N‐Heterocyclic Carbenes: Useful Ligands for the Palladium‐Catalysed Direct C5 Arylation of Heteroaromatics with Aryl Bromides or Electron‐Deficient Aryl Chlorides
Pd-N-heterocyclic carbene complexes have been prepared and employed for palladium-catalysed directarylation of heteroaromatic derivatives by using aryl halides. These catalyst precursors promote the coupling of challenging aryl halides such as deactivated or congested arylbromides and also activated aryl chlorides. This procedure employs only 1 mol-% of an air-stable palladium complex. This is a
Congested Ferrocenyl Polyphosphanes Bearing Electron-Donating or Electron-Withdrawing Phosphanyl Groups: Assessment of Metallocene Conformation from NMR Spin Couplings and Use in Palladium-Catalyzed Chloroarenes Activation
4-chloropropiophenone, and 4-(trifluoromethyl)chlorobenzene were efficiently coupled to n-butyl furan, using Pd(OAc)2 associated to the new diphosphane ligands 1,1′-bis(diisopropylphosphanyl)-3,3′-di(triphenyl)methyl ferrocene (15) or 1,1′-bis(dicyclohexylphosphanyl)-3,3′-di(triphenyl)methylferrocene (16), which respectively hold the electron-rich −Pi-Pr2 and −PCy2 groups.