Total syntheses of murrayamine E, I, and K

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Natural Product Synthesis

Background:

• Murrayamine alkaloids are a class of natural products with potential biological activities.
• Efficient synthetic methods are crucial for accessing these complex molecules for further study.

Purpose of the Study:

• To develop efficient synthetic routes to specific murrayamine alkaloids.
• To achieve the first total syntheses of murrayamine E, I, and K.
• To explore key catalytic steps in the synthesis.

Main Methods:

• Palladium-catalyzed cross-coupling reactions for carbazole framework construction.
• Annulation reactions for pyran ring formation, utilizing phenylboronic acid or Lewis acid catalysis.

Main Results:

• Efficient synthetic routes were established for murrayamine A (mukoenine C), O-methylmurrayamine A, mahanine, O-methylmahanine, and murrayamine D.
• The first total syntheses of murrayamine E, I, and K were successfully accomplished.
• Key catalytic methodologies were optimized for carbazole and pyran ring formation.

Conclusions:

• The developed synthetic strategies provide access to a range of valuable murrayamine alkaloids.
• The study highlights the utility of palladium catalysis and novel annulation methods in natural product synthesis.