Total Synthesis of (-)-Daphenylline.

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Daphniphyllum alkaloids are a class of complex natural products with unique hexacyclic structures.
• (-)-Daphenylline is a notable member of this alkaloid family, presenting significant synthetic challenges.
• Understanding the total synthesis of such molecules is crucial for exploring their potential biological activities.

Purpose of the Study:

• To achieve the first total synthesis of (-)-daphenylline.
• To develop novel synthetic strategies for constructing complex hexacyclic alkaloid frameworks.
• To provide a scalable route for accessing (-)-daphenylline for further biological evaluation.

Main Methods:

• Asymmetric Negishi coupling for initial DEF ring system construction.
• Intramolecular Friedel-Crafts reaction to complete the tricyclic core.
• Sonogashira coupling and stereocontrolled Claisen rearrangement for side chain installation.
• Stereoselective alkylation of a lactone.
• Intramolecular cycloaddition of a cyclic azomethine ylide for ABC ring system formation.

Main Results:

• Successful construction of the pentacyclic core of (-)-daphenylline.
• Stereoselective installation of key functional groups and side chains.
• Completion of the total synthesis of (-)-daphenylline, confirming its structure.
• Demonstration of a viable synthetic route to this complex natural product.

Conclusions:

• The total synthesis of (-)-daphenylline was accomplished, validating the proposed synthetic strategy.
• The developed methods offer new tools for the synthesis of structurally related alkaloids.
• This synthesis provides access to (-)-daphenylline for future pharmacological studies.