Reaction Steps
Prepared as described in Example 1 (System B) from methyl magnesium chloride 3M in tetrahydrofuran (7.3 ml, 21 mmol), (2E,4E)-nona-2,4-dienal (3 g, 21 mmol), dibromomethane (15 g, 87 mmol) and tert-butyl magnesium chloride 2M in diethyl ether (43 ml, 87 mmol) at 0°-10° C. Work-up after 18 h and bulb-to-bulb distillation at 80° C./0.05 mbar gave 3.1 g (77%) of a colorless oil (syn/anti=83:17). Odour: fruity, pear, green. 1H NMR (CDCl3): δ 1H NMR (CDCl3): δ 0.5 (m, 1H), 0.7 (m, 1H), 0.8-1 (2H), 0.9 (t, 3H), 1.2-1.4 (6H), 1.8-2.0 (3H), 3.2 (m, 1H), 5.0 (m, 1H), 5.5 (m, 1H) ppm. 13C-NMR (CDCl3) syn-isomer: δ 11.5 (t), 13.9 (q), 18.8 (d), 22.2 (d), 22.5 (q), 28.1 (d), 31.7 (t), 32.1 (t), 71.5 (d), 128.9 (d), 131.7 (d). 13C-NMR (CDCl3) anti-isomer: δ 10.8 (t), 14.0 (q), 19.6 (d), 22.2 (d), 22.5 (q), 28.3 (d), 31.7 (t), 32.1 (t), 72.0 (d), 128.7 (d), 132.0 (d). syn-configuration assigned by GC retention time. MS (EI): m/z (%) 168 ([M]+, 1), 150 ([M-H2O]+, 7), 113 (48), 95 (47), 82 (33), 81 (80), 68 (72), 67 (100), 57 (43), 55 (45), 54 (80), 45 (75), 43 (56), 41 (64). IR (film): 3340 (br, OH), 2958 (m), 2925 (m), 2871 (m), 2858 (m), 1455 (m), 1414 (w), 1366 (m), 1290 (w), 1180 (w), 1103 (m), 1076 (m), 1029 (m), 959 (s), 897 (m).
