Intramolecular versus intermolecular oxidative couplings of ester tethered di-aryl ethers

Authors

Stephen R. Taylor, University of Wollongong
Alison T. Ung, University of WollongongFollow
Stephen G. Pyne, University of WollongongFollow
Brian W. Skelton, University of Western Australia
Allan H. White, University of Western Australia

RIS ID

21131

Publication Details

Taylor, S. R., Ung, A. T., Pyne, S. G., Skelton, B. W. & White, A. H. (2007). Intramolecular versus intermolecular oxidative couplings of ester tethered di-aryl ethers. Tetrahedron, (63), 11377-11385.

Abstract

The oxidative cyclization of 3,4-dimethoxyphenyl 3,4-dimethoxyphenylacetate, through intramolecular biphenyl bond formation, was successful and gave the target seven-membered lactone in good yield (85–86%). All other ester substrates gave biphenyl products or their further oxidized products via intermolecular coupling of their radical cation intermediate with the neutral substrate. It appears that matching of the oxidation potentials and nucleophilicity of the two phenyl rings, the positioning of the ring substituents and the ease of E to Z isomerization about the ester C–O bond are important factors contributing to these product outcomes.