Parameterization of phosphine ligands demonstrates enhancement of nickel catalysis via remote steric effects

Abstract

The field of Ni-catalysed cross-coupling has seen rapid recent growth because of the low cost of Ni, its earth abundance, and its ability to promote unique cross-coupling reactions. Whereas advances in the related field of Pd-catalysed cross-coupling have been driven by ligand design, the development of ligands specifically for Ni has received minimal attention. Here, we disclose a class of phosphines that enable the Ni-catalysed Csp3 Suzuki coupling of acetals with boronic acids to generate benzylic ethers, a reaction that failed with known ligands for Ni and designer phosphines for Pd. Using parameters to quantify phosphine steric and electronic properties together with regression statistical analysis, we identify a model for ligand success. The study suggests that effective phosphines feature remote steric hindrance, a concept that could guide future ligand design tailored to Ni. Our analysis also reveals that two classic descriptors for ligand steric environment—cone angle and % buried volume—are not equivalent, despite their treatment in the literature.

Ligand–Substrate Dispersion Facilitates the Copper-Catalyzed Hydroamination of Unactivated Olefins

“…20–23 To date, it remains a significant challenge to quantitatively describe the catalyst-substrate dispersion interaction and distinguish it from other types of non-covalent interactions, such as steric and electrostatic effects. 24–26 Inspired by the distortion/interaction model established by Houk and Bickelhaupt, 27 herein we report a ligand-substrate interaction model for the analysis of ligand effects on the through-space and through-bond interactions between the catalyst and the substrate. Based on energy decomposition analysis 28,29 of computed transition states, this model allows for the quantitative prediction of the effects of ligand-substrate dispersion interactions on catalyst’s activity.…”

Quantitative Modeling of Bis(pyridine)silver(I) Permanganate Oxidation of Hydantoin Derivatives: Guidelines for Predicting the Site of Oxidation in Complex Substrates

“…Previous studies from one of our groups 23 and others 24 have identified numerous multi-dimensional correlations between molecular parameters and reaction outcomes. The computationally derived parameters in this study only revealed relatively complex models to describe the rate measurement, the simplest of which involved four unique terms.…”

Thorpe–Ingold Effect in Branch‐Selective Alkylation of Unactivated Aryl Fluorides

“…In contrast, the P-Ni-P angle did not lead to acorrelation on the selectivity and yields,thus reinforcing the validity of the gem-dialkyl effect. [19] As depicted in Figure 3, av ariety of electronically unbiased Grignard reagents were accommodated. Finally,inascreening for additives,CsF was found to aid in preventing further isomerization.…”