Combining chiral elements in asymmetric phase-transfer catalysts: styrene oxide and chiral α,α-disubstituted pyrroline and piperidine derived structures
作者:Gregory N. Grover、Walter E. Kowtoniuk、Darren K. MacFarland
DOI:10.1016/j.tetlet.2005.10.141
日期:2006.1
styrene oxide and 2,5-dimethylpyrroline, is described. Catalytic testing using standard glycine imino ester alkylations shows good yields and moderate to good enantioselectivities with a surprising change in enantioselectivity over the course of the reaction. Alkylation of the β-hydroxyl group lead to catalysts with improved selectivity and a larger change in enantioselectivity during the reaction.
描述了一种新的不对称相转移催化剂,该催化剂是通过手性结构单元苯乙烯氧化物和2,5-二甲基吡咯啉的组合而设计的。使用标准甘氨酸亚氨基酯烷基化的催化测试显示出良好的产率和中等至良好的对映选择性,并且在反应过程中对映选择性发生了令人惊讶的变化。β-羟基的烷基化导致催化剂在反应过程中具有改进的选择性和对映选择性的较大变化。