Iron Trichloride-Promoted Cyclization of o-Alkynylaryl Isocyanates: Synthesis of 3-(Chloromethylene)oxindoles
摘要:
Iron trichloride promotes the cationic cyclization of o-(arylethynyl)aryl isocyanates leading to 3-(arylchloromethylene)oxindoles which can be stereoselectively converted to (2)-3-(aminomethylene)ox in doles under straightforward conditions. When the alkyne is substituted by an alkyl group, activation of the allylic C-H bond also occurs producing 1,2-(dichloroalkylidene)oxindoles.
Herein, a palladium-catalyzed and ligand-controlled protocol for the divergent synthesis of pyrrole[2,3-b]indole and urea derivatives has been described. Pyrrole[2,3-b]indoles (“cyclization on” products) via tandem cyclization of o-alkynylanilines with isocyanides in the absence of a ligand and ureas (“cyclization off” products) via oxidative amination of anilines with isocyanides in the presence of
本文描述了用于吡咯[2,3- b ]吲哚和尿素衍生物的不同合成的钯催化和配体控制的方案。吡咯[2,3- b ]吲哚(“环化”产物)是在没有配体的情况下通过邻炔基苯胺与异氰化物的串联环化而生成的;脲(“环化”产物)是通过在存在配体的情况下苯胺与异氰化物的氧化胺化来生成的的配体均以中等至良好的收率和高选择性获得。在这种化学中,在配体的调节下,使用相同的起始材料很容易获得环状和非环状产物。