Metal-Hydride Hydrogen Atom Transfer: A Decade of Advances in Selective Alkene Functionalization and Asymmetric...

Metal-hydride hydrogen atom transfer (MHAT) catalysis has emerged as a powerful platform for the selective functionalization of alkenes via carbon-centered radical intermediates. By facilitating outer-sphere hydrogen atom transfer, MHAT circumvents the limitations of classical coordination-insertion pathways and affords direct access to reactive radical species from simple alkene feedstocks. Over the past decade, this chemistry has expanded from reductive hydrogenation to a broad range of hydrofunctionalization protocols, including C─O, C─N, and C─C bond-forming reactions. Central to these advances is the increasing ability to control the subsequent reactivity of alkene-derived radicals, enabling transformations through radical addition, radical-polar crossover, radical-radical coupling, and metal-mediated cross-coupling pathways. Furthermore, merging MHAT with photoredox, electrochemical, and dual catalytic systems has expanded its scope and versatility. Despite these advances, significant challenges persist in achieving precise stereocontrol and broadly applicable enantioselective transformations. This Review summarizes developments in MHAT catalysis from 2014 to 2025, with particular emphasis on mechanistic principles and emerging strategies for selective alkene functionalization.