First synthesis and structure of sulfur-containing heterocycles fused to ferrocene

Synthesis of a stable pentathiepin fused to a single cyclopentadienyl ring of ferrocene was performed by treatment of the corresponding dithiastannole as a synthetic equivalent of unstable ferrocene 1,2-dithiol with a sulfur source. On the other hand, deprotection of the dithiastannole gave a novel tetrathiocin comprised of two ferrocene units. The single-crystal X-ray diffraction studies revealed the unprecedented sulfur-containing heterocycles bound to ferrocene units.