A metal‐free approach for the synthesis of 5‐trifluoromethyl‐1,2,4‐triazoles from trifluoroacetimidoyl chlorides and hydrazones has been achieved under aerobic oxidative conditions. The reaction proceeds through a cascade base‐promoted intermolecular C−N bond formation and iodine‐mediated intramolecular C−N bond oxidative coupling sequence. The protocol features broad substrate scope and can be scaled
A palladium-catalyzed four-component carbonylativecyclization reaction for the expeditious construction of trifluoromethyl-containing trisubstituted imidazoles has been achieved. With readily accessible trifluoroacetimidoyl chlorides, propargyl amines, and diaryliodonium salts as the starting materials, the carbonylative transformation proceeds smoothly under mild conditions to enable the formation
Base-mediated [3+2] annulation of trifluoroacetimidoyl chlorides and isocyanides: An improved approach for regioselective synthesis of 5-trifluoromethyl-imidazoles
作者:Sipei Hu、Hefei Yang、Zhengkai Chen、Xiao-Feng Wu
DOI:10.1016/j.tet.2020.131168
日期:2020.5
A t-BuOK-mediated [3 + 2] cycloaddition reaction of trifluoroacetimidoyl chlorides and active methylene isocyanides for the synthesis of 5-trifluoromethyl-imidazoles has been developed. Under mild reaction conditions, the transformation proceeds smoothly in the presence of t-BuOK to afford an array of structurally diverse 5-trifluoromethyl-imidazoles with high efficiency.
Electrochemical Oxidation of N,N'-Disubstituted Trifluoroethanimidamides. An Approach to N-Substituted 2-(Trifluoromethyl)benzimidazoles
作者:Kenji Uneyama、Masafumi Kobayashi
DOI:10.1021/jo00090a017
日期:1994.6
Electrochemical oxidation of N,N'-disubstituted trifluoroethanimidamides 11 in dry acetonitrile and in aqueous acetonitrile provided N-substituted 2-(trifluoromethyl)benzimidazoles 15 and N-1-(4-oxo-2,5-cyclohexadien-1-ylidene)-N-2-substituted-2,2,2-trifluoroethanimidamides (p-benzoquinone imine derivatives) 20, respectively. In dry acetonitrile, electron-donating para substituents in the N,N'-diaryl derivatives strongly promoted the formation of benzimidazoles, whereas N-alkyl-N'(4-methoxyphenyl) derivatives provided rather complex mixtures of 11,20, and polymeric compounds. In wet acetonitrile, p-benzoquinone imines 20 were major products regardless of the substituents. An ECEC process via two-electron oxidation is proposed.