首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Asymmetric Mannich Reaction of Aryl Methyl Ketones with Cyclic Imines Benzo[e][1,2,3]oxathiazine 2,2‐Dioxides Catalyzed by Cinchona Alkaloid‐based Primary Amines
Authors:Xiao‐Yu Cui  Hui‐Xin Duan  Dr Yongna Zhang  Prof?Dr You‐Qing Wang
Institution:Key Laboratory of Polyoxometalate Chemistry of Henan Province, Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan, P. R. China
Abstract:Aryl ketones represent problematic substrates for asymmetric Mannich reactions due to a large steric hindrance exhibited by such compound species. A highly enantioselective direct Mannich reaction of aryl methyl ketones with cyclic imine benzoe]1,2,3]oxathiazine 2,2‐dioxides could be successfully carried out utilizing a combination of cinchona alkaloid‐derived primary amines with trifluoroacetic acid (TFA); the primary amines feature a superior catalytic efficacy over secondary amines with a variety of sterically hindered carbonyl compounds as substrates. The reaction proceeded well with various cyclic imines in 89–97 % ee and with various aryl methyl ketones in 85–98 % ee. Moreover, the aryl carbonyl of a Mannich product could be transformed to ketoxime, which further undergoes a Beckmann rearrangement to produce an amide compound while maintaining enantioselectivity.
Keywords:asymmetric catalysis  ketones  Mannich reaction  nitrogen heterocycles  organocatalysis
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号