Nitrosonium reagents preparation

Nitrosonium tetrafluoroborate has been prepared from nitrosyl fluoride (NOF) and boron trifluoride in Freon-113. With this reagent, in a nitro-methane solution, pyridine was converted into jV-nitrosopyridinium tetra-fluorobate, m.p. 155°-158°C [33]. 

Regeneration of carbonyl compounds from 1,3-dithian 1-oxides can be accomplished using triethyloxonium tetrafluoroborate. Nitrosonium salts, and nitronium salts, either preformed or prepared in situ, are effective reagents for the cleavage of dithioacetals. Similarly hydrolysis of thioacetals can be performed with thallium trinitrate, and selective hydrolysis can also be achieved with this reagent [equation (59)]. ... 

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