A Concise Biogenetically Inspired Formal Synthesis of Camptothecin

A concise biogenetically inspired formal synthesis of camptothecin without use of protecting groups has been developed starting from tryptamine and easily prepared ethyl glutaconaldehyde salt. The synthesis features the key Pictet-Spengler reaction, efficient intramolecular oxa-Diels-Alder reaction to construct heptacyclic monoterpenoid indole alkaloid intermediate, as well as the following Winterfeldt biomimetic oxidation to form quinolinone moiety from indole skeleton.

Automated summary

A concise biogenetically inspired formal synthesis of camptothecin has been developed, utilizing key reactions such as Pictet-Spengler reaction, intramolecular oxa-Diels-Alder reaction, and Winterfeldt biomimetic oxidation without the use of protecting groups.