Total synthesis of (±)-psychotrimine

A new process for the union of anilines with tryptamine derivatives has been developed, furnishing C-3 quaternized pyrroloindoline architectures. This chemoselective coupling of a tryptamine with 1.2 equiv of 2-iodoaniline proceeds efficiently on a gram-scale using only the simple reagents N-iodosuccinimide and triethylamine. Using this new reaction, the complex natural product psychotrimine has been fashioned with a rare level of efficiency and practicality. From a readily available bromotryptamine, only four steps (41-45% overall isolated yield) are necessary to procure gram quantities of the natural product. Functional group manipulations, protecting group chemistry, and unnecessary redox fluctuations have been minimized.