Asymmetric 1,4-Addition of Oxazolones to Nitroalkenes by Bifunctional Cinchona Alkaloid Thiourea Organocatalysts: Synthesis of α,α-Disubstituted α-Amino Acids
作者:José Alemán、Andrea Milelli、Silvia Cabrera、Efraim Reyes、Karl Anker Jørgensen
DOI:10.1002/chem.200802030
日期:2008.12.8
good enantioselectivities (up to 92 % ee). The reaction can be performed on a large scale. The optically active oxazolone-nitroalkene addition products can be opened in a one-pot reaction to the corresponding ester-amide derivatives. Additional transformations are also presented, such as the synthesis of amino esters, amino acids, and transformation into 3,4-disubstituted pyrrolidin-2-ones.
提出了一种使用不对称有机催化合成旋光性α,α-季α-氨基酸的简便方法。在硫脲金鸡纳衍生物催化的硝基烯烃中添加恶唑酮可提供相应的α,α-季α-氨基酸衍生物,具有良好的收率,出色的非对映选择性(高达98%dr)以及从中等到良好的对映选择性(高达92%ee) )。该反应可以大规模进行。旋光的恶唑酮-硝基烯烃加成产物可以在一锅反应中与相应的酯-酰胺衍生物开环。还提出了另外的转化,例如氨基酯,氨基酸的合成,以及转化成3,4-二取代的吡咯烷-2-酮。