Condensation of organic bromides with vinyl compounds catalysed by nickel complexes in the presence of zinc

NiCl2·6H2O: an efficient catalyst precursor for phosphine-free Heck and Sonogashira cross-coupling reactions

“…The results of this investigation demonstrated that an increase in the catalyst loading led to increasing of the yields. Using 20 mol% of NiCl 2 .6H 2 O, aryl bromides containing electronwithdrawing and electron-donating groups were coupled with styrene and n-butylacrylate to furnish the corresponding products in excellent yields (80-91% yield, Table 2, entries 8-10 and [17][18][19]. The Heck reaction of sterically hindered 1-bromonaphthalene afforded moderate yields of the corresponding coupled products with styrene and n-butylacrylate ( Table 2, entries 11 and 20).…”

“…The earlier attempts to use Ni(II) complexes such as NiCl 2 (PPh 3 ) 2 to catalyze the coupling between activated olefins (e.g. ethyl acrylate) and aryl halides were moderately successful [16][17][18][19][20], in which mixtures of the addition and substitution products were obtained resulting in poor selectivity for the vinylation. In addition, stoichiometric amounts of a reductant such as Zn dust were required in the reaction to ensure the catalytic effect.…”

Nickel-Catalyzed Reductive Couplings

“…On the other hand, the addition of aryl and vinyl halides with acrylates and styrenes in the presence of (PPh 3 ) 2 NiCl 2 (cat. )/Zn/pyridine effectively generates Heck-type products [106]. In 2010, Cheng expanded this strategy to the reductive condensation of aryl halides with conjugated alkynes in the presence of an orthoamine or amide group (Scheme 41, top) [107,108].…”

Nickel‐Catalyzed Mizoroki–Heck‐Type Reactions of Unactivated Alkyl Bromides

“…Despite the development of a number of intermolecular alkyl-Mizoroki-Heck-type cross-couplings using palladium catalysis, [9] there are no general nickel-catalyzed variants available. [10,11] We examined the cross-coupling of several alkyl bromides and alkene coupling partners (Table 3). Aryl-substituted acyclic bromide 26 delivered alkyl-Mizoroki-Heck-type products 27 and 28 in moderate yields in reactions with acrylonitrile and methyl acrylate, respectively (entries 1–2).…”