Recent advances in base metal-catalyzed cooperative transfer hydrogenation and hydrodeuteration of alkenes

Catalytic alkene hydrogenation is a powerful method that has been widely used in the syntheses of valu-able products ranging from commodity chemicals to pharmaceuticals. Hydrogenation has also been a key strategy for selectively introducing heavy hydrogen isotopes to small molecules, a key strategy for meta-bolism studies and even the synthesis of "heavy drugs," where the hydrogen isotope is a key element of the active pharmaceutical ingredient. Traditional hydrogenations with pressurized H2 gas are atom eco-nomic but often require complex reaction setups or expensive metal catalysts. Further, use of diatomic hydrogen necessarily limits the ability to incorporate different hydrogen isotopes at each alkene position, with H2, D2, and T2 each resulting in compete labeling of the alkene. In response to these challenges, a recent and growing movement has sought to develop transfer hydrogenation methods using non-H2 hydrogen sources and earth abundant element catalysts to simplify reaction operation. Excitingly, recent developments have delivered transfer hydrogenations that proceed using cooperative hydrogen donor reagents, permitting the controllable incorporation of different hydrogen isotopes at each position of the alkene via reagent control. In this Digest, we disclose recent advances in Earth-abundant metal -cat-alyzed cooperative transfer hydrogenation of alkenes with various combinations of two distinct transfer hydrogen reagents as non-H2 hydrogen sources.(c) 2023 Elsevier Ltd. All rights reserved.