Aryllead Mediated Synthesis of Isoflavanone and Isoflavone Derivatives.

TLDR: In this article, the reaction of aryl-lead triacetates with 3-(phenylthio)-chroman-4-one and 2-p -methoxyphenyl-3-phenyl-thio-chroman 4-one derivatives was carried out in chloroform in presence of pyridine.

Abstract: The reaction of aryllead (IV) triacetates with 3-(phenylthio)-chroman-4-one and 2- p -methoxyphenyl-3-(phenylthio)-chroman-4-one derivatives was carried out in chloroform in presence of pyridine to afford moderate to quantitative yields of the corresponding hindered 3-aryl-3-phenylthiochroman-4-one derivatives. Removal of the phenylthio group by oxidation with dimethyldioxirane led to the corresponding isoflavones and 2- p -methoxyphenylisoflavones, and by reduction with a large excess of nickel boride to the isoflavanones and 2-(4′-anisyl)-isoflavanones respectively. In the 2- p -methoxyphenyl series the nickel boride reduction of the compounds bearing ortho -substituted 3-aryl groups gave the chalcones which were recyclised under basic catalysis.