4
950
J . Org. Chem. 2001, 66, 4950-4953
Tem p la te Effects in th e Self-Assem bly of a
Sch em e 1
[
2]Rota xa n e a n d a [2]P seu d or ota xa n e w ith
th e Sa m e Bin d in g Sites in th e Lin ea r
Com p on en t
Giancarlo Doddi,*,† Gianfranco Ercolani,*,‡
†
,†
Silvia Franconeri, and Paolo Mencarelli*
Dipartimento di Chimica e Centro CNR di Studio sui
Meccanismi di Reazione, Universit a` di Roma La Sapienza,
P.le Aldo Moro, 2, 00185 Roma, Italy, and Dipartimento di
Scienze e Tecnologie Chimiche, Universit a` di Roma Tor
Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy
Received April 13, 2001
In tr od u ction
In recent years self-assembly has become one of the
preeminent themes of supramolecular chemistry, allow-
ing the syntheses of a great variety of complex molecular
systems.1 The efficient preparation of rotaxanes, in
particular, has enormously benefited from template-
2
,3
directed approaches. Rotaxanes are molecules compris-
ing one or more macrocycles threaded by a linear
component bearing large stoppers at the ends to prevent
the unthreading of the cyclic component. Three ap-
proaches can be employed for the self-assembly of a
†
Universit a` di Roma La Sapienza.
Universit a` di Roma Tor Vergata.
‡
(
1) For general reviews on self-assembly, see: (a) Lehn, J .-M.
Supramolecular Chemistry: Concepts and Perspectives; VCH: Wein-
heim, 1995. (b) Lawrence, D. S.; J iang, T.; Levett, M. Chem. Rev. 1995,
9
5, 2229-2260. (c) Philp, D.; Stoddart, J . F. Angew. Chem., Int. Ed.
Engl. 1996, 35, 1154-1196. (d) Comprehensive Supramolecular Chem-
istry, Vol. 9; Atwood, J . L., Davies, J . E. D., MacNicol, D. D., V o¨ gtle,
F., Sauvage, J .-P., Hosseini, M. W., Eds.; Pergamon: Oxford, 1996.
e) Zeng, F. W.; Zimmerman, S. C. Chem. Rev. 1997, 97, 1681-1712.
Conn, M. M.; Rebek, J . Chem. Rev. 1997, 97, 1647-1668. (h) Fujita,
M. Chem. Soc. Rev. 1998, 27, 417-425. (i) Leininger, S.; Olenyuk, B.;
Stang, P. J . Chem. Rev. 2000, 100, 853-908. (j) Lindoy, L. F.; Atkinson,
I. Self-Assembly in Supramolecular Systems (Monographs in Supra-
molecular Chemistry); Stoddart, J . F., Ed.; RSC: Cambridge, U.K.,
rotaxane:3b,c in the clipping approach, the cyclization of
one component is carried out in the presence of a
preformed dumbbell-shaped compound, which acts as the
template for the ring closure; in the threading, the
inclusion of an acyclic derivative inside the cavity of a
macrocycle is followed by the covalent attachment of two
stoppers to prevent the unthreading of the ring; in the
last and less common one, the slipping approach, the two
preformed components, the cyclic and the dumbbell-
shaped compounds, are forced into associating one with
the other by providing thermal energy.
Despite the numerous examples of template-directed
syntheses of rotaxanes that can be found in the literature,
no kinetic study of template effects in the formation of
rotaxanes by the clipping approach has been reported to
date, apart from a previous study dealing with the
formation of a [2]pseudorotaxane constituted by cyclobis-
2
000. (k) Molecular Self-Assembly (Structure and Bonding, Vol. 96);
Fujita, M., Ed.; Springer: Heidelberg, 2000.
2) For general reviews on template effects, see: (a) Anderson, S.;
(
Anderson, H. L.; Sanders, J . K. M. Acc. Chem. Res. 1993, 26, 469-
4
3
75. (b) Hoss, R.; V o¨ gtle, F. Angew. Chem., Int. Ed. Engl. 1994, 33,
75-384. (c) Busch, D. H.; Vance, A. L.; Kolchinski, A. G. In
Comprehensive Supramolecular Chemistry, Vol. 9; Atwood, J . L.,
Davies, J . E. D., MacNicol, D. D., V o¨ gtle, F., Sauvage, J .-P., Hosseini,
M. W., Eds.; Pergamon: Oxford, 1996; Chapter 1. (d) Gerbeleu, N. V.;
Arion, V. B.; Burgess, J . Template Synthesis of Macrocyclic Com-
pounds; Wiley-VCH: Weinheim, 1999. (e) Templated Organic Synthe-
sis; Diederich, F., Stang, P. J ., Eds.; Wiley-VCH: Weinheim, 2000.
(
3) For reviews on template-directed syntheses of rotaxanes, besides
ref 1c, see: (a) Amabilino, D. B.; Stoddart, J . F. Chem. Rev. 1995, 95,
725-2828. (b) Belohradsky, M.; Raymo, F. M.; Stoddart, J . F. Collect.
2
Czech. Chem. Commun. 1996, 61, 1-43. (c) Amabilino, D. B.; Raymo,
F. M.; Stoddart, J . F. in Comprehensive Supramolecular Chemistry,
Vol. 9; Atwood, J . L., Davies, J . E. D., MacNicol, D. D., V o¨ gtle, F.,
Sauvage, J .-P., Hosseini, M. W., Eds.; Pergamon: Oxford, 1996;
Chapter 3. (d) Gibson, H. W. In Large Ring Molecules; Semlyen, J . A.,
Ed.; Wiley: New York, 1996; pp 191-262. (e) Molecular Catenanes,
Rotaxanes and Knots; Sauvage, J .-P., Dietrich-Buchecker, C. O., Eds.;
Wiley-VCH: Weinheim, 1999. (f) Bruce, J . I.; Sauvage, J .-P. Adv.
Molecular Struct. Res. 1999, 5, 153-187. (g) Blanco, M. J .; J imenez,
M. C.; Chambron, J . C.; Heitz, V.; Linke, M.; Sauvage, J . P. Chem.
Soc. Rev. 1999, 28, 293-305. (h) Gibson, H. W.; Mahan, E. J . In Cyclic
Polymers, 2nd ed.; Semlyen, J . A., Ed.; Kluwer: Dordrecht, The
Netherlands, 2000; pp 415-560.
(
paraquat-p-phenylene) and 1,4-bis[2-(2-hydroxyethoxy)-
4
ethoxy]benzene.
Several examples of template-directed syntheses of
rotaxanes are from the work of Stoddart and co-workers
(4) Capobianchi, S.; Doddi, G.; Ercolani, G.; Keyes, J . W.; Mencarelli,
P. J . Org. Chem. 1997, 62, 7015-7017.
1
0.1021/jo015684n CCC: $20.00 © 2001 American Chemical Society
Published on Web 06/19/2001