Kang Tengfei, Cao Weidi, Hou Liuzhen, Tang Qiong, Zou Sijia, Liu Xiaohua, Feng Xiaoming
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
Angew Chem Int Ed Engl. 2019 Feb 18;58(8):2464-2468. doi: 10.1002/anie.201810961. Epub 2019 Jan 30.
A new catalytic asymmetric tandem α-alkenyl addition/proton shift reaction of silyl enol ethers with ketimines was serendipitously discovered in the presence of chiral N,N'-dioxide/Zn complexes. The proton shift preferentially proceeded instead of a silyl shift after α-alkenyl addition of silyl enol ether to the ketimine. A wide range of β-amino silyl enol ethers were synthesized in high yields with good to excellent ee values. Control experiments suggest that the Mukaiyama-Mannich reaction and tandem α-alkenyl addition/proton shift reaction are competitive reactions in the current catalytic system. The obtained β-amino silyl enol ethers were easily transformed into β-fluoroamines containing two vicinal tetrasubstituted carbon centers.
在手性N,N'-二氧化物/锌配合物存在下，意外发现了一种甲硅烷基烯醇醚与酮亚胺的新型催化不对称串联α-烯基加成/质子转移反应。甲硅烷基烯醇醚与酮亚胺进行α-烯基加成后，优先发生质子转移而非硅基转移。以良好至优异的对映体过量值高产率合成了一系列β-氨基甲硅烷基烯醇醚。对照实验表明，在当前催化体系中， Mukaiyama-Mannich反应和串联α-烯基加成/质子转移反应是竞争反应。所得到的β-氨基甲硅烷基烯醇醚可轻松转化为含有两个相邻四取代碳中心的β-氟胺。
