Bidirectional Electron Transfer Strategies for Anti-Markovnikov Olefin Aminofunctionalization via Arylamine Radicals.

Arylamines are common structural motifs in pharmaceuticals, natural products, and materials precursors. While olefin aminofunctionalization chemistry can provide entry to arylamines, classical polar reactions typically afford Markovnikov products. Nitrogen-centered radical intermediates provide the opportunity to access anti-Markovnikov selectivity; however, anti-Markovnikov arylamination is unknown in large part due to the lack of arylamine radical precursors. Here, we introduce bidirectional electron transfer processes to generate arylamine radical intermediates from -pyridinium arylamines: Single-electron oxidation provides arylamine radicals that engage in anti-Markovnikov olefin aminopyridylation; single-electron reduction unveils arylamine radicals that engage in anti-Markovnikov olefin aminofunctionalization. The development of bidirectional redox processes complements classical design principles for radical precursors, which typically function via a single redox manifold. Demonstration of both oxidative and reductive mechanisms to generate arylamine radicals from a common -aminopyridinium precursor provides complementary methods to rapidly construct and diversify arylamine scaffolds from readily available radical precursors.