Protonation of diazodiketones N₂C(COR)₂ in Brønsted superacids (TfOH, FSO₃H, TfOH–SbF₅) gives rise to stable and non-reactive O,O-diprotonated at carbonyl oxygens species N₂C(C(OH⁺)R)₂, which were studied by means of ¹H and ¹³C NMR. Diazomalonates N₂C(CO₂Alk)₂, contrary to diazodiketones, react with TfOH or HF, releasing nitrogen and producing triflates of oxymalonates TfOCH(CO₂Alk)₂ or fluoromalonates FCH(CO₂Alk)₂, respectively. Diazoketoesters N₂C(COR)(CO₂Alk) react in the same way only with TfOH, but not with HF. The reactions of diazomalonates with arenes ArH (benzene, toluene, xylenes) in TfOH solution yield corresponding Friedel–Crafts reaction products ArCH(CO₂Alk)₂. According to performed DFT calculations, trication ⁺CH(C(OH⁺)OMe)₂, a possible intermediate, which is derived from protonation of dimethyl diazomalonate, should be the strongest cationic carbon-centered electrophile known up to date.

中文翻译：

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α-重氮-β-二羰基化合物在超酸中的质子化和转化：在Friedel-Crafts反应中重氮丙二酸酯的质子化过程中生成最强的以碳为中心的阳离子亲电试剂

在Brønsted超强酸（TfOH，FSO ₃ H，TfOH–SbF ₅）中重氮二酮N ₂ C（COR）_2的质子化作用会生成在羰基氧物种N ₂ C（C（OH ⁺）R）₂，其通过¹ H和¹³ C NMR研究。与重氮二酮相反，重氮丙二酸酯N ₂ C（CO ₂ Alk）₂与TfOH或HF反应，释放氮并生成三氟甲磺酸酯TfOCH（CO ₂ Alk）₂或氟丙二酸酯FCH（CO ₂ Alk）₂， 分别。重氮酮酸酯N ₂ C（COR）（CO ₂ Alk）仅以相同的方式与TfOH反应，而不与HF反应。重氮丙二酸酯与芳烃ArH（苯，甲苯，二甲苯）在TfOH溶液中的反应产生相应的Friedel-Crafts反应产物ArCH（CO ₂ Alk）₂。根据进行的DFT计算，由重氮丙二酸二甲酯的质子化衍生而来的可能的中间体三阳离子⁺ CH（C（OH ⁺）OMe）₂应该是迄今为止已知的最强的阳离子碳中心亲电体。