这里描述的是路易斯酸性硼烷催化剂介导的α,β-不饱和醛的还原胺化/氢化硅烷化级联。本反应系统提供了一种单罐合成路线,可通往其他先前催化无法达到的β-甲硅烷基化仲胺。对亚胺的甲硅烷基化还原进行的比较1 H NMR研究表明,伯胺反应物的空间体积极大地影响了催化效率和区域选择性。该策略适用于广泛的底物,并适用于一锅克级合成。此外,还发现非对映选择性地引入β-甲硅烷基是可行的(dr高达71:29)。
Cooperative <i>N</i>-Heterocyclic Carbene/Palladium-Catalyzed Umpolung 1,4-Addition of Vinyl Bromides to Enals
作者:Bo Ling、Wenjun Yang、Yan-En Wang、Jianyou Mao
DOI:10.1021/acs.orglett.0c03654
日期:2020.12.18
A highly stereoselective umpolung 1,4-addition of vinylbromides to enals is enabled by NHC/palladium cooperative catalysis, generating various valuable γ,δ-unsaturated carbonyl derivatives in excellent yields (up to 90%). A detailed mechanism investigation indicates the NHC act as both organocatalyst and ligand for palladium during this system.