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 and CH3OH. The mixt. was stirred(10 min) and then at -63°C (12 h). Satd. aq. NH4Cl and ether were added; allowed to warm to room temp.; Aq. phase was extd. (ether). The org. exts. were washed (satd. aq. NH4Cl) and dried (MgSO4). Removal of the solvent; column chromy. (silica gel) followed by distn. (12 Torr). (E)-1-trimethylstannyl-1-alkene not isolated, detected by gas-liq. chromy..;

methanol in tetrahydrofuran molar ratio Sn:alkyne:MeOH=1:2:60; chromy. (SiO2, light petroleum);

in tetrahydrofuran addn. of the chloro compound to a soln. of the Cu compound in dry THF at -78°C, stirring for 6 h, addn. of CH3COOH, MeOH, aq. NH4Cl/NH4OH (pH 8) and (C2H5)2O; performed under Ar;; extn. with diethyl ether after warming to room temp.; washing with aq. NH4Cl/NH4OH, drying over MgSO4, concn.; column chromy. (silica gel, petroleum ether) and distillation (80-85°C, 25 Torr);;

methyllithium in tetrahydrofuran T=-78°C; 0.25 h;

1: MeLi / tetrahydrofuran / 0.25 h / -78 °C 2: 1)n-Bu3P / 1)CuBr*Me2S / 1)THF, -78 deg C, 20 min 2)-78 deg C, 1h, then -40 deg C, 2 h View Scheme

1: MeLi / tetrahydrofuran / 0.25 h / -78 °C 2: 1)n-Bu3P / 1) CuBr*Me2S, 2.) BF3*Et2O / 1)THF, -78 deg C, 20 min 2)-78 deg C, 1 h, then -40 deg C, 2 h View Scheme

Yield given. Multistep reaction;