569. Bomse, D. S.; Morton, T. H. Tetrahedron Lett. 1975, 781.
22. Siegel, J. S.; Anet, F. A. L. J. Org. Chem. 1988, 53, 2629.
23. The exchange rates at the coalescence temperatures were calculated according to Gutowski, H. S.; Holm, C. H. J. Chem. Phys. 1956, 25, 1228.
24. Allinger, N. L. Molecular Mechanics. Operating Instructions for the MM3 Program. 1989 Force Field (updated 5/6/92); Technical Utilization Corp.
25. Statically geared systems may possess high rotational barriers. See for example: Biali, S. E.; Mislow, K. J. Org. Chem. 1988, 53, 1318.
26. MacKenzie, K. J. Chem. Soc. 1960, 473.
27. The crystallographic data of 6 are described in ref 8.
28. One of the "ortho" equatorial protons on the axial substituent (H-2″e or H-6″e) is shifted upfield (1.35 ppm). This signal is assigned to the proton located above the central cyclohexyl ring. A similar shielding effect is not observed in all-cis-3, since even at 150 K there is a fast enantiomerization process on the NMR time scale which renders the two edges of the axial ring equivalent (cf. Figure 3).
29. Wieser, J.; Golan O.; Fitjer, L.; Biali, S. E. unpublished results.
30. The substituent in monoalkyl-substituted cyclohexanes always prefers an equatorial position. For an exception, see: Biali, S. E. J. Org. Chem. 1992, 57, 2979.
31. Seiler, P.; Weisman, G. R.; Glendening, E. D.; Weinhold, F.; Johnson, J. D.; Dunitz, J. D. Angew. Chem., Int. Ed. Engl. 1987, 26, 1175.
32. Juaristi, E.; Martinez, R.; Mendez, R.; Toscano, R. A.; Soriano-Garcia, M.; Eliel, E. L.; Petson, A.; Glass, R. S. J. Org. Chem. 1987, 52, 3806. Anderson, J. E. J. Chem. Soc., Perkin Trans. 2 1992, 1343. Anderson, J. E.; Watson, D. G. J. Am. Chem. Soc. 1992, 114, 1517.
33. Juaristi, E.; Martinez, R.; Mendez, R.; Toscano, R. A.; Soriano-Garcia, M.; Eliel, E. L.; Petson, A.; Glass, R. S. J. Org. Chem. 1987, 52, 3806. Anderson, J. E. J. Chem. Soc., Perkin Trans. 2 1992, 1343. Anderson, J. E.; Watson, D. G. J. Am. Chem. Soc. 1992, 114, 1517.
34. Juaristi, E.; Martinez, R.; Mendez, R.; Toscano, R. A.; Soriano-Garcia, M.; Eliel, E. L.; Petson, A.; Glass, R. S. J. Org. Chem. 1987, 52, 3806. Anderson, J. E. J. Chem. Soc., Perkin Trans. 2 1992, 1343. Anderson, J. E.; Watson, D. G. J. Am. Chem. Soc. 1992, 114, 1517.
35. Forsyth, D. A.; Johnson, S. M. J. Am. Chem. Soc. 1993, 115, 3364.
36. In the lowest energy conformation of propene one of the C-H bonds is eclipsed with the double bond.
37. For studies on isopropyl groups attached to a saturated carbon, see: Anderson, J. E.; Koon, K. H.; Parkin, J. E. Tetrahedron 1985, 41, 561.
38. 2. According to the calculations, in the gear-meshed all-equatorial conformation of all-trans-1,2,3,4,5,6-hexacyclohexylcyclohexane this angle is 21.8°. However, this represents a high-energy conformer, the ground state conformation being the (non-gear-meshed) all-axial form.
39. This behavior is analogous to that of the polyisopropylbenzenes. See: Kahr, B.; Biali, S. E.; Schaefer, W.; Buda, A. B., Mislow, K. J. Org. Chem. 1987, 52, 3713.
40. trans axial substituents can be arranged in anti arrangements as shown in 2 where the six isopropyl groups adopt anti arrangements.