Radical carboxyarylation approach to lignans. Total synthesis of (-)-arctigenin, (-)-matairesinol, and related natural products.

[reaction: see text] Total syntheses of seven biologically important lignan natural products, including (-)-arctigenin, (-)-matairesinol, and (-)-alpha-conidendrin, by way of a highly stereoselective domino radical sequence is presented. The reported stereochemistry of the natural product 7-hydroxyarctigenin is shown to be erroneous; a diastereoisomeric structure is assigned to the natural product.