Cobalt‐Catalyzed Radical Hydroamination of Alkenes with N‐Fluorobenzenesulfonimides

Abstract

AbstractAn efficient and general radical hydroamination of alkenes using Co(salen) as catalyst, N‐fluorobenzenesulfonimide (NFSI) and its analogues as both nitrogen source and oxidant was successfully disclosed. A variety of alkenes, including aliphatic alkenes, styrenes, α, β‐unsaturated esters, amides, acids, as well as enones, were all compatible to provide desired amination products. Mechanistic experiments suggest that the reaction underwent a metal‐hydride‐mediated hydrogen atom transfer (HAT) with alkene, followed by a pivotal catalyst controlled SN2‐like pathway between in situ generated organocobalt(IV) species and nitrogen‐based nucleophiles. Moreover, by virtue of modified chiral cobalt(II)‐salen catalyst, an unprecedented asymmetric version was also achieved with good to excellent level of enantiocontrol. This novel asymmetric radical C−N bond construction opens a new door for the challenging asymmetric radical hydrofunctionalization.