First total synthesis of (+)-indicanone

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Wikstroemia indica is a plant source of bioactive compounds.
• Sesquiterpenes, like guaianes, often exhibit significant biological activities.
• The structure and stereochemistry of (+)-indicanone were previously not fully elucidated through synthesis.

Purpose of the Study:

• To achieve the first total synthesis of (+)-indicanone.
• To confirm the complete structure and absolute stereochemistry of (+)-indicanone.
• To develop a novel synthetic route applicable to related natural products.

Main Methods:

• Utilized a rhodium(I)-catalyzed Pauson-Khand-type reaction.
• Employed an allenyne derivative precursor.
• The precursor was synthesized from readily available (+)-limonene.

Main Results:

• Successfully synthesized (+)-indicanone, a guaiane-type sesquiterpene.
• The synthetic route unambiguously confirmed the proposed structure.
• Absolute stereochemistry of (+)-indicanone was definitively established.

Conclusions:

• The first total synthesis of (+)-indicanone was accomplished.
• The rhodium(I)-catalyzed reaction proved effective for constructing the guaiane skeleton.
• This work provides a foundation for further exploration of related sesquiterpenes.