Organolead-mediated arylation of allyl β-ketoesters: a selective synthesis of isoflavanones and isoflavones

Arylation of A- ring substituted and unsubstituted 3-allyloxycarbonylchroman-4-ones with aryllead (IV) triacetates followed by selective catalytic deallyloxycarbonylation affords isoflavanones or isoflavones in high overall yields. The highest yield in the arylation step was observed in the reaction of 5,7-dimethoxychroman-4-one with the more hindered 2,4,6-trimethoxyphenyllead triacetate.