Synthetic Diversity from a Versatile and Radical Nitrating Reagent

Abstract

We leverage the slow liberation of nitrogen dioxide from a newly discovered, inexpensive succinimide‐derived reagent to allow for the C−H diversification of alkenes and alkynes. Beyond furnishing a library of aryl β‐nitroalkenes, this reagent provides unparalleled access to β‐nitrohydrins and β‐nitroethers. Detailed mechanistic studies strongly suggest that a mesolytic N−N bond fragmentation liberates a nitryl radical. Using in situ photo‐sensitized, electron paramagnetic resonance spectroscopy, we observed direct evidence of a nitryl radical in solution by nitrone spin‐trapping. To further exhibit versatility of N‐nitrosuccinimide under photoredox conditions, the late‐stage diversification of an extensive number of C−H partners to prepare isoxazolines and isoxazoles is presented. This approach allows for the formation of an in situ nitrile oxide from a ketone partner, the presence of which is detected by the formation of the corresponding furoxan when conducted in the absence of a dipolarophile. This 1,3‐dipolar cycloaddition with nitrile oxides and alkenes or alkynes proceeds in a single‐operational step using a mild, regioselective, and general protocol with broad chemoselectivity.

Application of [PVI-SO3H]NO3 as a novel polymeric nitrating agent with ionic tags in preparation of high-energetic materials

“…10,11 Architecture of novel renewable and sustainable nitrating reagent in the organic transformation has attracted much attention in the science and industry because of their unique properties, such as efficiency, reusability, reactivity, stability, selectivity, generality and easy separation of the catalyst. [12][13][14][15][16][17][18] These methods of preparation of energetic materials were previously reported in the presence of some various nitrating agents, co-catalysts, and solvents, mixed acid of concentrated nitric acid and sulfuric acid, high temperature, long reaction times, and low yields [19][20][21][22][23][24][25][26][27][28][29][30] (Scheme 1).…”

Recent Advances in the Nitration of Olefins

“…[51][52][53][54] Katayev and co-workers in 2019 designed and developed a practical and bench-stable succinimide derived NO 2 -transfer reagent can liberate nitryl radical under mild and neutral conditions, thus allowing for the direct nitration of C(sp 2 )À H bonds of alkenes (Scheme 22). [55] This protocol also allows to access valuable nitrohydrin building blocks and functionalised isoxazole-motifs in an unprecedented and selective fashion using a single reagent in one-step. The reaction setup for this nitration protocol involves irradiation of 2.0 equivalents of Nnitrosuccinimide and 2.5 mol% of commercially available [Ru(bpy) 3 ](PF 6 ) 2 in MeCN with 350 W blue light for 6 h. This protocol affords the desired β-nitroalkene product with E-stereoselectivity along with good to excellent yields.…”

On the use of differential scanning calorimetry for thermal hazard assessment of new chemistry: Avoiding explosive mistakes

“…Similarly, novel radical nitrating reagent, N-nitrosuccinimide 3 (Figure 5e), was developed to transfer NO2 to alkenes, or form isoxazolines and isoxazoles from alkenes and alkynes respectively through photolytic formation of a nitryl radical species. [24] Reagent 3 was selected over N-nitropyrrolidinone 4 and N-nitrophthalimide, among other reasons, for a preferable thermal decomposition profile evidenced by an STA plot. For two of these compounds, the DSC heat flow plots alongside steady mass loss in the TGA suggest concurrent exothermic decomposition and endothermic evaporation or gas loss events (inferred from the chemical structure as gas evolution appears feasible) as would be expected in the open crucibles used in STA.…”