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.;

n-butyllithium; iodine 1) -70 deg C, hexane, 10 min, 2a) -70 deg C, 30 min, 2b) -30 deg C, 30 min; Yield given. Multistep reaction;

N-bromosuccinmide in acetic acid T=15 - 17°C; 2.5 h;

1: 1.) LDA / 1.) THF, hexane, -70 deg C, 1 h 2: 58 percent / n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 - -70 °C View Scheme