A short, efficient, highly selective synthesis of (1R,3S)-(cis)-chrysanthemic acid through the microbiological reduction of 2,2,5,5-tetramethyl-1,4-cyclohexanedione
The Baeyer-Villiger-like oxidation of (R,S)-2,2,5,5-tetramethyl-4-hydroxy -cyclohexanone by several fungal strains was highly enantioselective, affording a rearranged (S)-hydroxy-γ-lactone. The recovery of the nearly optically pure (R)-hydroxyketone allowed its conversion to the enantiomeric (R)-hydroxylactone through a classical Baeyer-Villigeroxidation.