Radical Carbonitrosation and Recycling of the Waste Gas Nitrogen Monoxide

Ruthenium‐Catalyzed Direct Transformation of Alkenyl Oximes to 5‐Cyanated Isoxazolines: A Cascade Approach Based on Non‐Stabilized Radical Intermediate

“…This result implies a radical pathway for this reaction and also supports the assumption that the C–N bond formation is not a fast process. [13a] Finally, when oxime 3 was treated with a ruthenium catalyst at room temperature, nitrile 2a was isolated in 95 % yield [Equation (4)]. This result implies that the oxime is probably the intermediate of this reaction and the function of the ruthenium catalyst may be converting the oxime intermediate to nitrile.…”

“…Along with the significant development of radical chemistry, radical reactions based on 1,2‐difunctionalization of alkenes and nitrogen‐centered radical scavengers or C–N bond formation with NO radicals, have emerged as the most powerful tools for the assembly of diverse useful molecules. Additionally, β,γ‐unsaturated ketoximes have been widely used to synthesize isoxazolines through radical cyclization strategy, since the isoxazoline skeleton is extensively found in molecules with biological activity, and can also act as versatile intermediates in organic synthesis .…”

Twofold Carbon–Carbon Bond Formation by Intra‐ and Intermolecular Radical Reactions of Aryl Diazonium Salts

“…Among these, sulfonyl azides27 and aryl diazonium salts20a,b,c,f have been intensively investigated over recent years. In this ongoing study we focused on the use of the very simple nitrogen‐centered radical scavenger nitrogen monoxide, which has recently given good results in iron(II)‐mediated Meerwein arylations with activated alkenes 20g. In these reactions, the iron(II) ions do not only serve as reductants to generate aryl radicals from diazonium salts, but they also increase the solubility of nitrogen monoxide, which allows an efficient trapping of radical intermediates.…”

Recent Advances in Meerwein Arylation Chemistry

“…37,43 By employing iron(II) sulfate for aryl radical generation from diazonium salts such as 16, a particular feature of iron(II) ions can be exploited, which is the formation of iron(II)-nitrosyl complexes in the presence of NO (Scheme 6). 44 In this way, the concentration of nitrogen monoxide in the reaction mixture can be significantly increased, and aryl radical attack on methyl acrylate (17) is then effectively followed by trapping with NO to give oxime 18 via a final tautomerization step. Further studies on this reaction type have shown that it can basically be used for the denitrification of waste gases, though at comparably high concentrations of more than 5 vol% NO.…”