in tetrahydrofuran a cold (-78°C) soln. of trimethylstannyl-lithium in dry THF was allowed to react with methyl (E)-2-butenoate for 5 min; the mixt. was stirred under dry Ar atm. at -78°C for 15 min;; column chromy. (in mixt. of methanol and diethyl ether) followed by the elution with diethyl ether; removal of the solvent by distn.;

in tetrahydrofuran a cold (-20°C) soln. of ((CH3)3SnCuSC6H5)Li in dry THF was allowed to react with methyl(E)-2-butenoate; the mixt. was stirred under dry Ar atm. at -20°C for 15 min and at room temp. for 1 h;; the slurry (MeOH/Et2O) was filtered through a short column of Florisil, then the column was eluted with diethyl ether; removal of the solvent by distn. (air-bath temp.41-50°C/0.2 Torr); elem anal.;

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