Steric buttressing changes torquospecificity in thermal cyclobutenone rearrangements, providing new opportunities for 5H-furanone synthesis
Steric buttressing changes torquospecificity in thermal cyclobutenone rearrangements, providing new opportunities for 5H-furanone synthesis
Thermally induced rearrangements of 4-hydroxycyclobutenones are known to provide clean and reliable access to an array of useful carbocyclic and fused heterocyclic ring systems. Rarely, such reactions have been diverted to an alternative pathway leading to furanone formation. Herein, we show that these switches in the course of the rearrangement occur when a substrate bears a bulky substituent and are due to adverse steric buttressing as the transition state for electrocyclisation is approached. We also show how the reaction provides new opportunities for furanone synthesis and how bulky proton and halogen surrogates can be used to divert classical rearrangement pathways toward furanone formation. Additionally, we show that classical rearrangement pathways can be promoted by the simple expedient of alcohol protection.
cyclobutenones, rearrangement, thermolysis, flow chemistry, furanones, steric buttressing, torquoselectivity
3091-3106
Sun, Wei
bca29e03-90fc-4684-875e-61d35f1b5cba
Wilson, Dharyl C.
a64ee73e-0685-4aee-b96d-a43ec736fe33
Harrowven, David C.
bddcfab6-dbde-49df-aec2-42abbcf5d10b
July 2017
Sun, Wei
bca29e03-90fc-4684-875e-61d35f1b5cba
Wilson, Dharyl C.
a64ee73e-0685-4aee-b96d-a43ec736fe33
Harrowven, David C.
bddcfab6-dbde-49df-aec2-42abbcf5d10b
Sun, Wei, Wilson, Dharyl C. and Harrowven, David C.
(2017)
Steric buttressing changes torquospecificity in thermal cyclobutenone rearrangements, providing new opportunities for 5H-furanone synthesis.
Synthesis, 49 (14), .
(doi:10.1055/s-0036-1588850).
Abstract
Thermally induced rearrangements of 4-hydroxycyclobutenones are known to provide clean and reliable access to an array of useful carbocyclic and fused heterocyclic ring systems. Rarely, such reactions have been diverted to an alternative pathway leading to furanone formation. Herein, we show that these switches in the course of the rearrangement occur when a substrate bears a bulky substituent and are due to adverse steric buttressing as the transition state for electrocyclisation is approached. We also show how the reaction provides new opportunities for furanone synthesis and how bulky proton and halogen surrogates can be used to divert classical rearrangement pathways toward furanone formation. Additionally, we show that classical rearrangement pathways can be promoted by the simple expedient of alcohol protection.
Text
SYNTHESIS Article for Repository
- Accepted Manuscript
More information
Accepted/In Press date: 3 May 2017
e-pub ahead of print date: 13 June 2017
Published date: July 2017
Keywords:
cyclobutenones, rearrangement, thermolysis, flow chemistry, furanones, steric buttressing, torquoselectivity
Organisations:
Chemistry, Organic Chemistry: SCF, Southampton Marine & Maritime Institute
Identifiers
Local EPrints ID: 411992
URI: http://eprints.soton.ac.uk/id/eprint/411992
ISSN: 0039-7881
PURE UUID: 4a93bbbf-08bd-4be8-bd55-719425bad6fa
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Date deposited: 04 Jul 2017 16:31
Last modified: 16 Mar 2024 05:29
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Author:
Wei Sun
Author:
Dharyl C. Wilson
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