Practical Copper-Catalyzed Asymmetric Synthesis of Chiral Chrysanthemic Acid Esters
作者:Makoto Itagaki、Katsuhiro Suenobu
DOI:10.1021/op060238t
日期:2007.5.1
Practical copper salicylaldimine complex catalysts have been developed for the asymmetric synthesis of chiral chrysanthemic acid esters by the cyclopropanation reaction of 2,5-dimethyl-2,4-hexadiene with tert-butyl diazoacetate. First, the effects of the substituents on the salicylaldehyde moiety in the copper salicylaldimine complex (copper Schiff base complex) on the catalytic activity and the stereoselectivities
已开发出实用的水杨醛亚胺铜络合物催化剂,用于通过2,5-二甲基-2,4-己二烯与叔胺的环丙烷化反应来不对称合成手性菊酸酯。重氮乙酸丁酯。首先,研究了取代基对铜水杨醛亚胺铜配合物(铜席夫碱配合物)中水杨醛部分的催化活性和立体选择性的影响。结果,发现在5-位的氢被水杨醛部分上的硝基取代可以提高催化效率。另外,发现铜席夫碱配合物与路易斯酸的组合催化剂还提高了催化效率,并在催化剂负载为0.1摩尔%的情况下,在20℃下达到了90%的化学产率和91%的ee。此外,使用密度泛函计算研究了铜席夫碱配合物催化的环丙烷化反应的不对称诱导机理。