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Bisphosphine‐Ligated Nickel Pre‐catalysts in C( sp 2 )–N Cross‐Couplings of Aryl Chlorides: A Comparison of Nickel(I) and Nickel(II)
Author(s) -
Lavoie Christopher M.,
McDonald Robert,
Johnson Erin R.,
Stradiotto Mark
Publication year - 2017
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201700672
Subject(s) - nickel , chemistry , catalysis , aryl , oxidative addition , limiting , reductive elimination , ligand (biochemistry) , medicinal chemistry , inorganic chemistry , organic chemistry , mechanical engineering , biochemistry , alkyl , receptor , engineering
The influence of ancillary ligand and nickel oxidation state in the nickel‐catalyzed C( sp 2 )–N cross‐coupling of aryl chlorides is examined by use of experimental and DFT methods for the first time, focusing on ( L )NiCl and ( L )Ni( o ‐tolyl)Cl pre‐catalysts (PAd‐DalPhos, L1 ; dppf, L2 ). Whereas Ni(II) pre‐catalysts generally out‐performed Ni(I) species in our study, the viability and in some cases superiority of Ni(I) pre‐catalysts in challenging aminations is established. Computational analyses support the viability of Ni(0)/Ni(II) cycles featuring rate‐limiting C–N reductive elimination, as well as parallel Ni(I)/Ni(III) mechanisms involving rate‐limiting C–Cl oxidative addition.