Total Synthesis of (−)-Laulimalide: Pd-Catalyzed Stereospecific Ring Construction of the Substituted 3,6-Dihydro[2H]pyran Units

The potent anticancer agent (−)‐laulimalide (1) was prepared through a versatile method that should allow access to other marine natural products. Key steps included a Pd‐catalyzed 1,3 chirality transfer of an allylic alcohol. The syn‐SN2′‐like processes occur stereospecifically in either 6‐endo‐trig or 6‐exo‐trig fashion to give the desired 3,6‐dihydro[2H]pyran rings (see scheme).