Organosodium chemistry

Transmetallation routes In the original work the alkylsodium compound was accessed from the dialkylmercury compound by transmetallation. For example, diethylmercury in the Schorigin reaction or Shorygin reaction: :(C2H5)2Hg + 2 Na → 2 C2H5Na + Hg The high solubility of lithium alkoxides in hexane is the basis of a useful synthetic route: :2 Na+ 2 C5H6 → 2 Na+ C5H5− + H2 Sodium acetylides form similarly. Often strong sodium bases are employed in place of the metal. Sodium methylsulfinylmethylide is prepared by treating DMSO with sodium hydride: :CH3SOCH3 + NaH → CH3SOCHNa+ + H2 Metal-halogen exchange Trityl sodium can be prepared by sodium-halogen exchange: The related anthracene as well as lithium derivatives are well known. ==Structures==

Simple organosodium compounds such as the alkyl and aryl derivatives are generally insoluble polymers. Because of its large radius, Na prefers a higher coordination number than does lithium in organolithium compounds. Methyl sodium adopts a polymeric structure consisting of interconnected [NaCH3]4 clusters. -PMDTA adduct, hydrogen atoms omitted for clarity. ==Reactions==

Organosodium compounds are traditionally used as strong bases, organosodium compounds react with carbon dioxide to give carboxylates: :C2H5Na + CO2 → C2H5CO2Na Grignard reagents undergo a similar reaction. Some organosodium compounds degrade by beta-elimination: :NaC2H5 → NaH + C2H4 ==Industrial applications==

Although organosodium chemistry has been described to be of "little industrial importance", it once was central to the production of tetraethyllead. A similar Wurtz coupling-like reaction is the basis of the industrial route to triphenylphosphine: :3 PhCl + PCl3 + 6 Na → PPh3 + 6 NaCl The polymerization of butadiene and styrene is catalyzed by sodium metal. ==Organic derivatives of the heavier alkali metals==

Organopotassium, organorubidium, and organocaesium compounds are less commonly encountered than organosodium compounds and are of limited utility. These compounds can be prepared by treatment of alkyl lithium compounds with the potassium, rubidium, and caesium alkoxides. Alternatively they arise from the organomercury compound, although this method is dated. The solid methyl derivatives adopt polymeric structures. Reminiscent of the nickel arsenide structure, MCH3 (M = K, Rb, Cs) has six alkali metal centers bound to each methyl group. The methyl groups are pyramidal, as expected. A notable reagent that is based on a heavier alkali metal alkyl is Schlosser's base, a mixture of n-butyllithium and potassium tert-butoxide. This reagent reacts with toluene to form the red-orange compound benzyl potassium (KCH2C6H5). Evidence for the formation of heavy alkali metal-organic intermediates is provided by the equilibration of cis-but-2-ene and trans-but-2-ene catalysed by alkali metals. The isomerization is fast with lithium and sodium, but slow with the higher alkali metals. The higher alkali metals also favor the sterically congested conformation. Several crystal structures of organopotassium compounds have been reported, establishing that they, like the sodium compounds, are polymeric. ==See also==