Hypohalites, acyl

The latter is an exttemely reactive species. Trifluoroacetate is a good leaving group and facilitates cleavage of the O—Br bond. The acyl hypohalites are also the active halogenating species in solutions of the hypohalous acids in carboxylic acids, where they exist in equilibrium. 

The first step is not a free-radical process, and its actual mechanism is not known. Compound 30 is an acyl hypohalite and is presumed to be an intermediate, though it has never been isolated from the reaction mixture. Among the evidence for the mechanism is that optical activity at R is lost (except when a neighboring bromine atom is present, see p. 899) if R is neopentyl, there is no rearrangement, which would certainly happen with a carbocation and the side products, notably RR, are consistent with a free-radical mechanism. There is evidence that the Simonini... 

Halogenations are strongly catalyzed by mercuric acetate or trifluoroacetate. These conditions generate acyl hypohalites, which are the active halogenating agents. The trifluoroacetyl hypohalites are very reactive reagents. Even nitrobenzene, for example, is readily brominated by trifluoroacetyl hypobromite.19... 

Unstable above 22°C and explosive in gas phase at pressures above 27-63 mbar. See entry ACYL HYPOHALITES (reference 1)... 

Propionyl hypobromite [82198-80-9] EtCO.OBr Skell, P. S. et al., J. Amer. Chem. Soc., 1983, 105, 4000 As an isolated solid it is unpredictably explosive. See Other ACYL HYPOHALITES C3H5Br02... 

See other acyl hypohalites, oxidants See related acyl halides... 

Alkyl and acyl hypohalites, when adding to carbon-carbon double bond, afford halohydrin ethers and esters, respectively.151 Regioselective and syn stereoselective addition of CF3OF, CF3CF2OF, and CF3COOF to stilbenes was reported.152-154 The stereochemistry was explained to originate from the formation and immediate... 

A variation of the general procedure discussed in this section consists of using acyl hypohalite addition to double bonds, according to Eq. (129). 

The acyl hypohalit reaction with iodine ob a halogen component is the well-known Prevost reaction,18i0 whioh has found some application during recent years in the field of natural prodwtB.. u. . w. In thiB ease the acyl hypoholite is acetyl hypoiodite, generated by reaction of iodine with silver nitrate in glacial acetic arid (Eq. 130). 

A minor explosion in the use of gaseous acetyl hypofluorite was caused by inadvertent contact of the gas inlet tube with a cooling bath, which condensed liquid hypofluorite which subsequently exploded on contact with organic material or air [ 1 ]. More detail on the isolation of this compound of limited stability, particularly in the liquid phase, is given [2]. See other ACYL HYPOHALITES, OXIDANTS... 

See Fluorine Caesium heptafluoropropoxide See other ACYL HYPOHALITES... 

Pentafluorotellurium hypofluorite, 4363 Perfluoro-ferf-butyl peroxyhypofluorite, 1369 Tetrafluoroiodosyl hypofluorite, 4350 Trifluoromethyl hypofluorite, 0352 See also ACYL HYPOHALITES, BIS(ELUOROOXY)PERHALOALKANES... 

Tetrafluoroammonium hexafluoromanganate, 4378 Tetrafluoroammonium hexafluoronickelate, 4379 Tetrafluoroammonium hexafluoroxenate, 4380 Tetranitromethane, 0543 Titanium tetraperchlorate, 4164 1,1,1 -Triacetoxy-1,2-benziodoxol-3-one, 3604 Trifluoromethyl hypofluorite, 0352 Trimethylsilyl chlorochromate, 1297 Trioxygen difluoride , 4317 Uranium hexafluoride, 4369 Vanadium trinitrate oxide, 4758 Vanadium(V) oxide, 4860 Vanadyl perchlorate, 4146 Xenon hexafluoride, 4371 Xenon tetrafluoride, 4347 Xenon tetrafluoride oxide, 4340 Xenon tetraoxide, 4857 Xenon trioxide, 4851 Xenon(II) pentafluoroorthoselenate, 4376 Xenon(II) pentafluoroorthotellurate, 4377 Zinc permanganate, 4705 ACETYLENIC PEROXIDES ACYL HYPOHALITES ALKYL HYDROPEROXIDES ALKYL TRIALKYLLEAD PEROXIDES AMINIUM IODATES AND PERIODATES AMMINECHROMIUM PEROXOCOMPLEXES BIS (FLUOROOXY)PERHALOALKANES BLEACHING POWDER CHLORITE SALTS... 

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