Concise Synthesis of (±)‐Myrioneurinol Enabled by Sequential [2+2] Cycloaddition/Retro‐Mannich Fragmentation/Mannich Reaction

Abstract A concise total synthesis of (±)‐myrioneurinol has been achieved in 14 steps. An efficient AgSbF 6 / t ‐BuCl‐catalyzed intramolecular [2+2] cycloaddition reaction of the alkynone‐tethered enamine was developed to prepare the highly strained cyclobutene. It was used in combination with a subsequent retro‐Mannich fragmentation/Mannich reaction to efficiently construct the tricyclic core of myrioneurinol.