Total Syntheses of (+)-Penicibilaenes A and B via Enantioselective Desymmetrization

Stereocontrolled total syntheses of (+)-penicibilaenes A and B were accomplished through three key steps: (1) Pd-catalyzed enantioselective desymmetrization to afford a pivotal chiral intermediate having an all-carbon quaternary stereogenic center, (2) ring-closing metathesis to form the bicyclo[3.3.1]nonane core, and (3) intramolecular nitrile oxide [3 + 2] cycloaddition to assemble the tricyclo[6.3.1.0^1,5]dodecane skeleton. Enantioselective desymmetrization delivered a highly functionalized cyclohexene, which provided access to (+)-penicibilaenes A and B.