Getting more for less: In the presence of H2 and a base, air‐ and moisture‐tolerant RuII complexes catalyze the hydrogenation of ketones and aldehydes with excellent activity and chemoselectivity, and with enantioselectivity of up to 95 % under mild conditions. The ratio of substrate to catalyst can be lowered to 106:1. The reactions tolerate scale‐up and can be carried out with almost no solvent. A base‐free
with a lipase produced the regio- and enantioconvergent transformation of racemic allyl alcohols (1 or 2) into optically active allyl esters. In this system, the vanadium compounds catalyzed the continuous racemization of the alcohols along with the transposition of the hydroxyl group, while the lipase effected the chemo- and enantioselective esterification to achieve the dynamickineticresolution.
Discovery of Aromatic Components with Excellent Fragrance Properties and Biological Activities: β-Ionols with Antimelanogenetic Effects and Their Asymmetric Syntheses
high optical purity by lipase-catalyzedkineticresolution 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