Thallium in Organic Synthesis. 60. 2,6-Diaryl-3,7-dioxabicyclooctane-4,8-dione Lignans by Oxidative Dimerization of 4-Alkoxycinnamic Acids with Thallium(III) Trifluoroacetate or Cobalt(III) Trifluoride

Article abstract of DOI:10.1021/jo00328a018

Oxidation of p-alkoxycinnamic acids either with thallium(III) trifluoroacetate in TFA/CH2Cl2 or with cobalt(III) trifluoride in CH3CN, in the presence of a small amount of BF3*Et2O, results in instantaneous oxidative dimerization to give the bislactone li