Access to the pactamycin core via an epoxide opening cascade

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Medicinal Chemistry

Background:

• Pactamycin is a complex natural product with significant biological activity.
• Efficient synthesis of pactamycin's core structure is crucial for further research and development.
• Establishing multiple contiguous stereocenters remains a challenge in organic synthesis.

Purpose of the Study:

• To develop a stereocontrolled synthetic strategy for the core structure of pactamycin.
• To establish five contiguous stereocenters in a highly efficient manner.
• To provide a streamlined route to a key pharmaceutical intermediate.

Main Methods:

• A novel synthetic sequence was designed leveraging a Lewis acid-mediated epoxide opening cascade.
• Stereochemical control was achieved through strategic manipulation of epoxide intermediates.
• The synthesis was optimized to a concise 11-step process.

Main Results:

• Successfully established five contiguous stereocenters on the pactamycin core.
• The C4-C5 diol relative configuration was precisely set.
• Configuration at C7 was inverted as intended.
• The oxygenated core of pactamycin was obtained in 11 steps.

Conclusions:

• The developed synthetic strategy offers an efficient and stereocontrolled method for accessing the pactamycin core.
• This approach simplifies the synthesis of a complex natural product, facilitating further biological investigation.
• The Lewis acid-mediated epoxide cascade is a powerful tool for constructing densely functionalized molecules.