By employing an unprecedented CBS-catalyzed reductive desymmetrization of the readily available meso-diketone 2, both enantiomers of the cyclohexenone precursor 3 can be synthesized in up to 92% yield and 98% ee. From this precursor, 4-hydroxycyclohexenone (1) is easily liberated by a retro Diels-Alder reaction.
asymmetric catalysis - oxazaborolidines - cyclohexenones - reduction - desymmetrization