hydrogen bromide in dichloromethane to soln. of Sn compd. added slowly (2 h) soln. of 2.1 equiv of HBr at -78°C, slowly warmed to 25°C, reacted for 8-10 h; evapd. (vac.), chromd. (MeCN or MeCN/THF);

iodine; magnesium in tetrahydrofuran (N2); to suspn. of Mg and I2 at 25°C added over 1 h soln. of Br(CH2)8Br, 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 or MeCN/THF); elem. anal.;

in tetrahydrofuran dilute (0.03 M) solns. of reagents were added simultaneously to THF over 2 h at 25°C; purified by reverse phase chromy. and recrystn.;

1: tetrahydrofuran 2: HCl / dichloromethane 3: tetrahydrofuran View Scheme

1: tetrahydrofuran 2: HCl / dichloromethane View Scheme