Organometallic reactions organomercury reagents

Metathesis reactions continue to be extensively employed in the synthesis of organomercury compounds. While most reactions involve the use of organolithium or Grignard reagents, other organometallic compounds are sometimes used as starting materials. 

The oxidative-reductive transmetallation can be carried out with organometallic reagents that have a reduction potential more positive than magnesium ( — 2.375 V). Since these reactions are typically carried out with organomercury derivatives, there is a major environmental issue with formation of Hg , resulting in this method rarely being used, even in the laboratory. 

The preparation of organolithiums by reaction (a) is of limited synthetic utility because the organomercurials are prepared from other organometallic reagents, most often organomagnesium halides or organolithiums. In addition, reaction (a) is slow, although ultrasonic irradiation increases the rate. 

In this section, we will discuss organometallics in which the metal is cadmium, mercury, or zinc. Grignard reagents and organolithium compounds can be converted to heavy-metal derivatives by reaction with salts of these metals. The reaction is driven forward by the tendency for formation of the ionic salt of the more electropositive metal. This reaction is well documented for organocadmium compounds and organomercurials ... 

As shown in eqs. (5.3)-(5.7), organozinc compounds are easily prepared by the reactions of zinc compounds or zinc metal with organometallic compounds such as Grignard reagents, organoaluminum compounds, organomercury compounds and organolithium compounds [12,13,18]. 

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