Scope and limitations of chiral bis(oxazoline) ligands in the copper-catalysed asymmetric cyclopropanation of trisubstituted alkenes
作者:Niels Østergaard、Jakob F Jensen、David Tanner
DOI:10.1016/s0040-4020(01)00583-x
日期:2001.7
A series of derivatives of 3-methyl-2-buten-1-ol has been used to test the scope and limitations of the copper-catalysed asymmetric cyclopropanation of trisubstituted alkenes by ethyl diazoacetate in the presence of C2-symmetric bis(oxazoline) ligands. In the best case, a trans/cis ratio of 91:9, with 92% ee for the major isomer, was obtained from the reaction of the p-methoxybenzoate derivative. The
已使用一系列3-甲基-2-丁烯-1-醇衍生物来测试在C 2对称双(恶唑啉)存在下铜重氮烯丙基乙酸乙酯对三取代烯烃的不对称环丙烷化的范围和局限性配体。在最佳情况下,对-甲氧基苯甲酸酯衍生物的反应获得的反式/顺式比例为91:9,主要异构体的ee为92%。对于80:20非对映异构体混合物(乙酸衍生物)的反式异构体,最高ee为95%。