Introducing the Chiral Transient Directing Group Strategy to Rhodium(III)‐Catalyzed Asymmetric C−H Activation
作者:Guozhu Li、Jijun Jiang、Hui Xie、Jun Wang
DOI:10.1002/chem.201900762
日期:2019.3.27
The chiral transient directing group (TDG) strategy has been successfully introduced to the rhodium(III)‐catalyzed asymmetric C−H activation. In the presence of a catalytic amount of a chiral amine and an achiral rhodium catalyst, various chiral phthalides were synthesized from simple aldehydes with high chemoselectivity, regioselectivity, and enantioselectivity (53 examples, up to 73 % yield and >99 % ee)
手性瞬态导向基团(TDG)策略已成功地引入到铑(III)催化的不对称CH活化中。在催化量的手性胺和非手性铑催化剂的存在下,由简单的醛合成了各种手性邻苯二甲酸盐,具有高的化学选择性,区域选择性和对映选择性(53个实例,收率高达73%,ee大于99%) )。值得注意的是,手性诱导模型不同于先前报道的使用氨基酸衍生物和钯盐的手性TDG系统。由手性胺和醛原位生成的亚氨基基团起单齿TDG的作用,促进CH活化,立体选择性地生成带有手性金属中心的手性Rhodacycle。此外,在立体式将C-Rh键加至醛中时,而不是在CH活化步骤中,会创建并控制产品的立体中心。