Multiple Deuterium Atom Transfer Perdeuteration of Unactivated Alkenes under Base‐Assisted Cobalt/Photoredox Dual Catalysis

A radical approach for hydrogenative perdeuteration of unactivated alkenes under cobalt/photoredox dual catalysis is described. The addition of a suitable base plays a key role in controlling two competing pathways by switching the catalytic performance of cobalt/photoredox catalysis. Base-assisted cobalt/photoredox dual catalysis promoted a hydrogen isotope exchange reaction of alkenes to afford deuterated alkenes via multiple repeating deuterium atom transfer/hydrogen atom abstraction processes, while consecutive reductive deuteration of alkenes proceeded in the absence of a base to afford polydeuterated alkanes. One-pot hydrogenative perdeuteration and perdeutero-arylation were also developed, providing access to various polydeuterated aliphatic compounds.