Catalysis on a Knife's Edge: Detailed Mechanistic Studies Reveal a Fine Balance Between Catalyst Deactivation and Productive Reactivity in CuH-Catalyzed Alkene Hydrofunctionalization.

Copper hydride catalyst systems have been widely applied to the hydrofunctionalization of unsaturated compounds, enabling the synthesis of a range of valuable organic products. In particular, copper catalysts supported by bulky bisphosphine ligands such as DTBM-SEGPHOS have enjoyed noteworthy success across a range of substrate classes, with the highly unstable monomeric LCuH (L = DTBM-SEGPHOS) often implicated as the active form of the catalyst. Recently, Ryan et al. Angewandte Chemie Novit 2, no. 2 (2026): e70025 have not only characterized the elusive monomeric LCuH, but have provided a suite of kinetic and computational experiments that reveal the mechanisms by which these catalysts form inactive higher order Cu aggregates. Collectively, these important studies substantially increase knowledge of LCuH speciation and the factors that control the relative rates between productive alkene hydrocupration and catalyst deactivation-insights which are anticipated to inform the design of next-generation catalysts.