The Aspidosperma alkaloids leuconoxine, melodinine E, and mersicarpine were synthesized. The approach features a key cascade radical reaction. A 1,5-hydrogen atom transfer is followed by spontaneous 5-exo-trig cyclization to construct the central indoline architecture. Late-stage differentiation of the radical cyclization product by chemoselective oxidation allows production of either the leuconoxine/melodinine E or mersicarpine structure.
Keywords: leuconoxine; melodinine E; mersicarpine; radical reactions; total synthesis.
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