Enedione 1 and related rac- and optically active enones 2 bearing a hydroxyl- 2a or a protected- 2b-c or an activated- 2d 4-hydroxyl group at C-4 have been efficiently synthesized from cheap and readily available starting materials.
(+)- and (-)-5,5-Dimethyl-4-hydroxy-2-cyclopentenone 1 were efficiently synthesized by the dissymmetrization of meso diol 2 with lipase-catalyzed acetylation as a key step. The synthesis of (+)-5,5-dimethyl-4-hydroxy-2-cyclopentenone was also carried out by the chemical conversion of (-)-pantolactone 6.