GENERAL METHOD: To a solution of 4-bromoaniline (5.0 g, 29.1 mmol) in dichloromethane (DCM, 100 mL) was added 3,3-dimethylacryloyl chloride (3.40 mL, 30.6 mmol) to give a white suspension, which was stirred for 0.5 hours. Pyridine (9.70 mL, 30.6 mmol) was then added and the reaction mixture was stirred at room temperature for 16 hours. After completion of the reaction, it was diluted with DCM and water and washed with saturated aqueous NaHCO3. The organic layer was dried with MgSO4 and concentrated under reduced pressure to give a light brown crude solid (33 g). Recrystallization by hexane gave a white solid N-(4-bromophenyl)-3-methylbut-2-enamide (6.87 g, 94% yield). N-(4-bromophenyl)-3-methylbut-2-enamide (4.5 g, 17.7 mmol) and anhydrous AlCl3 (3.54 g, 26.6 mmol) were dissolved in anhydrous DCM (90 mL) under argon protection with vigorous stirring for 2.5 h at room temperature. The reaction mixture was cooled to 0 °C, the reaction was quenched by slow addition of water, diluted with DCM and stirred with 20% NaOH (w/v) until the solution turned off-white and further washed with water. The organic layer was dried with MgSO4 and concentrated under reduced pressure to give 6-bromo-4,4-dimethyl-1,2,3,4-tetrahydroquinolin-2-one (4.07 g, 90% yield). 6-Bromo-4,4-dimethyl-1,2,3,4-tetrahydroquinolin-2-one (4.07 g, 16.02 mmol) was dissolved in anhydrous DMF (50 mL), crushed KOH (2.70 g, 48.06 mmol) was added, and stirred for 1 h at 50 °C under argon protection. Subsequently, 2-iodopropane (4.8 mL, 48.06 mmol) was added and stirring was continued at 50 °C for 40 hours. After completion of the reaction, it was quenched with water, diluted with EtOAc and washed with saturated aqueous NaHCO3. The organic layer was dried with MgSO4 and concentrated under reduced pressure to give a crude clear oily substance. Purification by silica gel column chromatography (eluent: hexane/EtOAc 9:1 with 1% Et3N) afforded the colorless oil 6-bromo-4,4-dimethyl-1-(propan-2-yl)-1,2,3,4-tetrahydroquinolin-2-one (2.19 g, 46% yield).
