in tetrahydrofuran argon atmosphere, room temperature, passing acetylene into THF, addn. of a soln. of Mg-compound followed by addn. of a soln. of Sn-compound, heating for 2 h, stirring for 1.5 h at 55-60°C; addn. of pentane, decanting liquid layer, removing solvent, distn. (vac.), elem. anal.;

in diethyl ether a soln. of Me(t-Bu)2SnBr in ether is added to a soln. of tert-butylchloromagnesium in ether and the reaction mixt. is boiled for 15 h with stirring under Ar;; distn.; elem. anal.;

in tetrahydrofuran heated at 90-100°C for 3 h; added pentane, ppt. separated, distillated from solvent; elem. anal.;

in tetrahydrofuran heated at 90-100°C for 3 h; added pentane, ppt. separated, distillated from solvent; elem. anal.;

in tetrahydrofuran heated at 90-100°C for 3 h; added pentane, ppt. separated, distillated from solvent; elem. anal.;