Enantioselective Total Syntheses of Leuconolam–Leuconoxine–Mersicarpine Group Monoterpene Indole Alkaloids

A unified strategy allowing enantioselective total syntheses of (−)-mersicarpine, (−)-scholarisine G, (+)-melodinine E, (−)-leuconoxine, and (−)-leuconolam from a common cyclohexenone derivative was reported. The Suzuki−Miyaura reaction was used to couple two simple fragments incorporating the key elements for total synthesis, and unprecedented oxidation/reduction/cyclization processes were developed that converted the substituted cyclohexenone to either a mersicarpine or leuconoxine skeleton. In a reverse biomimetic synthesis fashion, (+)-melodinine E was converted to (−)-leuconolam under acidic conditions.