# Toward the Total Synthesis of Sesquiterpene via an Annulative and Oxidative Approach

## TL;DR

This paper describes a new synthetic approach to produce the natural compound jungianol, focusing on overcoming challenges in forming specific indane structures.

## Contribution

A novel annulative and oxidative strategy is proposed for the total synthesis of (±)-jungianol, utilizing an iodine(III) reagent for ring contraction.

## Key findings

- A ring contraction reaction using an iodine(III) reagent was successfully used to form trans-1,3-substituted indanes.
- The synthesis of (±)-jungianol is now one step away from completion using the developed trans-indane intermediate.
- Key transformations like Wittig reactions, hydrogenation, and acetylation were successfully integrated into the synthetic pathway.

## Abstract

The phenolic sesquiterpene (±)-jungianol, originally
isolated
from Jungia malvifolia (family Asteraceae), has previously been targeted through various
synthetic approaches. However, none of these methods have successfully
produced (±)-jungianol as the major product, largely due to difficulties
in synthesizing trans-1,3-substituted indane frameworks.
Herein, we present an annulative strategy for the total synthesis
of (±)-jungianol, emphasizing several key transformations, including
olefination via Wittig and Grignard reactions, hydrogenation, iodination,
cross-coupling reactions, oxidation, acetylation, and hydrogenolysis
of the acetylated product. Most notably, this study explores the use
of a ring contraction reaction, particularly for the formation of trans-1,3-substituted indanes, structural motifs essential
to (±)-jungianol via an environmentally friendly iodine­(III)
reagent. Efforts are underway to synthesize the targeted natural product,
which is just one step away from our synthesized trans-indane intermediate.