Diastereo- and Enantioselective Synthesis of β-Hydroxy-α-Amino Acids: Application to the Synthesis of a Key Intermediate for Lactacystin
作者:Qiong Li、Shao-Bo Yang、Zhihui Zhang、Lei Li、Peng-Fei Xu
DOI:10.1021/jo8023973
日期:2009.2.20
β-hydroxy-α-amino acids is described. Nucleophilic addition of enolates of tricyclic iminolactones 1a and 1b to aldehydes in the presence of 6 equiv of lithium chloride in THF at −78 °C leads to aldol adducts in good yield (63−86%) and high diastereoselectivity (up to >25:1 dr). Subsequently, hydrolysis of the aldol adducts under acidic conditions leads to the corresponding β-hydroxy-α-amino acids in good yields
描述了用于制备β-羟基-α-氨基酸的高效和立体选择方法的发展。在−78°C的条件下,在THF中存在6当量氯化锂的情况下,将三环亚氨基内酯1a和1b的烯酸酯亲核加成到醛中,得到高收率(63-86%)和高非对映选择性(高达> 25的醛醇加合物): 1博士)。随后,在酸性条件下醛醇加合物的水解导致相应的β-羟基-α-氨基酸以良好的产率(高达83%)和优异的对映体过量(99%ee)具有良好的手性助剂6和7的回收率。7。该方法学适用于乳酸菌素关键中间体及其几种异构体的简便合成。