Bioinspired total synthesis of (−)-gymnothelignan L

The first asymmetric total synthesis of gymnothelignan L has been accomplished in 14 steps with 11.2% overall yield. The synthetic approach features an anti Evans aldol reaction, a diastereoselective methylation, a Suzuki-Miyaura coupling and a bioinspired desymmetric transannular Friedel-Crafts reaction. Notably, the synthesis further demonstrated the biogenetic pathway that dibenzocyclooctene-type lignans are generated from eupomatilone-type lignans.