A novel ligand-free palladium catalytic system with SO3H-functional ionic liquids as cocatalyst for amidocarbonylation reaction

摘要

Effects of Lewis acid BF3·OEt2,and BrCnsted acids TsOH,CF3COOH,H3PO4,and HClO4 as cocatalyst respectively on the ligand-free palladium-catalyzed amidocarbonylation were investigated.SO3H-functional ionic liquids 1-methyl-3-(4-sulfonic acid)butylimidazolium hydrosulfate[MIm(CH2)4SO3H][HSO4]and 1-methyl-3-(4-sulfonic acid)butyrlimidazolium triflate [MIm(CH2)4SO3H][OTf]were firstly employed as cocatalysts instead of these Lewis acid and Bronsted acids.By using a ligand-free and weak corrosive catalyst in situ prepared form PdBr2,LiBr·H2O,and[MIm(CH2)4SO3H][OTq,the amidocarbonylation of benzaldehyde,acetamide,and CO could proceed smoothly and afford N-acetyl-a-phenylglycine with yield of 58% in [C6mim]PF6 medium.