Synthesis of (+)-aptosimon, a 4-oxofurofuran lignan, by erythro selective aldol condensation and stereoconvergent cyclization as the key reactions.

The 4-oxofurofuran lignan, (+)-aptosimon (1), was synthesized from gamma-butyrolactone (9). To construct the two benzylic chiral center of (+)-aptosimon (1), highly erythro selective aldol condensation and stereoconvergent SN1 intramolecular cyclization were used as the key reactions.