A Bench-Stable Homodinuclear Ni<sub>2</sub>−Schiff Base Complex for Catalytic Asymmetric Synthesis of α-Tetrasubstituted <i>anti</i>-α,β-Diamino Acid Surrogates
作者:Zhihua Chen、Hiroyuki Morimoto、Shigeki Matsunaga、Masakatsu Shibasaki
DOI:10.1021/ja710398q
日期:2008.2.1
Catalytic asymmetric direct Mannich-type reactions of α-substituted nitroacetates using a new bench-stable homodinuclear Ni2−Schiff base 1b complex are described. The Ni2−1b complex gave Mannich products, precursors for anti-α,β-diamino acids with an α-tetrasubstituted carbon stereocenter, in >99−91% ee. The Ni2−1b complex was also applicable to direct Mannich-type reactions of malonates and β-keto
描述了使用新的工作台稳定的同双核 Ni2-Schiff 碱 1b 复合物催化 α-取代硝基乙酸酯的不对称直接曼尼希型反应。Ni2-1b 复合物产生了 Mannich 产物,即具有 α-四取代碳立体中心的抗 α,β-二氨基酸的前体,ee 含量大于 99-91%。Ni2-1b 配合物也适用于丙二酸酯和 β-酮酯的直接曼尼希型反应,得到高立体选择性的产物(高达 99% ee,dr > 97:3)。初步的机理研究表明,双核镍金属中心在实现良好的反应性和高立体选择性方面起着关键作用。