Metal organohalides

The transition metal catalyzed cross coupling of an organohalide with a boronic acid derivative, the Suzuki-Miyaura coupling, has become one of the most popular ways of preparing biaryls.3 The reaction is very robust and can easily be scaled to provide multigrams of material.4... 

Grignard reagents are usually prepared by the reaction of an organohalide and magnesium metal (turnings) in an ether solvent. 

Addition of organomagnesium compounds (Grignard reagents), generated from organohalides and magnesium metal, to electrophiles. 

The reaction of heterocyclic lithium derivatives with organic halides to form a C-C bond has been discussed in Section 3.3.3.8.2. This cannot, however, be extended to aryl, alkenyl or heteroaryl halides in which the halogen is attached to an sp2 carbon. Such cross-coupling can be successfully achieved by nickel or palladium-catalyzed reaction of the unsaturated organohalide with a suitable heterocyclic metal derivative. The metal is usually zinc, magnesium, boron or tin occasionally lithium, mercury, copper, and silicon derivatives of thiophene have also found application in such reactions. In addition to this type, the Pd-catalyzed reaction of halogenated heterocycles with suitable alkenes and alkynes, usually referred to as the Heck reaction, is also discussed in this section. 

Boronina T, Klabunde KJ, Sergeev G. Destruction of organohalides in water using metal particles carbon tetrachloride/water reactions with magnesium, tin, and zinc. Environ Sci Technol 1995 29 1511-1517. 

These nucleophilic reagents react with most common electrophiles such as organohalides, tosylates, aldehydes, ketones, epoxides, and activated alkenes. It should be noted that many workers have found much higher yields if the phosphides are protected as phosphine oxide or borane anions (see Section 3). Phosphide reagents also react with activated arenes to give mixed aryl phosphines (Protocol 2). Metal phosphides therefore provide an alternative, complementary tertiary phosphine synthesis to the electrophilic routes outlined in Section 2.1. 

The direct reaction of an organic halide with an alkali metal is one of the most important methods for synthesizing organohthium compounds. The reaction of two equivalents of the alkali metal with one equivalent of the organohalide produces the organoalkah metal compound and metal halide... 

Antimony forms nnmerons stable pentavalent organo-metallic componnds among these are penta alkyls and aryls, mixed organohalides, and varions chalcogen and nitrogen derivatives. 

Although simple analytical tests often provide the needed information regarding a water sample, such as the formation and presence of chloroform and other organohalides in drinking water, require some very specialized methods of analysis. The separation of trace metals into total and uncomplexed species also requires special sample handling and analysis (12). 

I. from Silyl-Alkali-Metal Reagents with Group-IIB Halides and Organohalides. 

Organohalides, RX, react with magnesium metal in ether or tetrahydro-furan (THF) solvent to yield organomagnesium halides, RMgX. The products, called Grignard reagents after their discoverer, Victor Grignard, are... 

In the first work on the PTC carbonylation of organohalides, Pd(PPh3)4 was used as a metal catalyst [110]. There are a number of other examples of the use of Pd° complexes in two-phase carbonylations. The selective formation of one of four possible products, including esters, depends mainly on the composition of the metal complex (e. g., Pd(PPh3)4 vs. Pd(dba)2) [129]. Radical intermediates may be involved in the formation of several of the products. Esters (e. g., benzyl phenylacetate from benzyl bromide) are the major products of the carbonylation of benzyl bromides using a zwitterionic rhodium catalyst [130]. 

---