92-06-8

In a 25 mL two-necked flask under nitrogen protection, triethyl orthoformate (4.0 mmol), acetophenone (1.0 mmol), and THF (5 mL) were added. After stirring for 0.5 h, trifluoromethanesulfonic acid (0.1 mmol) was added to the mixture. The reaction was continuously monitored by TLC. After the reaction was completed, saturated sodium carbonate solution (10 mL) was added to quench the reaction, resulting in a two-phase solution, which was then extracted with dichloromethane (3 × 10 mL). The organic layer obtained from the extraction was dried with anhydrous sodium sulfate, concentrated by rotary evaporation under reduced pressure, and finally separated by silica gel column chromatography (using ethyl acetate-hexane as the eluent) to obtain 1,3-Diphenylbenzene IIa as a white solid with a yield of 61% and a melting point of 83-84 °C.