Organocatalytic Asymmetric Michael Addition of 5<i>H</i>-Oxazol-4-ones to Nitroolefins
作者:Baokun Qiao、Yongqiang An、Qian Liu、Wenguo Yang、Hongjun Liu、Juan Shen、Lin Yan、Zhiyong Jiang
DOI:10.1021/ol401062z
日期:2013.5.17
The first organocatalytic asymmetric Michael addition of 5H-oxazol-4-ones to nitroolefins has been developed. In the presence of easily prepared L-tert-leucine-derived tertiary amine/thiourea catalyst, the Michael addition of 5H-oxazol-4-ones to nitroolefins proceeded in an excellent diastereo- and enantioselective manner (up to 99% ee and >19:1 dr). The Michael adducts obtained are valuable precursors for the synthesis of chiral alpha-alkyl-alpha-hydroxy carboxylic acid derivatives, which represent a series of versatile building blocks in many biologically active compounds.