Enabling Unfavorable\nHydroamination Reactions Using\na Chemoselective N–O Bond Reduction

Despite major advances, intramolecular alkene hydroamination\nreactions\noften face limitations. Herein, a redox-enabled process featuring\noxidation of an amine to a hydroxylamine, a concerted hydroamination\nstep, followed by catalytic reduction of <i>N</i>-oxide\nis shown to be broadly applicable. Catalyst screening and optimization\nshowed that a K<sub>2</sub>OsO<sub>2</sub>(OH)<sub>4</sub>–pinacol\ncomplex rapidly and chemoselectively reduces the <i>N</i>-oxide cycloadduct in the presence of hydroxylamine and dimethyl\nsulfoxide. This selectivity was exploited to drive the equilibria\ntoward complex products.