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

A concise total synthesis of (±)-myrioneurinol has been achieved in 14 steps. An efficient AgSbF6 /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.