Cadmium organomercurials

Main group tetrafluoroterephthalates lose both carboxyl groups. Mercury and cadmium tetrafluoroterephthalates when heated in vacuo gave polymeric tetrafluorophenylenemercury and -cadmium compounds [Eq. (92), M = Hg or Cd] (103). The same organomercurial and mercury... 

By contrast to the zinc and cadmium xanthates, for which organoelement xanthate structures are not known, there exists a rich structural chemistry of organomercury xanthates. 

The organomercurials R2Hg could also be used to obtain the organo derivatir es of zinc 51), cadmium (52), and aluminum (55) via the exchange process... 

Whereas organomercury compounds do not add to aldehydes and ketones, cadmium organometallics show a useful reactivity. As in the case of organozinc derivatives, allylic cadmium compounds... 

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 ... 

Linear organomercurials provide a convenient basis for the investigation of the effect of susbstitution in the organic moiety on the metal chemical shift. Increase in the shielding of 150 ppm are observed for each substitution of Me for a H in Hg-CH3 derivatives, while smaller decreases in shielding ( 30 ppm) occur on substitution of )S-Hs. Cadmium alkyls show a similar behavior, but for silyl mercury compormds, replacements at both a and position results in deshielding. 

Organomercury and organocadmium compounds are much less reactive than the corresponding lithium or magnesium derivatives, and are therefore useful for certain reactions where selectivity is important. One useful synthetic application of this strategy is the preparation of ketones from acid chlorides and cadmium reagents. Cadmium reagents are useful because they are too unreactive to add to the product ketone, and the reaction therefore stops at the ketone. 

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