Stable 1H-Benzo[c]thio- and 1H-Benzo[c]selenophen-2-ium Tetrafluoroborates: Insight into Electronic Structures, Electrochemical Behavior, and Reactivity

Abstract

The synthesis of 1H-benzo[c]thio- and 1H-benzo[c]selenophen-2-ium tetrafluoroborates by the reaction of triphenylcarbenium tetrafluoroborate with 1-ethylidene-1,3-dihydrobenzo[c]thiophene or 1-ethylidene-1,3-dihydrobenzo[c]selenophene, respectively, is reported. The electronic structure of these novel 1H-benzo[c]chalcogenophenium salts was examined on the basis of their electronic spectra, whereby transitions were assigned in agreement with theoretical calculations. Electrochemical measurements revealed irreversible one-electron reduction waves for these 1H-benzo[c]chalcogenophenium salts.

Recent Advances in the Synthesis of Heterocycles via Reactions Involving Elemental Sulfur

“…Treatment of 43 with NaSH generated from the reduction of S 8 with NaBH 4 in DMF led to the corresponding sulfur heterocycles 44-45 in moderate yields (Scheme 16). [15] The reaction followed as sequence of nucleophilic sulfuration and cyclization. When substituted by a phenyl group, the product exists as benzylidene form 45, whereas aromatic form 44 is exclusive for t-butyl derivative.…”