| Description |
A critically important process in catalysis is the formation of an active catalyst from the combination of a metal precursor and a ligand, as the efficacy of this reaction governs the amount of active catalyst. This review is a compacted but comprehensive review of reactions catalyzed by nickel and an added bidentate phosphine, specifically in regards to cross-coupling reactions, a large enough sample pool to still elucidate information over this catalytic process. The highlight in the review is the steps of transformation and the combination of precatalyst and ligand into an active catalyst and the potential effects of this transformation on nickel catalysis. Overall the most widely used nickel precatalyst with free bidentate phosphines is Ni(cod)2, followed by Ni(acac)2 and Ni(OAc)2. By compiling the reports surveyed, we have calculated statistics of the usage and efficacy of each ligand with Ni(cod)2 and other nickel sources. The most common bidentate phosphines are simple, relatively inexpensive ligands, such as DPPE, DCPE, DPPP, and DPPB, along with more complex backbones, such as DPPF and Xantphos. The use of expensive chiral phosphines is more scattered, but the most common ligands include BINAP, Me-Duphos, Josiphos, and related analogs. Covering this range of ligands is to not only screen the efficacy of the ligands themselves, but push the worthwhile efficacy in nickel catalysis itself, as an option for a far more affordable and accessible catalytic approach than some of the most currently popular alternatives. This thesis is an excerpt of the complete published review, in order to concisely show the analysis of trends. Specifically, it investigates hydrogenation, due to its place as a kind of median between commonality and interesting results in the review as a whole. |
