Total Synthesis of (−)-8-Deoxyserratinine via an Efficient Helquist Annulation and Double N-Alkylation Reaction

The first enantioselective total synthesis of (−)-8-deoxyserratinine has been achieved in 15 steps from enone 4 with 7% overall yield. The key features include a highly efficient Helquist annulation to furnish the cis-fused 6/5 bicycle, facile construction of the aza nine-membered ring system employing double N-alkylation strategy, as well as asymmetric Shi epoxidation, delivering the desired β-epoxide stereospecifically.