[Synthesis]
A hexane solution (0.10 mL, 0.10 mmol) of 1.0 M AIMe2Cl was sequentially added to a 10 mL Schlenk tube containing Ni(COD)2 (6.9 mg, 5 mol%) and DPEphos (65 μL, 0.50 mmol) in an argon-protected glove box using isovaleronitrile (0.26 mL, 2.50 mmol) and 2-methylstyrene (65 μL, 0.50 mmol). 13.5 mg, 5 mol%) in a 10 mL Schlenk tube containing Ni(COD)2 (6.9 mg, 5 mol%) and DPEphos (13.5 mg, 5 mol%) in toluene solution (1.0 mL). The Schlenk tube was removed from the glove box, connected to a continuous stream of argon gas (positive pressure: 0.4 bar), and the reaction was heated at 100 °C for 16 hours. After completion of the reaction, it was cooled to room temperature and the reaction mixture was analyzed by gas chromatography (GC) to determine the regioselectivity based on the peak area ratio (1/b: 86/14). The reaction mixture was concentrated under reduced pressure and the residue was purified by fast column chromatography on silica gel (eluent: pentane/methyl tert-butyl ether=10/1) to afford the target products 2-(o-tolyl)propiononitrile (linear product: 57.3 mg, yield: 79%) and 2-methylbenzene propiononitrile (branched product: 9.4 mg). 1H NMR (500 MHz, CDCl3) δ of linear product: 7.23-7.14 (m, 4H), 2.98 (t, J=7.7 Hz, 2H), 2.59 (t, J=7.7 Hz, 2H), 2.34 (s, 3H); 13C NMR (125 MHz, CDCl3) δ: 136.34, 135.91, 130.78, 128.84, 127.50, 126.62, 119.35, 29.01, 19.30, 18.14. 1H NMR (500 MHz, CDCl3) δ of branched product: 7.45 (dd, J=7.3, 1.7 Hz, 1H), 7.29-7.17 (m, 3H), 4.05 (q, J=7.2 Hz, 1H). 7.2 Hz, 1H), 2.37 (s, 3H), 1.61 (d, J=1.2 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ: 135.38, 134.90, 131.12, 128.26, 127.13, 126.84, 121.94, 28.30, 20.18, 19.15. The spectral data of the obtained products are in agreement with literature reports. |