Metallation of the acetylenes MeCCR (R= CC–SiMe3, CCMe, CC–Sme, CC–Nalkyl2, S– CCSiMe3, S–CC–Me) with BuLi· ButOK, followed by the successive addition of carbon disulphide, t-butyl alcohol, and hexamethylphosphoric triamide gives thieno [2, 3,-b] thiophene, thieno-1, 4-dithi-ine, and some of their derivatives in reasonable yields.
