The Chemistry of the Canthin-4-ones

Background: The canthin-4-ones are a small, yet underexplored class of natural products from Apocynaceae plants. Efficient synthetic approaches are required for exploring this class of natural products for drug discovery. Objective: In this review, the synthetic approaches towards these alkaloids, as well as synthetic analogues are summarized comprehensively. Further, the applications of canthin-4-ones as building blocks for the synthesis of alkaloids and other polycyclic compounds of pharmaceutical interest are demonstrated. Conclusion: Meanwhile, efficient and flexible approaches to the canthin-4-one scaffold are available which should foster in-depth investigation of this chemotype for drug development.