2-[(Imidazolylthio)methyl]pyrrolidine as a Trifunctional Organocatalyst for the Highly Asymmetric Michael Addition of Ketones to Nitroolefins
作者:Dan-Qian Xu、Li-Ping Wang、Shu-Ping Luo、Yi-Feng Wang、Shuai Zhang、Zhen-Yuan Xu
DOI:10.1002/ejoc.200700856
日期:2008.2
The direct asymmetric Michael addition of ketones to nitroolefins catalyzed by 2-[(imidazol-2-ylthio)methyl]pyrrolidine, constructed from natural L-proline and imidazolylthio platforms, with salicylic acid as a co-catalyst has been developed to give the products in high yields (up to 95 %) and with excellent enantioselectivities (up to 99 % ee). The highly efficient catalytic performance may be attributed
2-[(咪唑-2-基硫基)甲基]吡咯烷催化酮与硝基烯烃的直接不对称迈克尔加成反应,由天然L-脯氨酸和咪唑硫基平台构建,水杨酸作为助催化剂得到了产物以高产率(高达 95 %)和出色的对映选择性(高达 99 % ee)。高效的催化性能可能归因于三官能有机催化剂和助催化剂水杨酸对迈克尔底物的双重活化,通过氢键和静电相互作用的协同作用形成稳定的过渡态复合物。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)