Synthesis of Symmetrical Bisquinolones via Nickel(0)‐Catalyzed Homocoupling of 4‐Chloroquinolones

Abstract

A method for the gram-scale preparation of functionalized 4,4'-bisquinolones using a microwave-assisted Ullmann-type homocoupling reaction is described. The method is catalytic in nickel(0) which is generated in situ by reduction from an inexpensive nickel(II) source and utilizes readily available 4-chloroquinolin-2(1H)-ones as starting materials. In contrast to the alternative palladium(0)-catalyzed one-pot borylation/Suzuki crosscoupling reaction, the new method avoids the use of an expensive catalyst and cross-coupling partner such as bis(pinacolato)diboron.

Nickel-Catalyzed Cross-Couplings Involving Carbon−Oxygen Bonds

“…Kappe later explored a similar strategy for the synthesis of aza-analogues of biscoumarins 152,153. The compatibility of this catalytic system with tosylates, brings into question the involvement of halide-bridged intermediate (Scheme 35), though it is technically possible that the use of NaI as additive may facilitate the formation of this intermediate through displacement chemistry.…”

New catalyst for homocoupling of aryl halides based on nickel complexes with diazabutadiene ligands

“…Yield 3.89 g (78%), dark-yellow crystals. 1 Н NMR spectrum (CDCl 3 ), δ, ppm: 0.97 d (12H CH 3 , J 6.9 Hz), 1.24 d (12H, CH 3 , J 6.9 Hz), 3.04 heptet (4H, CH, J 6.8 Hz), 6 1 Н, 13 С NMR spectra were registered on a spectrometer Bruker Avance 400 DPX at operating frequencies 400 and 100 MHz respectively. Chemical shifts are reported with respect to TMS signal.…”

“…As known, in the homocoupling are used not only complexes with phosphine ligands, but also with bipyridyl ligands [1,2,[4][5][6][7]. We found besides that the catalyst based on о-phenanthroline also exhibited a moderate activity in homocoupling of bromobenzene.…”

Poly(vinylpyridine)‐Grafted Silica Containing Palladium or Nickel Nanoparticles as Heterogeneous Catalysts for the Sonogashira Coupling Reaction

“…[15,[31][32][33] Nickel is a promising and cheaper alternative to the use of palladium as a transition-metal catalyst in coupling reactions. There are many reports in the literature on the use of nickel as an alternative to palladium in homocoupling [34][35][36] and crosscoupling reactions such as Heck, Suzuki, and Kumada, [37][38][39][40][41][42][43] but there are only a few reports on Ni-catalyzed Sonogashira reactions. [22][23][24][25][26][27][28] A nickel-catalyzed Sonogashira reaction was reported by Beletskaya et al using homogeneous Ni II species.…”