已经开发了带有L-脯氨酸衍生的N 4配体的新型锰催化剂,其能够使用叔丁基氢过氧化物作为氧化剂实现烯烃的无酸不对称环氧化。大小与配位体袋完全匹配的各种烯烃可以转化为具有出色对映选择性的环氧化物。较小的配体口袋也有利于简单烯烃的对映选择性环氧化。低温喷雾电离质谱实验表明,Mn IV O物种可作为活性环氧化物种。
Highly Enantioselective Epoxidation of Multisubstituted Enones Catalyzed by Non‐Heme Iron Catalysts
作者:Bin Wang、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1002/chem.201200992
日期:2012.6.11
Iron(II) efficiency: The iron complexes of N4 ligands, derivedfrom proline and benzimidazole, exhibited an unprecedented activity and enantioselectivity for the epoxidation of a variety of di‐ and trisubstituted enones (see scheme). This system, based on synthetic non‐heme iron catalysts, provides ready access to a wide range of epoxyketones of high enantiomeric purity.
Manganese Catalysts with<i>C</i><sub>1</sub>-Symmetric N<sub>4</sub>Ligand for Enantioselective Epoxidation of Olefins
作者:Bin Wang、Chengxia Miao、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1002/chem.201103802
日期:2012.5.29
Bioinspired manganese complexes based on N4 ligands, with a more rigid, chiral diamine derived from proline and two benzimidazoles, were synthesized and applied to epoxidize olefins with hydrogen peroxide as a clean oxidant. Notably, 60–99 % isolated yields and excellent ee values (up to 95 %) were obtained by using low catalyst loadings (0.01–0.2 mol %; see scheme; F green, S yellow).