Biomimetic total synthesis of (-)-erinacine E

Biomimetic total synthesis of (-)-erinacine E (1) has been achieved starting from the enantiopure key intermediate, which was prepared via the convergent approach developed by us. The crucial step in this synthesis is an intramolecular aldol reaction driven by the 1,2-migration of a benzoyl group within a compound that was rationally designed to prevent the retro-aldol reaction, thereby successfully providing the strained skeleton of 1. Considering the structure of a putative biosynthetic intermediate, striatal A, the intramolecular aldol reaction driven by the C4′ acetyl group could be involved in the biosynthesis of 1. This acyl group migratory ring-closing reaction could be applied to the synthesis of other strained molecules.