Dynamic Kinetic Resolution of Benzoins by Lipase−Metal Combo Catalysis
journal contributionposted on 29.09.2006, 00:00 by Pilar Hoyos, María Fernández, José Vicente Sinisterra, Andrés R. Alcántara
The synthesis of some noncommercial racemic 1,2-diaryl-2-hydroxyethanones (benzoins) is described, optimizing the previously reported methodologies. In a further step, the kinetic resolution of these substrates is reported, obtaining conversions of around 50% and eep higher than 99% in very short reaction times. As enzymatic catalyst, after screening of several enzymes, the lipase TL (from Pseudomonas stutzeri) was the most efficient, working in an organic solvent with a very low log P value, such as THF. Finally, the dynamic−kinetic resolution of different benzoins using a lipase−ruthenium-catalyzed transesterification in organic solvents is described for the first time, obtaining conversions up to 90% maintaining the excellent enantioselectivity in all cases.