A SYNTHESIS OF (+ -)-STEMODINONE - AN APPLICATION OF ORGANOIRON CHEMISTRY TO THE CONSTRUCTION OF STERICALLY CONGESTED QUATERNARY CARBON CENTERS/

A synthesis of racemic stemodinone is described, using -5-eta-4-methox y-1,3-dimethylcyclohexadienyl)iron( I) hexafluorophosphate (9) as an e lectrophile that is the A-ring precursor. Reaction of 9 with the tin e nolate from 4,4-(ethylenedioxy)cyclohexanecarbaldehyde proceeded with excellent regioselectivity and high yield to generate an intermediate representing the A and C rings of the target molecule, The B ring was constructed by introducing a two-carbon electrophilic group onto the A ring, followed by ring closure using an intramolecular enolate alkyla tion. installation of the D ring and manipulation to give the final pr oduct followed transformations precedented with this series of compoun ds.