Rapid construction of bisindole alkaloids caulersin and racemosin B from methyl 3-indolylpyruvate based on a biomimetic dimerization strategy

Attempts to directly construct bisindole alkaloids caulerpin and caulersin resulted in the discovery of novel synthetic approaches to a specific bisindole framework with a central troponoid core and an unexpected product-racemosin B. The developed biomimetic domino sequences were triggered by a dimerization process from a shared precursor, methyl 3-indolylpyruvate. Thus, caulersin and racemosin B could be produced in 1 and 2 step processes.