n-butyllithium in diethyl ether; hexane BuLi soln. (hexane) addn. dropwise (stirring) into thiophene soln. (Et2O) at ca. -78°C, mixt. stirring 15 min at this temp., Sn-compd. soln. (Et2O) addn. dropwise at <-70°C, stirring 30 min, mixt. (roomtemp.) pouring onto ice, diln. (H2O); org. phase sepn., aq. phase extn. (Et2O), extracts washing (brine), drying (MgSO4), evapn., residue fractional distn.; elem. anal.;