Enantioselective Addition of Nitromethane to 2-Acylpyridine N-Oxides. Expanding the Generation of Quaternary Stereocenters with the Henry Reaction
摘要:
The direct asymmetric Henry reaction with prochiral ketones, leading to tertiary nitroaldols, is an elusive reaction so far limited to a reduced number of reactive substrates such as trifluoromethyl ketones or alpha-keto carbonyl compounds. Expanding the scope of this important reaction, the direct asymmetric addition of nitromethane to 2-acylpyridine N-oxides catalyzed by a BOX-Cu(II) complex to give the corresponding pyridine-derived tertiary nitroaldols having a quaternary stereogenic center with variable yields and good enantioselectivity, is described.
Metal-, Photocatalyst-, and Light-Free Minisci C–H Acetylation of N-Heteroarenes with Vinyl Ethers
作者:Jianyang Dong、Jianhua Liu、Hongjian Song、Yuxiu Liu、Qingmin Wang
DOI:10.1021/acs.orglett.1c01310
日期:2021.6.4
Herein, we report a mild, operationally simple method for MinisciC–H acetylation of N-heteroarenes using vinyl ethers as robust, inexpensive acetyl sources. The reactions do not require a conventional photocatalysis, electrocatalysis, metal catalysis, light activation, or high temperature. This method is thus significantly more sustainable than previously reported methods in terms of cost, reagent