in tetrahydrofuran 4h, 40°C;;

zinc/copper couple in tetrahydrofuran; toluene Ar atmosphere, addn. of soln. of MeI to Cu/Zn, filtration, cooling (-30°C), addn. of Me2SnCl2 in THF/toluene (1:1) (dropwise, stirring, 2 h), stirring, (50°C, 12 h), solvent removed; dissolving (toluene), washing (HCl), drying (over Na2SO4), filtration, distn. (0.1 Torr); elem. anal.;

potassium hydroxide in ethanol (under Ar); mixt. of Sn-compounds diluted in EtOH added dropwise to soln. of KOH in EtOH at room temp. for 2 h; poured into H2O, extd. with CH2Cl2, extract washed with H2O, dried, concd., chromd. on Al2O3 with 1:6 CH2Cl2:C6H14;

potassium hydroxide in ethanol mixt. of Sn- and Si-compounds diluted in EtOH soln. of KOH at room temp.for 2 h;

in ethanol Sn-compound reacted with Na2Se2 in EtOH at 0°C;

sodium tetrahydroborate in tetrahydrofuran; ethanol (under Ar); mixt. of Sn-compounds added dropwise to suspn. of NaBH4 in EtOH-THF with stirring at room temp., stirred for 10 min; concd. in vacuo, poured into H2O, extd. with CH2Cl2, extract washed withH2O, dried, concd. in vacuo, chromd. on silica gel with 1:7 CH2Cl2:C6H1 4;

in ethanol Sn-compound reacted with Na2Te2 in EtOH;