Preparation of 3-Iodoquinolines from N-Tosyl-2-propynylamines with Diaryliodonium Triflate and N-Iodosuccinimide.

4-Aryl and 4-alkyl substituted 3-iodoquinolines could be smoothly obtained in one pot by treating N-tosyl-2-propynylamines with diaryliodonium triflate in the presence of K3PO4 and a catalytic amount of CuCl at room temperature, followed by treatment with N-iodosuccinimide and BF3·OEt2 at 0 °C, and then NaOH in methanol solution. The product, 3-iodo-4-phenylquinoline was smoothly transformed into 4-phenylquinoline with zinc; 4-phenyl-3-toluenesulfenylquinoline with toluenethiol, K2CO3, and CuI; 4-phenyl-3-phenylethynylquinoline with the Sonogashira coupling reaction; 4-phenyl-3-styrylquinoline with the Heck coupling reaction; 3,4-diphenylquinoline with the Suzuki-Miyaura coupling reaction; 2-cyclohexyl-3-iodo-4-phenylquinoline with cyclohexanecarboxylic acid, Ag2CO3, and K2S2O8; and 3-iodo-2-(2',5'-dioxan-1'-yl)-4-phenylquinoline with benzoyl peroxide in dioxane.