Efficient, Nickel‐Catalysed Kumada–Tamao–Corriu Cross‐ Coupling with a Calix[4]arene‐Diphosphine Ligand

The dynamic complex cis ‐ P,P ′‐(η 5 ‐cyclopentadienyl)‐{5,17‐bis(diphenylphosphino)‐25,26,27, 28‐tetrabenzyloxycalix[4]arene}nickel(II) tetrafluoroborate ( 2 ) in which the PNiP plane undergoes a rapid fanning motion was assessed in the cross‐coupling reacting between phenylmagnesium bromide (PhMgBr) and aryl halides (ArX). TOFs, of up to 21250 mol(converted ArBr)⋅mol( 2 ) −1 ⋅h −1 , were obtained with electron‐rich as well as congested bromoarenes using catalyst loadings as low as 1×10 −3  mol%, provided that the reactions were carried out at 100 °C in dioxane with a PhMgBr/ArX ratio of 2:1. The high activities observed contrast with those observed for triphenylphosphine‐based catalysts and furthermore, outperforms the fastest diphosphine‐based catalysts reported, a behaviour which is likely to rely on a bite angle effect.