Mechanistic Studies of the Oxidative Addition of Aryl Halides to Ni(0) Centers Bearing Phosphine Ligands

Abstract

The oxidative addition of aryl halides is a common entry point in catalytic cycles for cross-coupling and related reactions. In the case of phosphine-supported nickel(0) fragments, the formation of reactive Ni(ii)–aryl products often competes with the production of Ni(i) species. Here, recent advances in the mechanistic understanding of these reactions are highlighted. In particular, the denticity of the supporting ligand has a significant influence on the outcome of the reaction.

A guide to secondary coordination sphere editing

“…Compounds of the type [Ni(diphosphine) 2 ] (where diphosphine is aryl or alkyl substituted) are often inert toward such reactivity, owing to unfavourable ring-opening that is required to generate a reactive intermediate k 1 -P diphosphine compound. [111][112][113][114][115][116] With the backdrop set, [Ni(P 2 B Cy4 modification, examples of which are known, and some of which are relevant to the preceding sections. [117][118][119] With interest in expanding the hydride donor toolbox, emphasis has turned to the development of compounds with strong hydride donor ability (DG H À).…”

Reactions of nickel(0) with organochlorides, organobromides, and organoiodides: mechanisms and structure/reactivity relationships

“…Some aspects of this topic were recently reviewed by Pérez-Garcí and Moret. 17 In 1970, Fahey reported the products of the reactions of [Ni(η 2 -C 2 H 4 )(PR 3 ) 2 ] (R = Et or Ph) with bromopentafluorobenzene, chlorotrifluoroethylene, 1,2,4trichlorobenzene, 1,2-dichlorobenzene, and 1-bromo-2chlorobenzene; 18 these were obtained in 6-19% yield and formulated as the trans-[Ni(X)(R′)(PR 3 ) 2 ] complexes based on infrared analysis which revealed a strong band at ca. 420 cm −1 that is proposed to correspond to an asymmetric Ni-P stretching vibration.…”

The Effect of Added Ligands on the Reactions of [Ni(COD)(dppf)] with Alkyl Halides: Halide Abstraction May Be Reversible

“…The reactions of alkyl halides with nickel(0) have received relatively little attention compared to reactions of aryl halides and other aryl electrophiles. − Baird has studied the reactions of various alkyl halides with [Ni­(PPh 3 ) 4 ] via variable temperature 1 H and 31 P NMR spectroscopic analyses of reactions in situ . The major products from the reactions of iodoalkanes are alkanes and alkenes, with a nickel hydride species obtained as a minor product; this suggests that formal oxidative addition was followed by β-hydride elimination.…”