Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron

Synthetic Entry to the 2-Azatricyclo[4.3.2.04,9]undecane Ring System via Tropone

“…These two reactions were conveniently streamlined by removing the excess allylamine from this first step via rotary evaporation followed by dissolving the residue in ethanol and sonicating in the presence of excess Boc 2 O and NaHCO 3 . The diene was then disengaged from the iron tricarbonyl fragment upon treatment with cerium ammonium nitrate (CAN) at 0 °C. , The 1 H NMR spectrum of the product of this reaction showed only two resonances corresponding to vinylic protons and no sign of the expected dienone or terminal alkene ( 13a ), suggesting that the intramolecular Diels–Alder reaction had occurred spontaneously following demetallation to give the tricyclic compound 14a directly. This conclusion was ultimately confirmed by X-ray crystallography (CCDC No.…”

“…In a first step toward realizing our goal of synthesizing diverse bridged azapolycycles from 5 , we recently reported a method for appending functionalized amines to the tropone nucleus via direct aza-Michael addition of unhindered aliphatic amines to 5 . Herein, we report the utilization of the aza-Michael adduct of allylamine, which we reported previously, in the construction of a novel bridged azapolycycle ( 11 ) via demetallation of the complex followed by an intramolecular Diels–Alder reaction of the unmasked dienone (Scheme ).…”