Total Synthesis of the Cytotoxic Marine Triterpenoid Isodehydrothyrsiferol Reveals Partial Enantiodivergency in the Thyrsiferol Family of Natural Products

Recently, the phenomenon of enantiodivergence was uncovered as a new phenomenon in the biosynthesis of natural products. In nature, chiral natural products are usually produced in optically active form, but both enantiomers sometimes arise in different genera and/or species or in a single species. Here we show through enantioselective total synthesis that the natural product isodehydrothyrsiferol shows partial enantiodivergency in that six of the nine or ten asymmetric centers are enantiomeric to those of other members of the marine squalene‐derived triterpenoid thyrsiferol family. In addition, isodehydrothyrsiferol and dehydrothyrsiferol, which show partial enantiodivergency, were isolated from the same producer, the red alga Laurencia viridis. These results demonstrate that partial enantiodivergence can develop even between natural products originating from a single species. See both sides: Enantioselective total synthesis of the cytotoxic marine triterpenoid isodehydrothyrsiferol revealed partial enantiodivergence in that the ABC ring system is enantiomeric to that of the other members of this natural product family. Furthermore, this unprecedented partial enantiodivergence is observed between dehydrothyrsiferol and isodehydrothyrsiferol, which originate from a single species, the red alga Laurencia viridis.