Total synthesis of (-)-corilagin

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Carbohydrate Chemistry

Background:

• Ellagitannins are complex natural products with diverse biological activities.
• The 3,6-hexahydroxydiphenoyl (HHDP) bridge is a key structural motif in many ellagitannins.
• 1C4/B-ellagitannins, characterized by ring-flipped glucose, represent a challenging subclass.

Purpose of the Study:

• To achieve the first total synthesis of 1C4/B-ellagitannins.
• To develop novel synthetic methodologies for constructing the HHDP bridge and incorporating ring-flipped glucose.

Main Methods:

• Oxidative coupling of symmetrically protected gallates.
• Temporarily ring-opened synthetic route for the 3,6-hexahydroxydiphenoyl (HHDP) bridge construction.
• Stereoselective synthesis and manipulation of glucose derivatives.

Main Results:

• Successful total synthesis of a 1C4/B-ellagitannin.
• Demonstration of a novel oxidative coupling strategy for gallates.
• Development of an efficient route to the HHDP moiety with a ring-flipped glucose core.

Conclusions:

• The developed synthetic strategy enables access to previously inaccessible 1C4/B-ellagitannins.
• This work provides a foundation for the synthesis of other complex ellagitannins.
• The methodology opens new avenues in carbohydrate and natural product synthesis.