Phenyltrimethylammonium bromide perbromide

Bromination of 5j5-3-ketones yields the equatorial 4 -bromo compounds (22) as the thermodynamic or kinetic products,although the presence of a considerable amount of 2-bromo isomer has been reported in bromination with phenyltrimethylammonium bromide-perbromide. This is in keeping with other evidence that enolization of 5j5-3-ketones is not specifically directed to C-4. Cleaner results would probably be obtained via thermodynamic enol acelylation. ... 

Phenyltrimethylammonium bromide perbromide (PhMe3N Br3) was introduced as a reagent for the bromination of cyclic ketals81 (see section IV) but it has also been utilized for the selective bromination of ketones containing double bonds.82 The same claim has been made for cupric bromide as a brominating agent 83 yields are not good, however, and in methanol, the solvent usually employed, the formation of methoxy-substituted products is a common side reaction (cf. ref. 84, 85). 

Dich lorotris(triphenylphosphine)-ruthenium. Dimethyl(2,4,6-tri-/-butylphenoxy)chlorosilane. Lithiocyclopropyl phenyl sulfide. Nafion-H. PaLIadium(II) acetate-1,2-Bis(diphenylphosphino)ethane. Palladium(II) chloride. Phenyltrimethylammonium perbromide. Potassium hydride. Potassium permanganate. 2-Pyridylsclcnenyl bromide. 

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