Ru-Catalyzed Asymmetric Hydrogenation of 3-Oxoglutaric Acid Derivatives via Solvent-Assisted Pinpoint Recognition of Carbonyls in Close Chemical Propinquity
作者:Wanfang Li、Xin Ma、Weizheng Fan、Xiaoming Tao、Xiaoming Li、Xiaomin Xie、Zhaoguo Zhang
DOI:10.1021/ol201406w
日期:2011.8.5
Upon comparison of hydrogenation rates of various beta-ketocarboxylic acid derivatives, beta-ketoamides were found to be hydrogenated slightly faster than beta-ketoesters in EtOH in the presence of [RuCl(benzene)(S)-SunPhos]Cl at 70 degrees C with 20 bar of hydrogen. In THF these differences were so sharpened that beta-ketoamides were hydrogenated even faster than In EtOH while the esters were extremely slow. Based on these findings, a series of 3-oxoglutaric acid derived with ester and amide moieties on the two ends were hydrogenated to 3-hydroxyl products with high enantioselectivities.