Synthesis and Reactions of New Dithiolopyrroles

The title compounds were prepared starting from pyrrolinone 4. Nucleophilic-displacement and ring-closure reactions yielded the dithiolopyrrole 5a, which formed salts with electrophiles (7, 8) as well as with bases. The crystal structure of 5a was determined. Oxidation of the dithioles 5a and 6a led to S(2)-oxides (10a, 11a) and the corresponding S(2)-dioxides (10b, 11b) depending on reaction conditions. The thiosulfinate 10a was converted by a ring-opening/ring-closure reaction sequence to the bicyclic sulfinamide 12. The oxidative addition reactions of [Pt(η2-C2H4) (PPh3)2] (14) with the disulfides 5a and 13 led to the dithiolatoplatinum(II) complexes 15 and 16, respectively. Complex 16 was characterized structurally. The sulfenato-thiolato complex 17 was synthesized via reaction of 14 with the thiosulfinate 10a. The thiosulfonato PtII complex 18 was prepared by an oxidative insertion of Pt0 into the CS bond of the corresponding thiosulfonate 10b. Furthermore, complex 18 was characterized by single-crystal X-ray-diffraction studies.