Total Synthesis of Lucidumone through Convenient One-pot Preparation of the Tetracyclic Skeleton by Claisen Rearrangement and Subsequent Intramolecular Aldol Reaction.

The total synthesis of lucidumone (1), a Ganoderma meroterpenoid, was accomplished in racemic form from easily prepared 6 and 7 in 10 steps as the longest linear sequence. The synthesis was completed through one-pot preparation of the tetracyclic core skeleton by Claisen rearrangement followed by an intramolecular aldol reaction. The intramolecular aldol reaction allowed for the stereocontrolled construction of the bicyclo [2.2.2] octane skeleton fused to an indanone structure. The enantioselective total synthesis of 1 was also described via a chiral transfer strategy in the Claisen rearrangement.