Total Synthesis of (-)-Melanthioidine by Copper-Mediated Cyclodimerization

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Phenethyltetrahydroisoquinoline alkaloids are a significant class of natural products.
• (-)-Melanthiodine is a dimeric macrocyclic alkaloid with potential biological activity.
• Efficient synthetic routes are crucial for studying and utilizing complex natural products.

Purpose of the Study:

• To report an efficient asymmetric total synthesis of (-)-melanthiodine.
• To establish a scalable and stereoselective method for constructing the dimeric macrocyclic structure.
• To provide access to enantioenriched phenethyltetrahydroisoquinoline subunits.

Main Methods:

• Noyori asymmetric transfer hydrogenation for enantioselective synthesis of the monomeric subunit.
• Copper-mediated cyclodimerization for macrocyclization and diaryl ether bond formation.
• Multi-step organic synthesis involving key C-O bond formations.

Main Results:

• Successful asymmetric total synthesis of (-)-melanthiodine achieved.
• High enantiomeric excess obtained for the phenethyltetrahydroisoquinoline monomer.
• Efficient formation of the dimeric macrocyclic diaryl ether structure.

Conclusions:

• The developed synthetic strategy is efficient and stereoselective.
• This synthesis provides a valuable route to (-)-melanthiodine and related analogs.
• The methodology can be applied to the synthesis of other complex macrocyclic alkaloids.