THE REACTION OF (ME3SI)3CBR WITH MG IN TETRAHYDROFURAN (THF) OR DIETHYL-ETHER - CRYSTAL-STRUCTURE OF (ME3SI)3CMG(MU-BR)3MG(THF)3

The only product isolated from the reaction of (Me3Si)3CBr with Mg in THF was, as shown by an X-ray diffraction study, (Me3Si)3CMg(mu-Br)3Mg (THF)3, which contains one four-coordinate and one six-coordinate Mg a tom. A similar product, (Me3Si)3CMg(mu-Br)3Mg(Et2O)x, appears to be fo rmed in the reaction in ether. It is suggested that the high Br/(Me3Si )3C ratio in the products may be associated with formation of (Me3Si)3 C radicals (which go on to give (Me3Si)3CH) during the reaction with M g.