Oxonium, trimethyl-, tetrafluoroborate

Oxone Peroxymonosulfuric acid, monopotassium salt, mixt. with dipotassium sulfate and potassium hydrogen sulfate (37222-66-5), 69, 160, 229 Oxonium, trimethyl-, tetrafluoroborate (1-), 65,140 (1-OXO-2-PROPENYL)TRIMETHYLSILANE, 66,14-16,18 3-(1-Oxopropyl)-4-(S)-phenylmethyl-2-oxazolidinone 2-Oxazolidinone, 3-(1-oxopropyl)-4-(phenylmethyl)-, (S)- (101711-78-8), 68, 83 Ozone (10028-15-6), 65, 183... 

Triethyloxonium fluobotate [Oxonium, triethyl-, tetrafluoroborate(l-)), 59 TVTrifluoroacetylation, 122 Trimethyloxonium fluoborate [Oxonium, trimethyl-, tetrafluoroborate(l-),... 

That some modification to the position so far described might be necessary was indicated by some experiments of Nesmeyanov and his co-workers. Amongst other compounds they nitrated phenyl trimethyl ammonium and triphenyloxonium tetrafluoroborates with mixed acid the former gave 96 % of m- and 4 % of -nitro compound (88 % total yield), whilst the latter gave 80% of the tri-(p-nitrophenyl)oxonium salt. Ridd and his co-workers have made a quantitative study of the phenyl trimethyl ammonium ion. Their results, and those of other recent workers on the nitration of several cations, are collected in table 9.3. 

The benzoxazepinone 2 is converted into 5-methoxy-l,4-benzoxazepine (8a) by trimethyl-oxonium tetrafluoroborate.32 An analogous reaction of 3-phenylbenzoxazepinonc 3 with tri-cthyloxonium tetrafluoroborate gives the 5-cthoxy derivative 8b. The thione 6 undergoes methylation at sulfur to yield the (methylsulfanyl)benzoxazepine 9.32... 

The 1,5-benzothiazepin-4(5//)-ones 2 undergo 0-methylation on treatment with trimethyl-oxonium tetrafluoroborate to give 4-methoxy-l, 5-benzothiazepines 7 a56 and 7b.51... 

Boron trifluoride, with dimethyl ether and epichloro-hydrin to give trimethyl-oxonium tetrafluoroborate,... 

Selenanes with exocyclic methylene substituents can be efficiently methylated at the selenium atom using trimethyl-oxonium tetrafluoroborate (Equation 48) <1994JOC1011>. 

The third and final general protocol for the hydrolysis of 5 5-acetals exploits the very easy reaction of the sulfur atom of an S-acetal with alkylating agents such as iodomethane, trimethyl- or triethyl-oxonium tetrafluoroborate, and methyl triHuoromethanesuLfonate to form the corresponding trialkylsulfonium salts. Ley s approach to the potent insect antifeedant Azadirachtin [Scheme 2 81]135,171,172 benefited from an easy S-alkylation-hydrolysis sequence. In a synthesis of Epiantillatoxin, a more difficult liberation of an aldehyde from its dithiane derivative was accomplished without rearrangement of a p,y-alkene into conjugation [Scheme 2,82].173... 

The sulfur atom of naphthothiete 205 may be methylated with trimethyl-oxonium tetrafluoroborate to give the stable salt. 3-Phenylthiete 213 may be alkylated with trimethyl- or triethyloxonium tetrafluoroborate or the trifluoro-methanesulfonate esters The salts are unstable. Alkylation of 218b with methyl iodide gives a ring-opened product, the reaction being facilitated by electron donation from the iron atom. ... 

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