Total synthesis of phorboxazole B

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Synthetic Chemistry

Background:

• Phorboxazole B is a potent marine natural product with significant antitumor activity.
• The complex structure of phorboxazole B presents a considerable challenge for total synthesis.
• Efficient synthetic routes are crucial for enabling further biological evaluation and potential therapeutic development.

Purpose of the Study:

• To develop a highly efficient and convergent total synthesis of phorboxazole B.
• To establish key stereocenters and construct the macrolide ring system.
• To explore novel synthetic methodologies for complex molecule construction.

Main Methods:

• Substrate-controlled hydrogenation for cis-tetrahydropyrane construction.
• Iterative crotyl additions for building substituted segments.
• Mercury(II) acetate/iodine-induced cyclization for tetrahydropyrane formation.
• Mukaiyama aldol reaction with 1,3-asymmetric induction.
• Still-Gennari olefination for macrolide ring closure.

Main Results:

• A highly convergent and efficient total synthesis of phorboxazole B was successfully achieved.
• Key structural features, including the cis-tetrahydropyrane unit and alternating hydroxyl/methyl substituents, were constructed with high fidelity.
• The synthetic strategy effectively established the required stereogenic centers at C9 and C3.
• The macrolide ring was successfully formed, completing the synthesis of phorboxazole B.

Conclusions:

• The developed synthetic strategy provides a robust and efficient route to phorboxazole B.
• This synthesis validates the utility of the employed methodologies for constructing complex natural products.
• The efficient synthesis facilitates further investigation into the biological activity and therapeutic potential of phorboxazole B.