Nickel<sup>II</sup>-catalyzed asymmetric photoenolization/Mannich reaction of (2-alkylphenyl) ketones
作者:Liangkun Yang、Wang-Yuren Li、Liuzhen Hou、Tangyu Zhan、Weidi Cao、Xiaohua Liu、Xiaoming Feng
DOI:10.1039/d2sc02721f
日期:——
A diastereo- and enantioselective photoenolization/Mannich (PEM) reaction of ortho-alkyl aromatic ketones with benzosulfonimides was established by utilizing a chiral N,N′-dioxide/Ni(OTf)2 complex as the Lewis acid catalyst. It afforded a series of benzosulfonamides and the corresponding ring-closure products, and a reversal of diastereoselectivity was observed through epimerization of the benzosulfonamide
利用手性N , N'-二氧化物/Ni(OTf) 2配合物作为Lewis酸催化剂,建立了邻烷基芳香酮与苯并磺酰亚胺的非对映和对映选择性光烯醇化/曼尼希(PEM)反应。它提供了一系列苯并磺酰胺和相应的闭环产物,并且通过苯磺酰胺产物在连续照射下的差向异构化观察到非对映选择性的逆转。在对照实验的基础上,阐明了添加剂LiNTf 2在实现高立体选择性中的作用。该 PEM 反应被提议进行直接亲核加成机制,而不是异狄尔斯-阿尔德/开环序列。提出了一种可能的具有光烯醇化过程的过渡态模型来解释高水平立体诱导的起源。