Phase-Transfer-Catalyzed Asymmetric Synthesis of Chiral<i>N</i>-Substituted Pyrazoles by Aza-Michael Reaction
作者:Su-Jeong Lee、Ju-Yeon Bae、Chang-Woo Cho
DOI:10.1002/ejoc.201500940
日期:2015.9
cinchona-based phase-transfer-catalyzed asymmetric aza-Michael reaction of pyrazole with various α,β-unsaturated ketones has been developed for the preparation of chiral N-substituted pyrazoles. This reaction provided the desired products in good yields (up to 99 %) with excellent enantioselectivities (87–94 % ee). In addition, the reaction of 3-methyl-1H-pyrazole, an unsymmetrically substituted pyrazole
已经开发了一种有效的基于金鸡纳的相转移催化的吡唑与各种 α,β-不饱和酮的不对称氮杂-迈克尔反应,用于制备手性 N-取代吡唑。该反应以良好的收率(高达 99%)提供了所需的产物,并具有出色的对映选择性(87-94% ee)。此外,3-甲基-1H-吡唑,一种不对称取代的吡唑,用α,β-不饱和酮处理,得到相应的手性N-取代吡唑,产率高(高达99%),具有优异的对映选择性( 90–92 % ee) 和高达 9:1 的区域异构比率。