The general procedure for the synthesis of 2-isobutyl-5-nitrobenzonitrile from isobutylboronic acid and 2-bromo-5-nitrobenzonitrile was as follows: isobutylboronic acid (5.89 g), 2-bromo-5-nitrobenzonitrile (12.5 g), and Cs2CO3 (35.9 g) were dissolved in a solvent mixture of toluene (150 mL) and water (5 mL) under the protection of nitrogen and stirred at room temperature. Subsequently, PdCl2(dppf)-CH2Cl2 adduct (2.248 g) was added all at once. The reaction mixture was stirred at 100 °C for 16 hours. After completion of the reaction, it was cooled to room temperature and the solvent was removed by distillation under reduced pressure. The residue was purified by column chromatography to afford the target product 2-(2-methylpropyl)-5-nitrobenzonitrile (D42) (11 g) as a light yellow oil.1H NMR (CDCl3, 400 MHz) δ: 1.00 (6H, d), 2.06 (1H, m), 2.86 (2H, d), 7.52 (1H, d), 8.37 (1H, dd), 8.51 (1H, dd). dd), 8.51 (1H, d).
