n-butyllithium in diethyl ether; hexane Addn. of butyl-lithium in hexane to a soln. of the alkyne in anhyd. ether at -30°C, stirring for 15 min under dry N2, addn. of a soln. of the trialkylchlorostannane in ether, stirring for 30 min, rising temp. to room temp. during 1h.; Addn. of light petroleum, filtration under a stream of dry N2, evapn., distn. at reduced pressure, elem. anal.;

in not given