Bromomagnesium Tellurolates

Tellurium inserts into the magnesium-carbon bond in aryl magnesium bromides. The resulting bromomagnesium arenetellurolates were not isolated but used in situ. Diethyl ether or tetrahydrofuran served as the reaction medium. 

The scope of the reaction of tellurium with Grignard reagents has not yet been delineated. Several aromatic and aliphatic Grignard reagents were reported to be unreactive toward tellurium. Bromomagnesium ethenetellurolates and vinylmethanetellurolate are the only aliphatic magnesium tellurolates are prepared. 

Bromomagnesium Ethenetellurolate Elemental tellurium (0.6 g, 5 mmol) is added to a solution of vinylmagnesium bromide (5.5 mmol) in 10 ml of tetrahydrofuran kept under an atmosphere of nitrogen. The mixture is refluxed for 20 min and then cooled to room temperature. 

The extreme sensitivity of tellurolates to moisture and oxygen makes the isolation of these tellurium compounds difficult. Therefore, tellurolates are almost always prepared under an inert atmosphere and used in situ. 

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