General procedure for the synthesis of 2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline from 2-methyl-4-bromoaniline and pinacol bis(boronic acid) ester: To a solution of 2-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (1.05 g, 0.134 mmol) containing 4-bromo-2-methylaniline (500 mg, 2.69 mmol), potassium acetate (1.32 g, 13.4 mmol) and bis(pinacolato)diboron ( 2.05 g, 8.0 mmol) to a solution of dioxane (4 mL) was added Pd(dppf)Cl2 (110 mg, 0.134 mmol). After degassing and replacement with nitrogen, the reaction mixture was refluxed for 16 h at 85 °C. The progress of the reaction was monitored by thin layer chromatography (TLC) and after confirming the completion of the reaction, water (20 mL) was added and the mixture was extracted with ethyl acetate (30 mL x 3). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated, and finally purified by silica gel column chromatography (eluent: dichloromethane) to afford the target compound 13-2 as a white solid (485 mg, 77% yield).
