Reactions of arylthiazylamides with internal and external fluoro electrophiles - Formation of products with unusual structures

The heteroatom reactivity of the title anions [as (Me2N)(3)S+ and Cs+ salts ] toward both internal and external fluoro electrophiles has been investiga ted. The intramolecular nucleophilic cyclization of [ArNSN](-) (as the cesi um salts) bearing at least one ortho fluorine afforded 2,1,3-benzothiadiazo les (e.g. 2a,b), whereas intermolecular condensation with polyfluorinated p yridine and naphthalene afforded Ar-N=S=N-R with R = 4-Py-F (4) and R = 2-N p-F (8). Further interaction of [ArNSN](-) with 4 or 8 proceeded with the t ransfer of NSN units resulting in (ArN=)(2)S (5) and [RNSN](-), followed by de-composition (R = 4-Py-F) to 4-PyFNH2 (6) or intramolecular cyclization (R = 2-NpF) to the polyfluorinated thiadiazole 9. The compounds of types 4, 5, 8, and 9 have been characterized by single-crystal X-ray diffraction as having both Z,E and Z,Z configurations [8 and 9 as molecular complexes wit h C10F8 and (Ph-N=)(2)S (5e), respectively, featuring pi -stacking interact ions of the arene-polyfluoroarene type], Besides normal aryl-polyfluoroaryl interactions, the 8.C10F8 complex also displays unusual polyfluoroaryl-pol yfluoroaryl pi -stacking.