The synthesis of the first fused [3,4]furano-TTFs has been accomplishe
d starting from the 4-formyl-5-diethoxymethyl-2-thioxo-1,3-dithiole. T
wo routes have been explored involving either the furan ring or the TT
F core. In particular, the first proceeds via the new [3,4]furano-2-th
ioxo-1,3-dithiole. (C) 1997 Published by Elsevier Science Ltd.