Nitryl fluoroborate

Nitration of 1,2-dialkylvinyl azides with nitryl fluoroborate yields l-azido-2-nitroalkene (110), which spontaneously decomposes with loss of nitrogen to the dialkylfuroxan. Compound (110) is also formed on treatment of 1,2-dinitroalkenes with azide ion and from ... 

The following procedure is available if elemental fluorine cannot be used stoichiometric quantities of anhydrous HFand BF3 are added to a solution of in nitromethane. Nitryl fluoroborate precipitates out of the nitromethane solution. The crystals are filtered with exclusion of moisture and then heated with NaF to 240°C in a platinum or nickel vessel, analogous to procedure 1 in the preparation of NOF (p. 184). 

Nitryl fluoroborate 1,2-Nitroacylamines from ethylene derivs. and nitriles Extended Ritter reaction... 

A soln. of nitryl fluoroborate in anhydrous acetonitrile stirred and treated at -25° under Ng with propylene, then water added, and stirred with gradual warming to room temp, under N, l-nitro-2-acetamidopropane. Y 50%. F. e. s. M. L. Scheinbaum and M. Dines, J. Org. Chem. 36, 3641 (1971). 

Nitryl fluoroborate Ring closures with enazides... 

Fliroxans. An ethereal soln. of nitryl fluoroborate added dropwise at -10° under helium to the startg. vinyl azide in ether, allowed to warm to room temp., stirred, and the product isolated after 18 hrs. 3,4-dimethyl-l,2,5-oxadiazole 2-oxide. Y 83%. F. e. s. A. N. Thakore, J. Buchshriber, and A. C. Oehlschlager, Can. J. Chem. 51, 2406 (1973). 

Tri-p-tolylphosphine refluxed several hrs. with 10%-excess monodiloromethyl ether in benzene, and the resulting dhloride treated with Na-fluoroborate soln. in water (methoxymethyl)tris-(p-tolyl)phosphonium fluoroborate (Y 91%) added to nitryl fluoroborate and sulfolane, heated 6 hrs. at 110, pyridine hydrochloride added, and stirred 2 hrs. at 115° tris-(3-nitro-4-methylphenyl)phosphine (Y 51%). - Phosphonium salt formation protects the phosphorus from oxidation. F. e. s. G. P. Schiemenz and K. Rohlk, B. 104, 1219 (1971). 

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