Isolation, chemistry, and biology of pyrrolo[1,4]benzodiazepine natural products

The isolation of the antitumor antibiotic anthramycin in the 1960s prompted extensive research into pyrrolo[1,4]benzodiazepines (PBD) as potential therapeutics for the treatment of cancers. Since then, nearly 60 PBD natural products have been isolated and evaluated with regard to their biological activity. Synthetic studies and total syntheses have enabled access to PBD analogues, culminating in the development of highly potent anticancer agents. This review provides a summary of the occurrence and biological activity of PBD natural products and covers the strategies employed for their total syntheses.