iodine; magnesium in tetrahydrofuran (N2); to suspn. of Mg and I2 at 25°C added over 1 h soln. of Br(CH2)4Br, stirred for 4 h, sepd. from excess of Mg, diluted with THF, added over 2.5 h to Sn-compd. soln. at 0°C, allowed to warm to 25°C, stirred for 10 h; satd. aq. NH4Cl added at 0°C, aq. layer extd. (ether), combined ethereal solns. washed (satd. aq. NaCl), dried (MgSO4), filtered, concd., chromd. (MeCN/THF), recrystd. (hexane); elem. anal.;

in tetrahydrofuran (N2); soln. of dilithium compd. added over 1 h to dibromo-compd. soln. at 0°C, allowed to warm to room temp., stirred for 14 h; satd. aq. NH4Cl added at 0°C, aq. layer extd. (ether), combined ethereal solns. washed (satd. aq. NaCl), dried (MgSO4), filtered, concd., chromd., recrystd. (hexane); elem. anal.;

in tetrahydrofuran (Ar or N2); (BrMgC2H4)2 in THF added over 2 h to 1 molar equiv of Sn compd. in THF at 0°C, reacted for 12 h at room temp.; treated with satd. aq. NH4Cl, aq. phase extd. (ether), combined org. phases washed with satd. aq. NaCl, dried (MgSO4), evapd. (vac.), purified by reverse-phase chromy. (THF/MeCN), recrystd.;