Diversity-Oriented Synthetic Approaches for Furoindoline: A Review

The furo [2,3-b] indoline ring system is one of the most important structural units in various natural products. It has been known to have inherent biological activities and is utilized as a synthetic target for a number of natural compounds; therefore, this has contributed to a great demand for the growth of synthetic methods for this ring system. Most important compounds with furoindoline ring system are physovenine, madindoline A and B and makomotindoline etc. These compounds are well known to exhibit biological activity against different diseases such as glaucoma, cancer, cachexia, Castleman's disease, rheumatoid arthritis, etc. The current article focuses on various synthetic approaches for furoindoline containing compounds and essential furoindoline moiety, such as oxindole-5-O-tetrahydropyranyl ether route etc., and various other diastereo-and enantio-controlled approach in a very concise way.