Halogen Exchange Reaction

Halogen Exchange Reactions. Halogen exchange can be accomplished with reactive alkyl halides, such as Benzyl Chloride or Benzyl Bromide, and even with certain alkyl fluorides, by using TMS-I in the presence of ( -Bu)4NCl as catalyst (eq 17). 

Halogen Exchange Reactions. Halogen exchange can be accomplished with reactive alkyl halides, such as Benzyl Chloride... 

The melting, boiling, and sublimation points of many of the phosphoms hahdes are well defined and therefore serve for identification. Distillation is the easiest method of purification. Phosphoms-31 nmr can be used to analy2e mixtures of hahdes that undergo halogen-exchange reactions. 

Fluorinated and iodinated derivatives are usually prepared by halogen exchange reactions, although the Baltz-Schiemann reaction has been applied to the synthesis of 2-fluoroquin-oxaline (66JHC435>. 

SELECTIVE HALOGEN-LITHIUM EXCHANGE REACTIONS OF 2- 2 -HAL0PHENYL)ETHYL HALIDES ... 

The halogen-metal exchange reaction was pioneered by Gilman and co-... 

Polymer-supported tetraphenylphosphonium bromide is a recyclable catalyst for halogen-exchange reactions. The reaction of 1 equivalent of chloro-2,4-dinitrobenzene with 1 5 equivalents of spray-dned potassium fluoride and 0.1 equivalent of this catalyst in acetonitnle at 80 C for 12 h gives 2,4-dinitro-fluorobenzene m 98% yield An 11% yield is obtained without the catalyst [3 /]. 

The metal-halogen exchange reaction is useful in the synthesis of numerous perfluoroalkylmagnesium halides, some of which are shown in Table 2... 

Although the metal-halogen exchange reaction is the preferred method of synthesis, the conventional Grignard synthesis through the reaction of a per-fluoroorgano halide and magnesium occasionally is still used [49, 50]... 

Novel polyfluoroethyl Gngnard reagents containmg fluonne, chlorine, and bromine are prepared through the metal-halogen exchange reaction [46] (equation 20)... 

Radioactive isotopes of the halogens have found use in the study of isotope-exchange reactions and the mechanisms of various other reactions.The properties of some of the most used isotopes are in Table 17.5. Many of these isotopes are available commercially. A fuller treatment with detailed references... 

Among the nucleophilic processes available for introduction of bromine to quinolines are reactions of the diazonium salts (87JHC181) and syntheses based on hydroxyquinolines or quinolones (91M935) (Scheme 36). The former processes are especially useful for making 5-, 6-, 7-, and 8-bromo derivatives. Halogen-halogen exchange reactions have also been reported, but they are not common. When perfluoroquinoline was heated... 

An example of intramolecular conjugate addition of aryllithium generated by halogen metal exchange reaction of 92 is illustrated in equation 7966. 

An interesting, halogen-exchange reaction takes place when [Ni(Et2dtc)2] is refluxed in 1,2-dichloroethane with an excess of a,a -di-bromo-o-xylene and a-bromo-a -chloro-o-xylene. The products, a,a -... 

---