A synthesis of (±)-stemodinone: An application of organoiron chemistry to the construction of sterically congested quaternary carbon centers

Article abstract of DOI:10.1021/jo9705475

A synthesis of racemic stemodinone is described, using tricarbonyl(1-5- η-4-methoxy-1,3-dimethylcyclohexadienyl)iron(I) hexafluorophosphate (9) as an electrophile that is the A-ring precursor. Reaction of 9 with the tin enolate 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 alkylation. Installation of the D ring and manipulation to give the final product followed transformations precedented with this series of compounds.