Total Synthesis of Flustramine C via Dimethylallyl Rearrangement

The marine natural product flustramine C from the bryozoan Flustra foliacea was synthesized in five steps and 38% yield starting from Nb-methyltryptamine. The key step is the biomimetic oxidation of the natural product deformylflustrabromine causing selective 1,2-rearrangement of the inverse prenyl group. By 1H,15N HMBC experiments, it is unambiguously shown that the reaction with t-BuOCl commences with chlorination of the side chain nitrogen. Deformylflustrabromine itself was synthesized via Danishefsky inverse prenylation. [reaction: see text].