Total Synthesis of Passifetilactone D, Cryptorigidifoliol I, and Cryptorigidifoliol B Isomers Enabled by Ghosez Lactonization

A concise and efficient asymmetric total synthesis of bicyclic-THP-lactone natural products passifetilactone D and cryptorigidifoliol I and four of the stereoisomers of proposed cryptorigidifoliol B has been achieved, enabled by Maruoka/Reetz or Maruoka/Brown allylations and Ghosez lactonization. Although the required diastereomers of cryptorigidifoliol B are synthesized now, with the mismatch of data to that of the natural isolate, its actual structure could not be ascertained, indicating a need for further structure revision.