Bielefeld University, Department of Chemistry, Organic and Bioorganic Chemistry, Universitätsstr. 25, 33615 Bielefeld, Germany.
Beilstein J Org Chem. 2009 Sep 14;5:43. doi: 10.3762/bjoc.5.43.
Novel procedures have been developed to condense benzaldehyde effectively with beta-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral beta-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised beta(2)-amino acids containing acid-labile protected side chains. Diastereoselective alkylation of the tetrahydropyrimidinone is followed by a chemoselective two step degradation of the heterocycle to release the free beta(2)-amino acid. In the course of this study, an L-asparagine derivative was condensed with benzaldehyde and subsequently converted to orthogonally protected (R)-beta(2)-homoaspartate.
已经开发出了新的方法，有效地将β-氨基酸酰胺与苯甲醛缩合生成环状苄基缩氨醛。杂环的双碳酸酯保护作用得到了完全保护的手性β-丙氨酸衍生物。这些衍生物可作为含酸不稳定保护侧链的功能化β(2)-氨基酸不对称合成的通用前体。四氢嘧啶酮的立体选择性烷基化反应之后，杂环的化学选择性两步降解反应可释放出游离的β(2)-氨基酸。在这项研究中，L-天冬酰胺衍生物与苯甲醛缩合，随后转化为正交保护的(R)-β(2)-同型天冬氨酸。
