Application of aryllead(IV) derivatives to the preparation of 3-aryl-4-hydroxy-1-benzopyran-2-ones

Aryllead triacetates are chemoselective and regioseiective reagents for the preparation of 3-aryl-4-hydroxy-1-benzopyran-2-ones in good to excellent yields by C-3 arylation of the preformed 4-hydroxy-1-benzopyran-2-one ring. This approach was applied to the high-yielding synthesis of naturally occurring examples. A radical mechanism was discounted and the mechanism proposed involves the ligand coupling of an intermediate possessing an enolate-to-lead bond to afford arylated products.