SOME APPLICATIONS OF THE METHYLENE DI-GRIGNARD REAGENT FOR THE SYNTHESIS OF MAIN GROUP IV ORGANOMETALLIC COMPOUNDS

Article abstract of DOI:10.1016/0022-328X(85)80101-7

The di-Grignard reagent methylenedimagnesium dibromide, CH2(MgBr)2 (1), which can be prepared from dibromomethane and magnesium amalgam in diethyl ether/benzene 1/1, has been obtained in a pure form.Treatment of 1 with tetrahydrofuran gave insoluble 5'', a reagent with the approximate composition CH2Mg*CH2(MgBr)2.Both reagents were used for the synthesis of the dimetallomethanes (Me3M)2CH2 (M = Si, Ge, Sn) and (CH2(HgBr)2.Reaction of 1 or 5'' with dichlorodimethylgermane or dichlorodimethylstannene gave the polygermacycloalkenes ((Me2GeCH2)_n; n = 2,3,4) or polystannacycloalkenes ((Me2SnCH2)_n; n = 3,4), respectively, in useful yields (10 to 35percent).In the germanium series, there is a pronounced tendency to form the smaller ring system; in particular, the reaction of 5'' with Me2GeCl2 gave 30-35percent of 1,1,3,3-tetramethyl-1,3-digermacyclobutane.In contrast, the corresponding distannacyclobutane was not observed, but the eight-membered species (Me2MCH2)4 was formed more readily for M = Sn (9percent yield) than for M = Ge (2percent yield).