More Polar Organometallics

I. by Reaction with More Polar Organometallics (Metal-Metal Exchange, Excluding Amino-, Oxo- and Thioboron Halides). 

S.3.2.4. from Boron Alkoxides with More-Polar Organometallics... 

The first metal-ate complex, sodium triethylzincate, " was obtained by John Wanklyn who treated diethylzinc with elemental sodium in an attempt to produce ethylsodium. A systematic and reliable approach to ate complexes is the addition of a more polar organometallic reagent (eg., an organolithium) to a less polar organic derivative of an alkali-earth metal, transition element, or metalloid. In this way, a wealth of ate complexes of berrylium, magnesium, zinc, copper, boron, aluminum, silicon, tin, and mercury as well as of nonmetals like phosphorus, sulfur, selenium, tellurium, and even iodine " have been obtained. 

When the products are partially or totally miscible in the ionic liquid, the separation of the products can be more complicated. It is however possible to reduce the solubility of typical organic products in the ionic liquid by introducing a more polar solvent that can be separated by distillation afterward at a lower temperature (27). Because of the low vapor pressure of the ionic liquid, direct distillation can be applied without azeotrope formation (28). However, such operation is often limited to highly volatile or thermally labile products because of the general thermal instability of organometallic catalysts. 

Reactions of polar organometallic and Grignard reagents with a-haloethers generally proceed much more easily than the familiar SN2 displacements with alkyl halides. This may be explained by the large extent of Sjql character due to the ionization ... 

The more polar the carbon-metal bond, the more reactive the organometallic reagent. 

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