Dedicated to Professor Dieter Seebach on the occasion of his 65th birthdayThe title compounds were prepared starting from pyrrolinone 4. Nucleophilic-displacement and ringclosure 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(h 2 -C 2 H 4 ) (PPh 3 ) 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 Pt II complex 18 was prepared by an oxidative insertion of Pt 0 into the CÀS bond of the corresponding thiosulfonate 10b. Furthermore, complex 18 was characterized by single-crystal X-ray-diffraction studies.

Dedicated to Professor Heinrich Nˆth on the occasion of his 75th birthdayThe title compounds were prepared starting from the dihydropyrrolones 4 ± 6. Nucleophilic displacement and ring closure yielded the 1H-pyrrolo[3,2-c]isothiazol-5(4H)-ones 8 and 10. The fused systems formed salts with strong acids and electrophiles (15, 16), as well as with bases. Oxidation led either to S(2)-oxides (18a, 20a) or to the corresponding bicyclic sultams (18b, 20b), depending on the reaction conditions. The sulfinamide 18a was also obtained from the known 1,2-dithiolopyrrolone S-oxide 21 by a ring-opening/ring-closure reaction sequence. O-Methylation of 8 furnished the −azafulvene× 17. The oxidative addition of [Pt(h 2 -C 2 H 4 )L 2 ] (24a: L Ph 3 P, 24b: L 1/2 dppf, 24c: L 1/2 (R,R)-diop) to 18a and 20a led to the cis-amido-sulfenato Pt complexes 25 and 26a ± c, respectively.

Die Titelverbindungen 7‐9 reagieren mit Nucleophilen an der Lactimethergruppe, während bei 6 Umsetzungen in 4‐Stellung, bei der bromierten Verbindung 14 in 4‐ wie auch in 6‐Stellung möglich sind.

Aus den Benzyliden‐pyrrolinonen (I) werden die Lactimether (II) hergestellt; analog wird (IV) aus (III) erhalten.