Rajkumar Subramani, Wang Jiawen, Zheng Sujuan, Wang Donglei, Ye Xueqian, Li Xuejiao, Peng Qian, Yang Xiaoyu
School of Physical Science and Technology ShanghaiTech University, Shanghai, 201210, China.
State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
Angew Chem Int Ed Engl. 2018 Oct 8;57(41):13489-13494. doi: 10.1002/anie.201807010. Epub 2018 Sep 17.
The regioselective and enantioselective synthesis of β-indolyl cyclopentenamides, a versatile chiral building block, by asymmetric addition of indoles to α,β-unsaturated iminium intermediates has been achieved through chiral anion catalysis. Key to the success of this methodology is the generation of a chiral anion-paired ketone-type α,β-unsaturated iminium intermediate from α-hydroxy enamides. Preliminary mechanistic studies and DFT calculations are consistent with a mechanism involving multiple, concurrent pathways for isomerization of the initially formed azaallylcation into the key α,β-unsaturated iminium intermediate, all mediated by the phosphoric acid catalyst.
通过手性阴离子催化，将吲哚对α,β-不饱和亚胺鎓中间体进行不对称加成，实现了多功能手性砌块β-吲哚基环戊烯酰胺的区域选择性和对映选择性合成。该方法成功的关键在于由α-羟基酰胺生成手性阴离子配对的酮型α,β-不饱和亚胺鎓中间体。初步机理研究和密度泛函理论计算与一种机理相符，该机理涉及最初形成的氮杂烯丙基阳离子异构化为关键的α,β-不饱和亚胺鎓中间体的多条并发途径，所有这些途径均由磷酸催化剂介导。
