Nickel-Catalyzed Intramolecular 1,2-Addition Reaction Of Aryl(Vinyl) Halides

Transition metal-catalyzed 1,2-addition reaction of organohalide to carbon-heteroatom multibond effectively avoids the preparation of active organometallic reagent, simplifies the synthetic process and improves scope of the substrate bearing different functional groups. Therefore, it attracts more and more attention. Here, nickel-catalyzed intramolecular additon of aryl(vinyl) halide to ketones and epoxides has been developed.1. Direct intramolecular 1,2-addition of aryl(vinyl) halide to ketones was carry out in the presence of Ni(Ⅱ)/Zn system. By optimization of ligand, solvent, and others, optimal reaction conditions were established as followings:10 mol% Ni(bpy)Br2 as catalyst and 2.5 eq. zinc powder as reducing agent in THF/CH3CN (7/1) at 75℃. Under the above optimal conditions, pyrrolidones (76-96% yields),3-hydroxyoxindoles (90-98% yields), and dihydroquinolinones (72-76% yields) were afforded.2. Nucleophilic ring-opening of epoxides in the presence of Ni(Ⅱ)/Zn was invetigated. The choice of base, solvent, and ligand were crucial to the ring-opening reaction. The optimized condition was established as followings:Ni(dppe)Br2 (10 mmol%), Zn (2.5 eq.), triethylamine (2 eq.), 4A MS,1,4-dioxane as solvent at 75℃. The desired product 3-benzyl-3-hydroxyoxindoles were obtained in 53-80% yields under the optimal reaction conditions.