One-pot synthesis of 2-(trifluoromethyl)pyridines from N-silyl-1-aza-allyl anions with trifluoroacetylketene diethyl ketal or (E )-1,1,1-trifluoro-4-phenylbut-3-en-2-one
作者:Takeo Konakahara、Marhaba Hojahmat、Sanae Tamura
DOI:10.1039/a904567h
日期:——
The reaction of N-silyl-1-aza-allyl anions with trifluoroacetylketene diethyl ketal and (E)-1,1,1-trifluoro-4-phenylbut-3-en-2-one are described. The anions, which were prepared from an α-silyl carbanion of 3-methyl-5-(trimethylsilylmethyl)isoxazole [or 3-methyl-2-(trimethylsilylmethyl)pyridine] and para-substituted benzonitriles (R = H, p-Me, p-OMe, p-Cl, p-CF3), reacted with a slight excess of trifluoroacetylketene diethyl ketal or (E)-1,1,1-trifluoro-4-phenylbut-3-en-2-one in dry tetrahydrofuran to afford the corresponding 2-(trifluoromethyl)pyridine derivatives in 75, 71, 78, 48, 46, 60, 83% yield, respectively.
描述了N-甲硅烷基-1-氮杂-烯丙基阴离子与三氟乙酰乙烯酮二乙基缩酮和(E)-1,1,1-三氟-4-苯基丁-3-en-2-酮的反应。阴离子由 3-甲基-5-(三甲基甲硅烷基甲基)异恶唑 [或 3-甲基-2-(三甲基甲硅烷基甲基)吡啶] 的 α-甲硅烷基碳负离子和对位取代的苯甲腈(R = H、p-Me、 p-OMe、p-Cl、p-CF3),与稍微过量的三氟乙酰基乙烯酮二乙基缩酮或(E)-1,1,1-三氟-4-苯基丁-3-en-2-酮在干燥四氢呋喃中反应,分别得到相应的2-(三氟甲基)吡啶衍生物,产率为75%、71%、78%、48%、46%、60%、83%。