Synthesis of 3-phenylcyclohex-2-enone (1an). To an oven-dry three-necked flask were added Mg chips (1.3 equiv.) and half a grain of I2. The flask was evacuated and flushed with nitrogen gas for three times. Anhydrous THF was added (1.0 M) and the mixture was heated to 65 °C. One-third of bromobenzene solution (1.0 M in anhydrous THF) was added. When the color of the reaction solution turned from yellow to pale yellow, the rest of bromobenzene solvent was added drop-wise for 15 min whilst the reaction mixture was heated to micro-boiling. The reaction was stirred at 65 °C until the complete consumption of Mg chips. Subsequently, a solution of S6