3.2.2. General Procedure for the Synthesis of Double Aza-oxa[7]helicene **3**

A 10 mL DCM solution of **2** (54 mg, 0.1 mmol), β-naphthol (57.7 mg, 0.4 mmol), tetrabutylammonium hexafluorophosphate(V) (387.4 mg, 1.0 mmol), and BF3OEt2 (0.2 M) was transferred into the undivided electrolysis cell of ElectraSyn® 2.0. This cell is equipped with two Pt electrodes connected to a DC power supply. At room temperature, a constant current of 1.5 mA was applied for 3.5 h. After the completion of reaction, the electrolysis was stopped and crude mixture was purified by column chromatography (SiO2, EtOAc/*n*hexane) to afford the double aza-oxa[7]helicene **3** as a yellow solid in 26% yield.
