Nitrito onium ion

The unique hydride abstraction property has been gainfully employed in developing novel synthetic reactions.530 Reactive hydrocarbons such as triphenylmethane, adamantane, and diamantane are readily fluorinated in the presence of nitrosonium ion in HF-pyridine media.537 In the presence of a suitable oxygen donor such as dimethyl sulfoxide, the nitrosonium ion can act as a nitrating agent538 [Eq. (4.152)]. The initially formed nitrito onium ion 223 transfer nitrates aromatics rather readily.245 The NO+-induced reactions are further reviewed in Chapter 5. 

Recently Olah and associates [91], [40c] obtained 5- and /V-nitrito onium ion salts (31) and (32), and found them to be electrophilic nitrating agents ... 

There has been much interest in the reactivity of nitronium salts, for example, toward amides in acetonitrile,the oxidation of alkanes in acetonitrile (via a carbenium ion intermediate),and toward organic sulfides, phosphines, arsines, and stibines. Reaction with diaryl, aryl alkyl, and dialkyl sulfides give sulfoxides, but a few percent of the ring C-nitro products were found for diphenyl sulfide. This is a result of the equilibrium between nitrito onium ions ] X-ONO and nitronium ions This is the first demonstration of the ambident reactivity... 

V-Nitrito-4-nitropyridinium salts are isomeric with the previously discussed W-nitropyridinium ions. Similarly, dimethylnitritosulfonium salts are isomeric with IV-nitrosulfonium ions, formed from nitronium salts and dimethyl sulfide. The nitro-onium salts are prepared from nitrosonium hexafluorophosphate with 4-nitropyridine-/V-oxide and dimethyl sulfoxide, respectively [131]. 

---