Catalytic Asymmetric Total Syntheses of (+)- and (−)-ar-Elvirol Methyl Ether

Abstract A catalytic asymmetric approach to either of the enantiomers of naturally occurring sesquiterpenes, i.e., (+)-ar-elvirol (1a) and (−)-ar-elvirol (ent-1a), has been achieved via a reductive transposition of a tertiary alcohol following a key allylic diazene arrangement (ADR) from an advanced enantioenriched tertiary allyl alcohol. The ADR proceeds via the reductive transposition of olefin under the Mitsunobu reaction with o-nitro benzene sulfonyl hydrazide followed by the decomposition of the sulfonyl hydrazide adduct. This approach has been utilized for the total syntheses of bisabolene sesquiterpenoids, (+)-ar-elvirol methyl ether (1b) and (−)-ar-elvirol methyl ether (ent-1b).