title: Tethering for selective synthesis of 2,2'-biphenols: the acetal method.
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.
authors.affiliation: 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; Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49) 721-6084-8581. kye.masters@qut.edu.
authors.forename: Kye-Simeon
authors.initials: KS
authors.lastname: Masters
authors.forename: Angela
authors.initials: A
authors.lastname: Bihlmeier
authors.forename: Wim
authors.initials: W
authors.lastname: Klopper
authors.forename: Stefan
authors.initials: S
authors.lastname: Bräse
mesh_terms: D000080:Acetals / Q000138:chemical synthesis* / Q000737:chemistry*; D019281:Dimerization; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000080:Acetals; D010636:Phenols; C038764:2,2'-biphenol
keywords: acetals; aromatic substitution; biaryls; dioxepines; tethers