Total synthesis of (+)-cassaine utilizing an anionic polycyclization strategy.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Natural Product Synthesis

Background:

• (+)-Cassaine is a complex natural product with significant biological interest.
• Stereoselective synthesis is crucial for accessing complex molecules like (+)-cassaine.
• Anionic polycyclization offers a powerful strategy for constructing polycyclic frameworks.

Purpose of the Study:

• To achieve a stereoselective total synthesis of (+)-cassaine.
• To develop and apply an anionic polycyclization methodology for natural product synthesis.
• To utilize a readily available chiral starting material for stereochemical control.

Main Methods:

• Stereoselective total synthesis of (+)-cassaine.
• Anionic polycyclization reaction between a substituted cyclohexenone and a sulfinyl enone.
• Functional group manipulations for final product formation.

Main Results:

• Successful stereoselective total synthesis of (+)-cassaine (1).
• Anionic polycyclization yielded a versatile tricycle (2) with the desired stereochemistry.
• (+)-Carvone (5) served as the chiral pool precursor, dictating the stereochemistry.

Conclusions:

• The described anionic polycyclization methodology is effective for the stereoselective synthesis of (+)-cassaine.
• This approach provides a viable route to (+)-cassaine and related natural products.
• The use of (+)-carvone highlights the utility of chiral pool synthesis.