Stepwise, Protecting Group Free Synthesis of [4]Rotaxanes
Stepwise, Protecting Group Free Synthesis of [4]Rotaxanes
Despite significant advances in the last three decades towards high yielding syntheses of rotaxanes, the preparation of systems constructed from more than two components remains a challenge. Herein we build upon our previous report of an active template copper-catalyzed azide-alkyne cycloaddition (CuAAC) rotaxane synthesis with a diyne in which, following the formation of the first mechanical bond, the steric bulk of the macrocycle tempers the reactivity of the second alkyne unit. We have now extended this approach to the use of 1,3,5-triethynylbenzene in order to successively prepare [2]-, [3]- and [4]rotaxanes without the need for protecting group chemistry. Whilst the first two iterations proceeded in good yield, the steric shielding that affords this selectivity also significantly reduces the efficacy of the active template (AT)-CuAAC reaction of the third alkyne towards the preparation of [4]rotaxanes, resulting in severely diminished yields.
rotaxane; mechanically interlocked; copper-catalyzed azide-alkyne cycloaddition; CuAAC; active template
Lewis, James
42b46a03-a7ca-4d3a-96e5-a5c962fc9573
Winn, Joby
5f38d7c8-e656-4191-85c5-1323197b0bdd
Goldup, Stephen
0a93eedd-98bb-42c1-a963-e2815665e937
9 January 2017
Lewis, James
42b46a03-a7ca-4d3a-96e5-a5c962fc9573
Winn, Joby
5f38d7c8-e656-4191-85c5-1323197b0bdd
Goldup, Stephen
0a93eedd-98bb-42c1-a963-e2815665e937
Lewis, James, Winn, Joby and Goldup, Stephen
(2017)
Stepwise, Protecting Group Free Synthesis of [4]Rotaxanes.
Molecules, 22(1) (89).
(doi:10.3390/molecules22010089).
Abstract
Despite significant advances in the last three decades towards high yielding syntheses of rotaxanes, the preparation of systems constructed from more than two components remains a challenge. Herein we build upon our previous report of an active template copper-catalyzed azide-alkyne cycloaddition (CuAAC) rotaxane synthesis with a diyne in which, following the formation of the first mechanical bond, the steric bulk of the macrocycle tempers the reactivity of the second alkyne unit. We have now extended this approach to the use of 1,3,5-triethynylbenzene in order to successively prepare [2]-, [3]- and [4]rotaxanes without the need for protecting group chemistry. Whilst the first two iterations proceeded in good yield, the steric shielding that affords this selectivity also significantly reduces the efficacy of the active template (AT)-CuAAC reaction of the third alkyne towards the preparation of [4]rotaxanes, resulting in severely diminished yields.
Text
Molecules 16112016
- Accepted Manuscript
Text
molecules-22-00089
- Version of Record
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Accepted/In Press date: 25 December 2016
e-pub ahead of print date: 9 January 2017
Published date: 9 January 2017
Keywords:
rotaxane; mechanically interlocked; copper-catalyzed azide-alkyne cycloaddition; CuAAC; active template
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Local EPrints ID: 406512
URI: http://eprints.soton.ac.uk/id/eprint/406512
PURE UUID: fb958bd5-888b-49ff-8dbb-692c14b3f5e0
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Date deposited: 18 Mar 2017 02:21
Last modified: 15 Mar 2024 12:40
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Author:
James Lewis
Author:
Joby Winn
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