A Formal Synthesis of (-)-Brasilenol

Abstract

Our efforts towards a chiral pool synthesis of (-)-brasilenol from (-)-β-pinene is reported here. Starting from relatively abundant (-)-β-pinene, the unnatural enantiomer (-)-brasilenol was targeted in 11 steps. Use of stereospecific ring-opening was employed to ensure conservation of stereocenter at the isopropyl group, while hydrogenative stereospecific isomerization of exocyclic enone to endocyclic enone was utilized for prevention of racemization of the methyl group.