Photoredox-Catalyzed Decarboxylative Nitro-Mannich Reaction

β-Nitroamines are privileged synthetic motifs featuring vicinal nitrogen centers in distinct oxidation states. Here, we report a photoredox-catalyzed, decarboxylative nitro-Mannich reaction for the synthesis of skeletally diverse β-nitroamines using readily accessible gem-bromonitroalkanes. In addition, substituted β-amino esters were also accessed. This operationally simple protocol proceeds under mild conditions and obviates the need for preactivation of carboxylic acids. Mechanistic studies suggest that sequential radical decarboxylation, putative halogen-atom transfer (XAT), and reductive radical-polar crossover result in umpolung of reactant electronics, enabling transition metal-free C(sp³)-C(sp³) bond formation.