Synthesen und Reaktionen acyclischer fluororganischer Thiocarbenium‐Ionen

Syntheses and Reactions of Fluoroorganic Acyclic Thiocarbenium Ions Herrn Prof. Dr. W. Sawodny zum 60. Geburtstag gewidmet. Arsenic pentafluoride oxidizes (F3CS)4C (1) but not (F3CS)2C = C(SCF3)2 (2) to yield the stable salt (F3CS)3C+AsF‐6 (3). It reacts with halide ions to form (F3CS)3CX (3a–c, X = F, Cl, Br). Iodide is oxidized to iodine with formation of (F3CS)3CC(SCF3)3 (4) which reacts with nitrogen dioxide to give (F3CS)3CNO2 (3e). ‐ (F3CS)3C+AsF‐6 (3) removes from (F)‐SCF3 (5a) a ring‐bound fluorine atom to afford (F3CS)3CF and magnified image ‐SCF3]+AsF−6 (5). When (F3CS)3CCl (3b) is treated with AsF5, 3 and [(F3CS)2‐CCl]+AsF−6 (6) are formed in a 2:1 molar ratio. The latter reacts with F− or Cl− to give (F3CS)2CClX (6a,b; X = F, Cl). AsF5 is capable of abstracting a fluoride ion from (F3CS)3 ‐ n Cln,CF only if n = 0 or 1. For n = 2 no similar reaction takes place, but with AlCl3 in BCl3 halogen exchange to F3CSCCl3 (7b) is observed. ‐ Alkylation of (F3CS)2CS (8) with H3CF/AsF5 yields [(F3CS)2CSCH3]+AsF−6 (9), which adds a fluoride ion to give (F3CS)2(H3CS)CF (9a). The molecular structures of (F3CS)2C = C(SCF3)2 (2) and (F3CS)3CC(SCF3)3 (4) have been determined by X‐ray diffraction methods.