Organomercury compounds with metals

A number of metals salts can be used as the source of electrophiles in reactions with alkenes. One of the most interesting of these involves the attack of mercury(II) acetate in acetic acid. Reductive cleavage of the organomercury compound with sodium borohydride leads to the overall hydration of the alkene in a Markownikoff sense. There are a number of preparative advantages, such as a reduced tendency to rearrange, associated with this and similar relatively mild procedures when compared to the direct protonation of a double bond (Scheme 3.14)... 

Organomercury compounds are widely used for syntheses of organometallic compounds by the transmetalation or metathesis reaction similar to organozinc compounds. For example, organozinc compounds and organomagnesium compounds (1866) are prepared by the transmetalation of organomercury compounds with a metal [30,31]. 

Scheme 10 Transmetalation of an organomercury compound with alkaline-earth metals yielding the corresponding pentafluorophenyl complexes...

In mercury speciation studies, pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), and supercritical fluid extraction (SEE) are employed [33]. In particular, methyl-mercury is extracted by the Westoo method [33,34], which consists in a leaching process with hydrochloric acid, the extraction of the metal chloride into benzene or toluene, the addition of ammonium hydroxide that converts the metal species to hydroxide and the saturation with sodium sulfate. Most of the HPLC methods reported in literature for the determination of organomercury compounds (mainly monomethyhnercury, monoethyhnercury, and monophenylmercury) are based on reversed... 

Organomercury compounds such as ICFbHgl and Hg(CH2Br)2 may be prepared by the reaction of metallic mercury with diiodomethane or by reaction of mercury(II) salts with diazoalkanes. These mercury derivatives are related to the intermediate that has been proposed in the Simmons-Smith reaction, and likewise, they have been found to convert alkenes into cyclopropanes.92... 

Over 35 years ago, Richard F. Heck found that olefins can insert into the metal-carbon bond of arylpalladium species generated from organomercury compounds [1], The carbopalladation of olefins, stoichiometric at first, was made catalytic by Tsutomu Mizoroki, who coupled aryl iodides with ethylene under high pressure, in the presence of palladium chloride and sodium carbonate to neutralize the hydroiodic acid formed (Scheme 1) [2], Shortly thereafter, Heck disclosed a more general and practical procedure for this transformation, using palladium acetate as the catalyst and tri-w-butyl amine as the base [3], After investigations on stoichiometric reactions by Fitton et al. [4], it was also Heck who introduced palladium phosphine complexes as catalysts, enabling the decisive extension of the ole-fination reaction to inexpensive aryl bromides [5],... 

The R2Zn compounds may be obtained in several ways (1) by reactions of ZnCl2 with RLi, R2Mg, or R3AI compounds (2) for the aryls especially, the reaction of the metal with an organomercury compound ... 

By reacting directly with the alkali metal, organomercury compounds are commonly used to synthesize organoalkali metal compounds of the heavier alkali metals. This route has been used to make various alkyl compounds, such as butyl and trimethylsilylmethyl derivatives (equation 10). 

Alkylalkali metal compounds are also commonly formed from reactions with organomercury compounds. Solvent-free LiC(SiMe3)3 has been prepared by the reaction of an organomercuryhalide with butyl lithium in hexanes (equation 19). ... 

Biphosphines may be formed by several methods involving the treatment of phosphinous halides with either electropositive metals or organomercury compounds. An additional intriguing approach involves the reaction of metal organophosphides (see Section 3.2) with 1,2-dibromoethane to form the phosphorus-phosphorus bond and extrude ethylene (equation 17). 

Organometallic compounds of less active metals and metalloids (e.g., silicon," antimony, and bismuth, are quite inert to water. Organomercury compounds (RHgX or R2Hg) can be reduced to RH by H2, NaBITj, or other reducing agents." The reduction with NaBH4 takes place by a free-radical mechanism." Alkyl-Si... 

Ever since they were first reported, organometallic compounds have been known to have biological effects. The experiences of Frankland and Bunsen have already been mentioned. Two workers were poisoned, both fatally, by dimethylmercury in 1866 (H5). Industrial development of metal carbonyls and tetraethyllead caused a number of deaths 188, 265). In general, organoarsenic compounds have been most investigated for their toxic effects, with organomercury compounds a close second. Table V outlines the chronology of these developments, and Fig. 2 shows some representative compounds studied. 

Wacker-type oxidative reactions of olefins with nucleophiles, reactions of zr-allyl-palladium complexes with nucleophiles, reactions based on chelation, and trans-metallation of organomercury compounds. 

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