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

Dedication

This paper is dedicated respectfully to Prof. S. Chandrasekaran, Department of Organic Chemistry, IISc Bangalore, India, on the occasion of his 80th birthday.

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).

Keywords

Allylic diazene rearrangement (ADR) - Asymmetric conjugate addition - Aromatic bisabolanes - E-Ethyl crotonate - Boronic acid - (+)-ar-Elvirol (1a) - (+)-ar-Elvirol methyl ether (1b)

Publication History

Received: 03 June 2025

Accepted after revision: 03 August 2025

Accepted Manuscript online:
03 August 2025

Article published online:
01 September 2025

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