ammonium chloride in tetrahydrofuran; water To a stirred soln. of Me3SnCu*Me2S in THF (Ar, -78°C) was added a THF soln. of 3-tert-butyldimethylsiloxypropyne. The mixt. was stirred (6h). Satd. aq. NH4Cl and ether were added; allowed to warm to room temp.; The org. phase was washed (satd. aq. NH4Cl) and dried (MgSO4). Removal of the solvent; flash chromy. (silica gel) provided 3-tert-butyldimethylsiloxy-2-trimethylstannylpropene and (E)-3-tert-butyldimethylsiloxy-1-trimethylstannylpropene.;

in tetrahydrofuran molar ratio Sn:alkyne=1:2, -78°C; chromy. (SiO2, light petroleum);