Jack I. Mansell, Ciro Romano, David J. Procter
Abstract The strategies adopted in the development of Sm II ‐catalyzed processes are critically evaluated. In particular, we examine promising approaches using stoichiometric sacrificial reductants, electrochemical methods, photochemical processes, and electron recycling through back electron transfer to Sm. While each strategy has considerable potential for facilitating catalytic Sm II transformations, they also face specific challenges relating to efficiency, selectivity, scalability, and generality. We highlight the strengths and limitations of each approach, discuss recent advances, and identify challenges that remain. By offering an in‐depth analysis of the current state‐of‐the‐art in Sm II catalysis, we aim to guide future research to complete the reinvention of SmI 2 as a tool for sustainable catalysis.