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We’re Going to Need Abiggerphos

Bulky phosphines from Abigail Doyle’s lab enable more effective Ni-catalyzed cross coupling reactions through remote steric hindrance

The field of cross-coupling catalysis using palladium has seen tremendous growth over the years, with a wide variety of reactions developed and a correspondingly large number of ligands which accommodate these reactions. By contrast, the field of nickel catalysis has grown at a much slower rate. This slower growth is exacerbated by the fact that the majority of ligands developed for cross-coupling were created for use with palladium and are often ill-suited for catalysis with Ni. In response to the lack of available ligands for nickel catalysis, Abigail Doyle’s group at Princeton University has been working to develop novel ligands specifically suited for this purpose: In a seminal publication in Nature Chemistry, they describe the development of a cross coupling reaction between acetals and boronic acids. One high-performing ligand which emerged from this study is the CyTyrannoPhos ligand (Strem# 15-8250) (Figure 1).


One of the key findings of this work is the conclusion that the cone angle of a ligand does not always correlate with its percent buried volume in terms of catalytic performance (Figure 2). This has especially profound consequences for Ni compared to Pd due to its significantly smaller atomic radius: bulky ligands which allow for reactivity at a Pd center may instead completely bury a Ni atom and prevent catalyst–substrate interaction. If this steric bulk is instead placed farther away from the metal center (as it is in CyTyrannoPhos), reactivity at Ni is preserved and, in some cases, can even outperform Pd catalysis. Taking advantage of this “remote steric hindrance” has allowed the Doyle group to develop a uniquely competent catalytic system using Ni. Understanding that the parameters used to evaluate second and third row transition metal catalyst may not always correlate with their first-row counterparts is critical to the development of novel and highly effective catalytic systems based on first row metals.


Figure 2. Illustration defining percent buried volume and cone angle, and how these two parameters factor into remote steric hindrance (Figure reproduced from reference 1).

Strem offers CyTyrannoPhos (Strem# 15-8250) in research quantities.



  1.       Nat. Chem. 2017, 9, 779-784.


Featured Product:

15-8250 Bis(3,5-di-tert-butylphenyl)cyclohexylphosphine, min. 98% CyTyrannoPhos (2097604-67-4)

Related Product Lines:

Ligands & Chiral Ligands
Phosphorus Ligands & Compounds



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