Interaction of fluoroalkyl-containing ?-diketones with amines
摘要:
The composition of products of the interaction of asymmetric fluoroalkyl-containing beta-diketones with amines was studied. Mixtures of regioisomeric beta-aminovinylketones and products of cleavage and secondary condensation are formed, depending on the temperature, the solvent, the nature of the fluorinated and nonfluorinated substituents in the beta-diketone, and the basicity of the amine. The major product is a beta-aminovinylketone in which the NH2 group is removed from the fluoroalkyl substituent. No beta-aminovinylimines, products of condensation involving two electrophilic centers, were observed.
A highly efficient and regioselectivedirectC–H trifluoromethylation of pyridine based on an N-methylpyridine quaternary ammonium activation strategy has been developed. A variety of trifluoromethylpyridines can be obtained in good yield and excellent regioselectivity by treating the pyridinium iodide salts with trifluoroacetic acid in the presence of silver carbonate in N,N-dimethylformamide. The
Efficient and convenient entry to β-hydroxy-β-trifluoromethyl-β-substituted ketones and 2,6-disubstituted 4-trifluoromethylpyridines based on the reaction of trifluoromethyl ketones with enamines or imines
The reactions of trifluoromethyl ketones with enamines or imines are described. The reaction of trifluoroacetone with enamines or imines followed by hydrolysis gave the corresponding β-hydroxy-β-trifluoromethyl-β-methyl ketones in good yields. The reaction of trifluoromethylated β-diketones with enamines in the presence of ammonium acetate gave 4-trifluoromethylated pyridines exclusively in good yields, without any detectable amount of regioisomers.
Regioselective Synthesis of 2,4-Diaryl-6-trifluoromethylated Pyridines through Copper-Catalyzed Cyclization of CF<sub>3</sub>-Ynones and Vinyl Azides
作者:Jixin Wang、Da Ba、Mengqi Yang、Guolin Cheng、Lianhui Wang
DOI:10.1021/acs.joc.1c00275
日期:2021.5.7
copper-catalyzed cyclization of readily available vinyl azides with CF3-ynones is steadily achieved under mild conditions to furnish the versatile 2,4-diaryl-6-trifluoromethylated pyridineproducts, which are of great interest in medicinal chemistry. The generation of the vinyl iminophosphorane intermediates from vinyl azides through the Staudinger–Meyer reaction ensures the subsequent 1,4-addition process with
A multicomponent Kröhnke reaction of chalcones with 1-(3,3,3-trifluoro-2-oxopropyl)pyridin-1-ium bromide and ammonium acetate is described. This strategy allows efficiently construction of a series of 2-trifluoromethyl pyridines with broad functional groups.