Short Communication Radical annulation route to the synthesis of lignans: An account †

Due to the widespread occurrence in nature and broad range of biological activities, lignans have attracted considerable interest over the years. Although several elegant synthetic methods have been developed for their synthesis, the radical annulation route remained unexplored until 1989. In this account, the synthesis of different types of natural lignans using radical cyclization reaction with various radical sources has been presented. Most of the cyclizations are highly regio- and stereoselective.