Triflic Acid Mediated Cascade Cyclization of Aryldiynes for the Synthesis of Indeno[1,2-c]chromenes: Application to Dye-Sensitized Solar Cells

摘要

A new triflic acid (TfOH)-mediated cascade cyclization of ortho-anisole-substituted aryldiynes is described for the construction of indeno[1,2-c]chromenes. The cascade cyclization proceeds through an unusual TfOH-induced alkyne-alkyne cyclization followed by nucleophilic attack of the methoxy group on the benzylidene cation, which is completely different to the cyclization of ortho-aniline-or ortho-thioanisole-substituted aryldiynes. A new class of organic dyes with the indeno[1,2-c] chromene framework as both donor and pi-linker were synthesized. These compounds exhibit high photovoltaic performances in dye-sensitized solar cells (DSCs).