A catenane that is topologically achiral despite being composed of oriented rings
A catenane that is topologically achiral despite being composed of oriented rings
Catenanes—molecules comprising two interlocking rings held together like links in a chain—are topologically non-trivial: a catenane is a topological isomer of its separated rings, but the rings cannot be disconnected without bond scission. Catenanes can exist as topological enantiomers if both rings have directionality conferred by a defined atom sequence, but this has led to the assumption that the stereochemistry of chiral catenanes composed of oriented rings is inherently topological in nature. Here we show that this assumption is incorrect by synthesizing an example that contains the same fundamental stereogenic unit but whose stereochemistry is Euclidean. One ring in this chiral catenane is oriented by the geometry of an exocyclic double rather than determined by atom sequence within the ring. Isomerization of the exocyclic double bond results in racemization of the catenane, confirming that the stereochemistry is not topological in nature. Thus, we can unite the stereochemistry of catenanes with that of their topologically trivial cousins, the rotaxanes, enabling a more unified approach to their discussion.
781-786
Pairault, Noel
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Rizzi, Federica
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Lozano, David
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Jamieson, Ellen M. G.
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Tizzard, Graham J.
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Goldup, Stephen M.
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June 2023
Pairault, Noel
e0777b58-ccb8-41bf-84e4-7ab4ad203327
Rizzi, Federica
f05be5f8-7711-4796-9cd3-9fa5b238ea3e
Lozano, David
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Jamieson, Ellen M. G.
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Tizzard, Graham J.
8474c0fa-40df-43a6-a662-7f3c4722dbf2
Goldup, Stephen M.
0a93eedd-98bb-42c1-a963-e2815665e937
Pairault, Noel, Rizzi, Federica, Lozano, David, Jamieson, Ellen M. G., Tizzard, Graham J. and Goldup, Stephen M.
(2023)
A catenane that is topologically achiral despite being composed of oriented rings.
Nature Chemistry, 15 (6), .
(doi:10.1038/s41557-023-01194-1).
Abstract
Catenanes—molecules comprising two interlocking rings held together like links in a chain—are topologically non-trivial: a catenane is a topological isomer of its separated rings, but the rings cannot be disconnected without bond scission. Catenanes can exist as topological enantiomers if both rings have directionality conferred by a defined atom sequence, but this has led to the assumption that the stereochemistry of chiral catenanes composed of oriented rings is inherently topological in nature. Here we show that this assumption is incorrect by synthesizing an example that contains the same fundamental stereogenic unit but whose stereochemistry is Euclidean. One ring in this chiral catenane is oriented by the geometry of an exocyclic double rather than determined by atom sequence within the ring. Isomerization of the exocyclic double bond results in racemization of the catenane, confirming that the stereochemistry is not topological in nature. Thus, we can unite the stereochemistry of catenanes with that of their topologically trivial cousins, the rotaxanes, enabling a more unified approach to their discussion.
Text
rvsd1 commented MS NCHEM-22091835-T (figure 2 corrected)
- Accepted Manuscript
More information
Accepted/In Press date: 28 March 2023
Published date: June 2023
Additional Information:
Funding Information:
S.M.G thanks the European Research Council (Consolidator Grant, agreement no. 724987) and the Royal Society for a Research Fellowship (RSWF\FT\180010). E.M.G.J. thanks the EPSRC and University of Southampton for a Doctoral Prize Fellowship.
Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Nature Limited.
Identifiers
Local EPrints ID: 477475
URI: http://eprints.soton.ac.uk/id/eprint/477475
ISSN: 1755-4330
PURE UUID: eff40140-451b-407b-9028-5bca2c201962
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Date deposited: 06 Jun 2023 17:15
Last modified: 17 Mar 2024 02:53
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Author:
Federica Rizzi
Author:
David Lozano
Author:
Ellen M. G. Jamieson
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