Synthesis and revision of the relative configuration of fudecalone

We synthesized the proposed structure of fudecalone, whose NMR spectral data were not identical with those of the natural compound. As our synthetic fudecalone was a conformational isomer of the reported structure, we first investigated conformational isomerization. However, all our attempts resulted in failure, and we then changed the strategy to the synthesis of diastereomers. Finally, we found the trans-octalone derivative showed the identical NMR spectrum with that of natural fudecalone, and the relative configuration was determined to be 1S*, 3aS*, 6aS*, 10aS*.