1: 4-bromo-2-ethyl-5-(ethylthio)thiophene With n-butyllithium in diethyl ether; hexane T=-70°C; 0.5 h; 2: 1-(2-ethyl-5-ethylthio-3-thienyl)heptafluorocyclopent-1-ene in diethyl ether; hexane T=-70 - 20°C; 2 h;