A Pauson-Khand approach to the hamigerans

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Natural Product Synthesis

Background:

• Hamigeran terpenes are a class of natural products with a complex tricyclic core.
• Previous synthetic routes have faced challenges in efficiently constructing this core structure.

Purpose of the Study:

• To develop an efficient synthetic strategy for the tricyclic core of hamigeran terpenes.
• To explore the utility of intramolecular Pauson-Khand reactions in complex molecule synthesis.

Main Methods:

• An intramolecular Pauson-Khand reaction was employed for the key cyclization step.
• A silylene protecting group was utilized to tether the olefin to the aromatic framework, reducing conformational mobility.
• Ortho lithiation and Sonogashira cross-coupling chemistry were used to construct the aryl enyne precursor from a salicylic acid derivative.

Main Results:

• The study successfully constructed the tricyclic core common to hamigeran terpenes.
• The use of a silylene protecting group was crucial for enabling effective intramolecular cyclization.
• An efficient method for preparing the aryl enyne intermediate was established.

Conclusions:

• The developed synthetic route provides an effective method for accessing the hamigeran terpene core.
• This work highlights the utility of intramolecular Pauson-Khand reactions and strategic use of protecting groups in complex organic synthesis.