Reaction Steps
To a stirred solution of 1,2-diphenylethylamine (930 mg, 4.20 mmol) in EtOH (30 ml) were added 3-bromo-1-propyne (700 mg, 5.30 mmol) and potassium carbonate (1.38 g, 10.0 mmol). The mixture was refluxed for 16 h and then more 3-bromo-1-propyne (100 rag) was added. The mixture was refluxed another 6 h and then it was cooled, diluted with 1N NaOH (200 ml) and extracted with CH2Cl2. The extract was dried (MgSO4) and concentrated. The residue was purified by flash chromatography. Elution with 1:1 hexanes-CH2Cl2 gave first N,N-di-propargyl-1,2-diphenylethylamine (218 mg, 19%) [1H NMR (CDCl3) δ2.34 (t, 2), 2.83 (dd, 1), 3.53 (dd, 1), 3.63 (dd, 2), 3.71 (dd, 2), 3.85 (dd, 1), 6.89-6.92 (m, 2), 7.14-7.26 (m, 8); 13C NMR (CDCl3) δ40.5 (t), 40.9 (t), 68.2 (d), 73.4 (d), 79.4 (d), 126.1, 127.6, 128.1, 128.3, 128.8, 129.7, 129.8 (all d), 138.8, 140.8 (all s)]followed by N-propargyl-1,2-diphenylethylamine. Distillation at 180° C./0.5 mm gave the pure compound (583 mg, 59%) as a colorless oil: 1H NMR (CDCl3) δ1.69 (bs, 1), 2.20 (t, 1), 2.95 (dd, 1), 3.06 (dd, 1), 3.24 (dd, 1), 3.36 (dd, 1), 4.21 (dd, 1), 7.25-7.50 (m, 10); 13C NMR (CDCl3) δ36.0 (t), 45.1 (t), 62.6 (d), 71.6 (d), 82.2 (s), 126.7, 127.6, 127.8, 128.7, 129.5 (all d), 138.6, 142.7 (all s).
