ammonium chloride in tetrahydrofuran; methanol; water To a stirred soln. of Me3SnCu*Me2S in THF (Ar, -78°C) was added sequentially a THF soln. of the 1-alkyne. The mixt. was stirred (6h). CH3OH, 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-tetrahydropyranyloxy-2-trimethylstannylpropene and (E)-3-tetrahydropyranyloxy-1-trimethylstannylpropene.;

aluminium trichloride in not given Ar-atmosphere; treatment with water; isomer mixt. not sepd., detd. by NMR spectroscopy;elem. anal.; total yield 71percent;

azobis(isobutyrinitrile) heating at 60°C (Ar) for 1-2 h; distn. in vac.; NMR;