Advances and Applications in Catalysis with Earth-Abundant Metals

Abstract

RecommendationsT ransition-metal catalysis has revolutionized chemical synthesis, with the study and implementation of new metal complexes and reaction types ubiquitous in both academic and industrial settings.These intellectual contributions to transition-metal-catalyzed reactions have been acknowledged numerous times in the award of several Nobel Prizes: for example, Chauvin, Grubbs, and Schrock for their work on ruthenium and molybdenum metathesis; Noyori and Knowles for their work on rhodium and ruthenium enantioselective hydrogenations, shared with Sharpless for his work on chirally catalyzed oxidation reactions (including those mediated by osmium and titanium); Heck, Negishi, and Suzuki for their work on palladium catalyzed cross-couplings; and Sharpless and Meldal for copper-catalyzed "click" chemistry, awarded alongside Bertozzi for her development of bioorthogonal click chemistry.In industry, the potential of these catalytic transformations has been recognized and embraced: for example, commonly employed methods with precious metals are used for small-screening experiments through to manufacturing-scale campaigns. 1Palladium features heavily in carbonylative acylations as well as C-C, C-N and C-O bond formations, while rhodium, ruthenium, and platinum appear in hydrogenations�both heterogeneous and asymmetric homogeneous versions. 2 Despite the widespread application of precious-metal catalysts, chemists cannot rely on them as a universal solution to unmet challenges in biology, chemistry, materials science, and beyond.Considering the low natural abundance and environmental impact of extracting these precious metals, factors including sustainability, cost, and price volatility are significant drivers to explore and further develop catalysts based on alternative elements. 3Additional concerns arise when evaluating the scope of reactions that are accessible via precious-metal catalysts.The strong preference for twoelectron transformations enforces predictable reactivity patterns but also limits scope.Earth-abundant element (EAE) catalysis is an emerging area of chemical research that addresses these issues.Identifying and applying catalysis with earth-abundant elements allows chemists to directly address the sustainability concerns surrounding precious metals.Additionally, moving away from precious metals brings with it new reactivity, enabling disconnections for which those catalysts are not efficient or in many cases are incapable of performing.These include sp 2 -sp 3 and sp 3 -sp 3 cross-couplings as well as photocatalytic and electrocatalytic transformations in which catalysts capable of engaging in single-electron transformations are more frequently used. 4,

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