Structural Expansion of Dibenzo[,]thiophene Sulfone through Functionalization at Bay Positions.

We report a synthesis of 1,9-dibromodibenzo[,]thiophene sulfone, which was converted to a respective dilithio intermediate. Subsequent trapping with electrophiles afforded either 1-substituted (R = CHO, B(OH)) or 1,9-disubstituted (R = COH, I) derivatives, indicating an effect of steric factors on the outcome of this reaction. Various annulation reactions were also probed giving rise to extended π-conjugated systems. The electronic and optical properties of all compounds were characterized by cyclic voltammetry, UV-vis spectroscopy, and DFT calculations.