Synthesis
General procedure for the synthesis of 1-bromo-2-methylnaphthalene from 1-bromo-2-methylnaphthalene: In an oven-dried vial (35x12 mm) fitted with a PTFE-sealed screw cap, a magnetic stir bar, ((+/-)-binap)Ni[P(OPh)3]2-2PhCH3 (39 mg, 25 μmol, 5 mol%), (+/-)- binap (15 mg, 25 μmol, 5 mol%) and the corresponding aryl halide (0.50 mmol, 1.0 equiv). Subsequently, the vial was transferred to an argon-filled glove box and NaOtBu (216 mg, 2.20 mmol, 4.40 eq.) and NH3 (0.5 M solution of 1,4-dioxane, 3.0 mL, 1.5 mmol, 3.0 eq.) were added sequentially. After sealing the reaction vial, it was removed from the glove box and placed in an oil bath preheated to 120 °C with stirring for 18 hours. After completion of the reaction, it was cooled to room temperature and the reaction mixture was diluted with Et2O (15 mL) and washed sequentially with 1 M NaOH (10 mL) and H2O (10 mL). The organic layer was adsorbed on silica gel and purified by fast column chromatography (eluent: EtOAc/hexane or EtOAc/MeOH) to obtain the target product aniline analogs. Specifically for the synthesis of 2-methylnaphthalen-1-amine (19k), 1-bromo-2-methylnaphthalene (84 μL, 0.50 mmol) was used as the starting material according to the general method described above and purified by fast column chromatography (eluent: Hexane/EtOAc 90:10) to afford the dark orange oily target compound 19k (73 mg, 0.46 mmol, 93% yield). The spectral data were in agreement with those reported in the literature [64]: Rf 0.20 (hexane/EtOAc 90:10); 1H NMR (CDCl3, 500 MHz) δ 7.85-7.80 (2H, m, 2Ar-H), 7.50-7.43 (2H, m, 2Ar-H), 7.33 (1H, d, J = 8.3 Hz, Ar-H), 7.28 (1H, d, J = 8.3 Hz, Ar-H), 4.11 (2H, br s, NH2), 2.38 (3H, s, CH3); 13C NMR (CDCl3, 125 MHz) δ 139.0 (Ar-C), 133.2 (Ar-C), 129.4 (Ar-CH), 128.6 (Ar-CH), 124.92 (Ar-CH), 124.92 (Ar-CH), 128.6 (Ar-CH), 124.92 (Ar-CH), 128.6 (Ar-CH), 128.6 (Ar-CH), 128.6 (Ar-CH), 124.9 (Ar-CH) 124.92 (Ar-CH), 124.87 (Ar-CH), 123.4 (Ar-C), 120.3 (Ar-CH), 118.3 (Ar-CH), 116.3 (Ar-CH), 17.8 (CH3).
References
[1] Australian Journal of Chemistry, 2015, vol. 68, # 12, p. 1842 - 1853
[2] Journal of Organic Chemistry, 2010, vol. 75, # 14, p. 4887 - 4890
