Synthetic Entry to the 2‑Azatricyclo[,9]undecane Ring System via Tropone

A synthesis of the 2-azatricyclo­[,9]­undecane ring systema hitherto unreported bridged azatricyclic ring systembeginning from tricarbonyl­(tropone)iron and allylamine was accomplished in three steps: (1) aza-Michael addition of allylamine to tricarbonyl­(tropone)­iron; (2) Boc-protection of the resulting secondary amine; and (3) oxidative demetallation leading to a spontaneous intramolecular Diels–Alder reaction. The effect of a variety of parameters on the intramolecular Diels–Alder reaction was investigated, including diene and dienophile substitution patterns and dienophile tether length.