demonstrate novel properties as asymmetric catalysts. We report the three-dimensional structures of two such asymmetric catalysts (crystals A and B) for Strecker alpha,alpha-disubstituted amino acidsynthesis. These complexes are constructed via assembly of the same chiral modules derived from d-glucose, but their assembly modes differ. The enantioselectivity in the Strecker reaction was dramatically switched
自组装手性多金属配合物通常表现出作为不对称催化剂的新特性。我们报告了用于 Strecker α、α-二取代氨基酸合成的两种这种不对称催化剂(晶体 A 和 B)的三维结构。这些复合物是通过组装来自 d-葡萄糖的相同手性模块构建的,但它们的组装模式不同。Strecker 反应中的对映选择性发生了显着变化,具体取决于使用的组装模式:原位生成的催化剂,其结构由晶体 B 或晶体 A 表示。这些发现提供了对高阶结构的功能重要性的洞察一种人工催化剂。
Catalytic Asymmetric Total Synthesis of (+)-Lactacystin
作者:Nobuhisa Fukuda、Kazuki Sasaki、T. V. R. S. Sastry、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/jo0524223
日期:2006.2.1
Total synthesis of (+)-lactacystin, a potent and selective proteasome inhibitor, was accomplished using a catalytic enantioselective Strecker reaction of a ketoimine as the initial key step. An enone-derived N-phosphinoyl ketoimine 7 was selected as a stable masked α-hydroxy ketoimine analogue. Excellent enantioselectivity (98% ee) and practical catalyst activity were produced under the optimized catalyst