Enantioselective (3+2) cycloaddition <i>via</i> N-heterocyclic carbene-catalyzed addition of homoenolates to cyclic <i>N</i>-sulfonyl trifluoromethylated ketimines: synthesis of fused N-heterocycle γ-lactams
作者:Zhen-Zhen Zhang、Yongna Zhang、Hui-Xin Duan、Zhuo-Fei Deng、You-Qing Wang
DOI:10.1039/c9cc09269b
日期:——
An enantioselective (3+2) cycloaddition of enals and cyclic N-sulfonyl trifluoromethyl ketimines via N-heterocyclic carbene-catalyzed homoenolateaddition is described. This reaction can efficiently construct fused N-heterocycle γ-lactams bearing two adjacent chiral centers with >20 : 1 dr and 94-99% ee, with one chiral center as a trifluoromethylated α-tetrasubstituted carbon stereocenter.
TiCl<sub>4</sub>-Catalyzed Friedel–Crafts Reaction of Trifluoroacetaldehyde Ethyl Hemiacetal (TFAE)
作者:Jing Zhang、Yong-Jun Chen、Liang Zhang
DOI:10.1080/00397911.2010.516860
日期:2011.10.15
Abstract The TiCl4-catalyzed Friedel–Craftsreaction with trifluoroacetaldehyde ethyl hemiacetal is shown to serve as an efficient route for the synthesis of CF3-substitituted compounds of biological and synthetic importance, producing 2,2,2-trifluoroethyl phenols in good yields under mild conditions.