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N- functionalized aziridines, which are both useful intermediates and important synthetic targets, can be envisioned as arising from the addition of nitrenes ( i.e ., NR fragments) to olefinic substrates. The exceptional reactivity of most nitrenes, in particular with respect to unimolecular decomposition, prevents general application of nitrene-transfer to the synthesis of N -functionalized aziridines. Here we demonstrate N -aryl aziridine synthesis via 1) olefin aziridination with N -aminopyridinium reagents to afford N -pyridinium aziridines followed by 2) Ni-catalyzed C–N cross-coupling of the N -pyridinium aziridines with aryl boronic acids. The N -pyridinium aziridine intermediates also participate in ring-opening chemistry with a variety of nucleophiles to afford 1,2-aminofunctionalization products. Mechanistic investigations indicate aziridine cross-coupling proceeds via a noncanonical mechanism involving initial aziridine opening promoted by the bromide counterion of the Ni catalyst, C–N cross-coupling, and finally aziridine reclosure. Together, these results provide new opportunities to achieve selective incorporation of generic aryl nitrene equivalents in organic molecules. Aziridines are useful intermediates, present in important synthetic targets. Here, the authors show a strategy for the synthesis of N-aryl aziridines based on N-aminopyridinium reagents followed by Ni-catalyzed C–N cross-coupling of N-pyridinium aziridines with aryl boronic acids.

The dianionic cluster [Os 10 (µ 6 -C)(CO) 24 ] 2− reacts with excess SbX 3 or p -tolylSbX 2 to form the monoanionic clusters [Os 10 {µ 4 -Sb( p -tolyl) n X 2-n }(µ 6 -C)(CO) 24 ] − (n = 0; X = Cl, I; n = 1, X = Cl) via insertion into an Os–Os bond. Further insertion into an Os–Os bond occurs when they are reacted further with excess iodine. The chemistry and structure of these clusters can be understood in terms of the isolobal analogy between [Sb( p -tolyl) n X 2-n )] + and I + .

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 lack of arylamine radical precursors. Here, we introduce bidirectional electron transfer processes to generate arylamine radical intermediates from N-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. Demonstration of both oxidative and reductive mechanisms to generate arylamine radicals from a common N-aminopyridinium precursor provides new methods to rapidly construct and diversify arylamine scaffolds from readily available radical precursors.