Evolution of a Synthetic Strategy toward the Heptacyclic Core Framework of Nominine

)-H amination and reductive amination efforts failed due to severe steric hindrance and regioselectivity issues, triggering a critical strategic revision centered on the preinstallation of the C19 oxygen functionality to bypass late-stage functionalization barriers. This revised design enabled a concise cascade Borch reductive amination to forge the embedded azabicyclo2.2.1heptane motif. This work highlights the value of strategic functional group prepositioning in addressing the synthetic challenges of cage-like diterpenoid alkaloids.