An efficient asymmetric synthesis of furofuran lignans: (+)-sesamin and (−)-sesamin

An efficient synthesis of (+)-sesamin 1a and (−)-sesamin 1b is described. The key reactions include highly stereoselective aldol condensation of piperonal 7 with the dianion of chiral oxazolidinone 8, followed by intramolecular ring cyclization of aldol product 11 in high yield.