Tethering for Selective Synthesis of 2,2′‐Biphenols: The Acetal Method |
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| Authors: | Dr. Kye‐Simeon Masters Dr. Angela Bihlmeier Prof. Dr. Wim Klopper Prof. Dr. Stefan Bräse |
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| Affiliation: | 1. School of Chemistry, Physics and Mechanical Engineering, Faculty of Science and Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland, 4001 (Australia), Fax: (+61)?7‐3138‐4207;2. Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz‐Haber‐Weg 6, 76131 Karlsruhe (Germany), Fax: (+49)?721‐6084‐8581;3. Theoretical Chemistry Group, Institute of Physical Chemistry (IPC), Karlsruhe Institute of Technology (KIT), Fritz‐Haber‐Weg 2, 76131 Karlsruhe (Germany);4. Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Eggenstein‐Leopoldshafen (Germany) |
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| Abstract: | 2,2'‐Biphenols are a large and diverse group of compounds with exceptional properties both as ligands and bioactive agents. Traditional methods for their synthesis by oxidative dimerisation are often problematic and lead to mixtures of ortho‐ and para‐connected regioisomers. To compound these issues, an intermolecular dimerisation strategy is often inappropriate for the synthesis of heterodimers. The ‘acetal method’ provides a solution for these problems: stepwise tethering of two monomeric phenols enables heterodimer synthesis, enforces ortho regioselectivity and allows relatively facile and selective intramolecular reactions to take place. The resulting dibenzo[1,3]dioxepines have been analysed by quantum chemical calculations to obtain information about the activation barrier for ring flip between the enantiomers. Hydrolytic removal of the dioxepine acetal unit revealed the 2,2′‐biphenol target. |
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| Keywords: | acetals aromatic substitution biaryls dioxepines tethers |
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