Chiral Biscavitand Propellers: Synthesis, Conformations and Multiple Guest Binding

Organic Letters

Volumn 4, Issue 9, 2002, Pages 1455-1458

  Barrett, Elizabeth S ^a   Irwin, Jacob L ^a   Turner, Peter ^a   Sherburn, Michael S ^a  

^a UNIVERSITY OF SYDNEY   (Australia)

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ARTICLE;

EID: 0042877019     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol025704n     Document Type: Article

References (35)

1. (a) Cram, D. J. Science 1983, 219, 1177-1183.
2. (b) Cram, D. J.; Cram, J. M. Container Molecules and their Guests, Monographs in Supramolecular Chemistry, Vol. 4; Stoddart, J. F., Ed., Royal Society of Chemistry: Cambridge, 1994.
3. (c) Verboom, W. in Calixarenes 2001; Asfari, Z., Bohmer, V., Harrowfield, J., Vicens, J., Eds.; Kluwer: Dordrecht, 2001; pp 181-198.
4. (a) Jasat, A.; Sherman, J. C. Chem. Rev. 1999, 99, 931-967.
5. (b) Warmuth R. J. Inclusion Phenom. Mol. Recognit. Chem. 2000, 37, 1-38.
6. (c) Naumann, C.; Sherman, J. C. In Calixarenes 2001; Asfari, Z., Bohmer, V., Harrowfield, J., Vicens, J., Eds.; Kluwer: Dordrecht, 2001; pp 199-218.
7. (d) Warmuth, R. Eur. J. Org. Chem. 2001, 423-437.
8. (e) Warmuth, R.; Yoon, J. Acc. Chem. Res. 2001, 34, 95-105.
9. To the best of our knowledge, there are no reports of bisbowl molecules with connecting chains of less than three atoms.
10. (a) Larsen, M.; Jorgensen, M. J. Org. Chem. 1996, 61, 6651-6655.
11. (b) Irwin, J. L.; Sherburn, M. S. J. Org. Chem. 2000, 65, 602-605.
12. (c) Irwin, J. L.; Sherburn, M. S. J. Org. Chem. 2000, 65, 5846-5848.
13. (d) Irwin, J. L.; Sherburn, M. S. Org. Lett. 2001, 3, 225-227.
14. (e) Barrett, E. S.; Irwin, J. L.; Turner, P.; Sherburn, M. S. J. Org. Chem. 2001, 66, 8227-8229.
15. 4d were unsuccessful, the bowl-appended monoesters being recovered unchanged. Cavitand monoesters were similarly unreactive towards 2,6-dimethoxy-l-lithiobenzene.
16. Taking the average planes of the bowls as those described by the positions of the eight acetal oxygens, the angle between the two cavitand moieties is 87.5°.
17. The propeller structure for diaryl ketones in the solid state is wellknown: Rapoport, Z.; Biali, S. E.; Kaftory, M. J. Am. Chem. Soc. 1990, 112, 7742-7748.
18. Caviplexes with dichloromethane residing inside the bowl have been witnessed previously, (a) Cram, D. J.; Karbach, S.; Kim, H.-E.; Knobler, C. B.; Maverick, E. F.; Ericson, J. L.l Helgeson, R. C. J. Am. Chem. Soc. 1988, 110, 2279-2237.
19. (b) Beer, P. D.; Tite, E. L.; Drew, M. G. B.; Ibbotson, A. J. Chem. Soc., Dalton Trans. 1990, 2543-2550.
20. (c) Berridge, T. E.; Chen, H.; Hamor, T. A.; Jones, C. J. Polyhedron 1997, 16, 2329-2333.
21. (d) Sebo, L.; Diederich, F.; Gramlich, V. Helv. Chim. Acta. 2000, 83, 93-113.
22. Kawaguchi, T.; Tanaka, K.; Takeuchi, T.; Watanabe, T. Bull. Chem. Soc. Jpn. 1973, 46, 62-66.
23. Jackman, L. M.; Sternhell, S. Applications of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry, 2nd ed.; Pergamon Press: Braunschweig, 1969; Chapter 5-2, pp 368-379.
24. Intrinsic nonequivalence in this system arises as a result of the conformationally rigid nature of each cavitand bowl: the two faces of each aromatic residue contained therein is thus differentiated.
25. See Supporting Information for full details.
26. The compound crystallizes from solution below this temperature, precluding further study.
27. Grilli, S.; Lunazzi, L.; Mazzanti, A.; Casarini, D.; Femoni, C. J. Org. Chem. 2001, 66, 488-495.
28. For studies with bis(tricarbonylchromium) complexes of diaryl ketones, see: Weissensteiner, W.; Scharf, J.; Schlögl, J. Org. Chem. 1987, 52, 1210-1215.
29. Both in,out- and out,out-conformers have close contacts between the bowls involving acetal bridge protons adjacent to the benzophenone moiety, and in the latter case this strain is severe.
30. 12 Models of 2c undergo a conrotatory two-ring flip pathway more readily. For a discussion of molecular rotors, see: Balzani, V.; Cedi, A.; Raymo, F. M.; Stoddart, J. F. Angew. Chem., Int. Ed. 2000, 39, 3348-3391.
31. Computational and experimental data point to a similar preferred twisted conformation in diaryl methanes: Strassner, T. Can. J. Chem. 1997.
32. Head-head, methylene-linked biscalix[4]arenes: (a) Böhmer, V.; Goldmann, H.; Vogt, W.; Vicens, J.; Asfari, Z. Tetrahedron Lett. 1989, 30, 1391-1394,
33. (b) Araki, K.; Hisaichi, K.; Kanai, T.; Shinkai, S. Chem. Lett. 1995, 569-570.
34. (c) Arduini, A.; Pochini, A.; Secchi, A. Eur. J. Org. Chem. 2000, 2325-2334.
35. The closed shell (hemicarcerand-like) structure of one-atom-linked biscalix[41arenes and bisbowls requires a conformation about the two-bond linker that corresponds to the transition state for enantiomerization (ii): formula represented