Concise total synthesis of (±)-aspidospermidine.

Area of Science:

• Organic Chemistry
• Natural Product Synthesis
• Medicinal Chemistry

Background:

• Aspidosperma alkaloids are a significant class of indole alkaloids with diverse biological activities.
• Efficient synthetic routes to complex alkaloids like (±)-Aspidospermidine are crucial for further research and development.

Purpose of the Study:

• To develop a concise and efficient synthetic strategy for (±)-Aspidospermidine.
• To establish a versatile synthetic methodology applicable to other Aspidosperma alkaloids.

Main Methods:

• The synthesis commenced from commercially available 2,3-dihydro-1H-carbazol-4(9H)-one.
• A key transformation involved a one-pot sequence of carbonyl reduction, iminium ion formation, and intramolecular conjugate addition.
• The overall synthesis was completed in 10 steps.

Main Results:

• (±)-Aspidospermidine was successfully synthesized with a 20% overall yield.
• The developed one-pot reaction proved to be a pivotal step in the synthetic route.
• The methodology demonstrated potential for broader application within the Aspidosperma alkaloid family.

Conclusions:

• A novel and efficient 10-step synthesis of (±)-Aspidospermidine has been achieved.
• The key one-pot reaction offers a powerful tool for constructing the Aspidosperma alkaloid core structure.
• This synthetic strategy paves the way for accessing other related natural products and their analogs.