Copper-Catalyzed Reductive Hydroamination of Alkenes and 1,3-Dienes with Nitroarenes

In this study, copper-catalyzed reductive hydroamination of alkenes and 1,3-dienes with nitroarenes was developed. Such umpolung hydroamination of unsaturated C═C double bonds exhibited Markovnikov selectivity, and the hydroamination of 1,3-dienes preferred 1,2-addition. Mechanistic studies suggested the system proceeds through a radical pathway with the concomitant activation of both substrates to nucleophilic alkyl radical species and electrophilic nitro-based intermediates, respectively. The attack of alkyl radical species on the N atom of nitro-based intermediates yielded the desired amines. However, this C-N cross-coupling strongly competed with the self-reduction of each species under such a system.