Discovery of aromatic components with excellent fragrance properties and biological activities: β-ionols with antimelanogenetic effects and their asymmetric syntheses.

Both enantiomers of dihydro-β-ionol and β-ionol, contained in the aromatic components of Osmanthus flower and of Hakuto peach, were obtained with high optical purity by lipase-catalyzed kinetic resolution of the racemates. It was found that all these enantiomers had different characteristic favorable scents and high antimelanogenetic effects. The absolute configuration and the enantiomer ratios of dihydro-β-ionol in the aromatic components of Osmanthus flower and of Hakuto peach were determined. The asymmetric synthesis of (R)-dihydro-β-ionol, one of the most valuable raw materials for fragrance and flavor, was performed from inexpensive β-ionone via lipase-catalyzed dynamic kinetic resolution followed by reduction.