Organocatalytic Enantioselective Michael-Addition of Malonic Acid Half-Thioesters to β-Nitroolefins: From Mimicry of Polyketide Synthases to Scalable Synthesis of γ-Amino Acids
作者:Han Yong Bae、Surajit Some、Jae Heon Lee、Ju-Young Kim、Myoung Jong Song、Sungyul Lee、Yong Jian Zhang、Choong Eui Song
DOI:10.1002/adsc.201100458
日期:2011.11
Highly enantioselective biomimetic Michael addition reactions of malonic acid half thioesters (MAHTs) to a variety of nitroolefins, affording the optically active γ-amino acid precursors, were developed by employing the Cinchona-based squaramides (up to >99% ee). Remarkably, this biomimetic process is enantioconvergent, a highly desirable feature of a catalytic asymmetric reaction, whereby E/Z-isomers
丙二酸半硫酯(MAHT)与多种硝基烯烃的高度对映选择性仿生迈克尔加成反应,提供了具有光学活性的γ-氨基酸前体,这是通过使用基于Cinchona的方酰胺(最高> 99%ee)开发的。值得注意的是,这种仿生过程是对映收敛的,这是催化不对称反应的高度期望的特征,因此E / Z硝基烯烃的β-异构体提供相同的产物对映体。这种有机催化方案的合成效用还在药学上重要的γ-氨基酸(如巴氯芬)的正式合成中得到了证明。而且,显示出对催化剂-底物配合物的量子化学分析可对观察到的催化活性的起源提供详细的和仪器上的见解。