Helvetica Chimica Acta ± Vol. 83 (2000)
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(90.6 MHz, CDCl3): 194.77 (s); 161.48 (s); 131.49 (s); 124.41 (d); 64.86 (t); 39.38 (t); 36.93 (t); 35.20 (t); 31.96 (t);
29.68 (3Â) (t); 29.61 (t); 29.45 (2Â) (t); 29.39 (t); 29.33 (t); 29.01 (t); 25.71 (q); 25.37 (t); 23.05 (t); 22.71 (t);
19.38 (q); 17.66 (q); 14.12 (q). EI-MS: 225 (11), 183 (14), 155 (8), 139 (7), 138 (55), 137 (28), 124 (6), 123 (52),
121 (5), 111 (4), 110 (7), 109 (27), 97 (9), 96 (16), 95 (70), 94 (8), 85 (16), 83 (28), 82 (50), 81 (97), 80 (10), 71
(26), 70 (11), 69 (100), 68 (11), 67 (21), 57 (54), 56 (12), 55 (47), 43 (48), 42 (10), 41 (55), 39 (7), 29 (12).
(Æ)-3,7-Dimethyloct-6-enyl 3-Methyl-2-oxopentadecanoate ((Æ)-8). As described above (MethodB ) with
5.0 g (18 mmol) of 2-bromotetradecane, 0.58 g (24 mmol) of Mg and 7.32 g (20 mmol) of (Æ)-6 in 50 ml of THF.
CC (3Â) (SiO2; heptane/Et2O 95 :5): 2.52 g (34%) of (Æ)-8. Colorless oil. Rf(heptane/Et2O 95 :5) 0.46. UV/VIS
(hexane): 394 (sh, 4), 383 (sh, 10), 373 (sh, 10), 365 (sh, 20), 349 (sh, 20), 336 (20), 284 (sh, 10), 269 (sh, 20), 241
(sh, 140). IR (neat): 3440w, 2958s, 2924s, 2854s, 2730w, 1749s, 1725s, 1460m, 1378m, 1350w, 1266m, 1173w, 1146w,
1112w, 1053m, 1032m, 943w, 887w, 830w. 1H-NMR (360 MHz, CDCl3): 5.13 ± 5.04 (m, 1 H); 4.36 ± 4.23 (m, 2 H);
3.23 ± 3.10 (m, 1 H); 2.10 ± 1.87 (m, 2 H); 1.87 ± 1.64 (m, 1 H); 1.68 (s, 3 H); 1.64 ± 1.47 (m, 2 H); 1.60 (s, 3 H);
1.46 ± 1.16 (m, 24 H); 1.13 (d, J 6.7, 3 H); 0.94 (d, J 6.3, 3 H); 0.88 (t, J 6.9, 3 H). 13C-NMR (90.6 MHz,
CDCl3): 198.33 (s); 162.20 (s); 131.50 (s); 124.40 (d); 64.75 (t); 42.21 (d); 36.93 (t); 35.23 (t); 31.92 (t); 29.68 (t);
29.66 (2Â) (t); 29.59 (2Â) (t); 29.45 (2Â) (t); 29.37 (t); 27.01 (t); 25.71 (q); 25.37 (t); 22.70 (t); 19.35 (q); 17.66
(q); 15.01 (q); 14.12 (q). EI-MS: 408 (1, M ), 255 (4), 197 (3), 183 (12), 155 (8), 141 (4), 139 (9), 138 (76), 137
(21), 127 (7), 123 (46), 113 (9), 109 (19), 99 (15), 96 (15), 95 (57), 94 (8), 85 (47), 83 (25), 82 (52), 81 (89), 80
(14), 71 (65), 70 (10), 69 (100), 68 (10), 67 (18), 57 (94), 56 (17), 55 (51), 43 (61), 41 (69), 39 (7), 29 (15), 27 (6).
(Æ)-3,7-Dimethyloct-6-enyl 2-Oxo-2-phenylacetate ((Æ)-9; for an alternative synthesis, see [27]). As
described above (MethodB ) with 3.14 g of 1-bromobenzene (20 mmol), 0.55 g of Mg (22 mmol) in 20 ml of
Et2O, and 8.0 g (22 mmol) of (Æ)-6 in 50 ml of Et2O. CC (SiO2; heptane/Et2O 95 :5) allowed a partial separation
of the product from remaining 6. MPLC on a Lobar column (SiO2 (Merck); heptane/Et2O 97:3) finally afforded
3.5 g (61%) of pure (Æ)-9. Bright yellow oil. Rf(heptane/Et2O 97 :3) 0.16. UV/VIS (hexane): 370 (sh, 30), 352
(40), 340 (sh, 40), 294 (sh, 1020), 252 (10350), 248 (10360). IR (neat): 3065w, 2962s, 2926s, 2872m, 2855m, 1738s,
1693s, 1597m, 1581m, 1451m, 1379m, 1322m, 1313m, 1300m, 1246w, 1198s, 1175s, 1122w, 1042w, 1030w, 1003m,
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998m, 941w, 831w. H-NMR (360 MHz, CDCl3): 8.04 ± 7.97 (m, 2 H); 7.69 ± 7.62 (m, 1 H); 7.55 ± 7.45 (m, 2 H);
5.12 ± 5.03 (m, 1 H); 4.50 ± 4.36 (m, 2 H); 2.15 ± 1.90 (m, 2 H); 1.90 ± 1.75 (m, 1 H); 1.75 ± 1.50 (m, 2 H); 1.66
(s, 3 H); 1.59 (s, 3 H); 1.45 ± 1.32 (m, 1 H); 1.32 ± 1.15 (m, 1 H); 0.96 (d, J 6.3, 3 H). 13C-NMR (90.6 MHz,
CDCl3): 186.50 (s); 164.02 (s); 134.87 (d); 132.56 (s); 131.51 (s); 130.02 (d); 128.90 (d); 124.40 (d); 64.85 (t);
36.93 (t); 35.30 (t); 29.44 (d); 25.69 (q); 25.38 (t); 19.38 (q); 17.66 (q). EI-MS: 288 (1, M ), 270 (4), 155 (4), 152
(3), 138 (9), 137 (10), 123 (11), 109 (8), 106 (10), 105 (100), 96 (3), 95 (20), 83 (3), 82 (12), 81 (24), 78 (3), 77 (36),
70 (3), 69 (26), 68 (5), 67 (10), 57 (3), 56 (3), 55 (11), 53 (3), 51 (10), 43 (4), 42 (3), 41 (28), 39 (5), 29 (4), 27 (4).
2-(4-Bromomethyl)-2-methyl-1,3-dioxolane (33) [38]. 4-Bromoacetophenone (10.0 g, 50 mmol), 7.0 g
(112 mmol) of ethylene glycol, and a few crystals of TsOH were dissolved in 100 ml of toluene, and the
mixture was heated overnight under reflux with azeotropic removal of H2O. After cooling to r.t., the mixture
was concentrated in vacuo. CC (SiO2; heptane/Et2O 9 :1) afforded 11.4 g (93%) of a colorless oil, which easily
crystallized. Rf(heptane/Et2O 9 :1) 0.39. UV/VIS (hexane): 287 (sh, 400), 274 (sh, 1300), 270 (sh, 1800), 259
(sh, 6700), 252 (7800), 227 (sh, 61800), 220 (75600), 217 (sh, 75000). IR (neat): 3084w, 3060w, 2990m, 2957s,
2928s, 2890s, 2856m, 2670w, 1911w, 1691m, 1657w, 1591m, 1575w, 1482m, 1470w, 1443m, 1393m, 1373m, 1249m,
1222w, 1196s, 1144m, 1118m, 1092m, 1079m, 1040s, 1010s, 947m, 873s, 826s. 1H-NMR (360 MHz, CDCl3): 7.49 ±
7.42 (m, 2 H); 7.39 ± 7.32 (m, 2 H); 4.08 ± 3.96 (m, 2 H); 3.80 ± 3.69 (m, 2 H); 1.62 (s, 3 H). 13C-NMR (90.6 MHz,
CDCl3): 142.49 (s); 131.30 (d); 127.17 (d); 121.86 (s); 108.43 (s); 64.47 (t); 27.52 (q). EI-MS: 244, 242 (1, 1, M ),
230 (14), 229 (97), 227 (100), 213 (5), 211 (5), 186 (4), 185, 183 (51, 53), 157, 155 (14, 14), 148 (4), 133 (5), 104
(8), 103 (9), 102 (8), 89 (3), 87 (26), 77 (12), 76 (16), 75 (14), 74 (7), 63 (4), 51 (7), 50 (13), 43 (41), 39 (3), 29 (7).
(Æ)-3,7-Dimethyloct-6-enyl [4-(2-Methyl-1,3-dioxolan-2-yl)phenyl]-2-oxoacetate ((Æ)-34). As described
above (MethodB ) with 4.66 g (20 mmol) of 33, 0.54 g (22 mmol) of Mg, and 8.0 g (22 mmol) of 6 in 50 ml of
THF. CC (SiO2; heptane/Et2O 8 :2): 4.35 g (58%) of (Æ)-34. Slightly yellow oil. Rf(heptane/Et2O 8 :2) 0.25. UV/
VIS (hexane): 370 (sh, 40), 353 (60), 340 (sh, 60), 296 (sh, 1300), 258 (13890). IR (neat): 2963s, 2926s, 1736s,
1690s, 1607s, 1573m, 1505w, 1455m, 1407m, 1374m, 1347w, 1314m, 1294w, 1250m, 1199s, 1175s, 1146w, 1122w,
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1100w, 1078m, 1039m, 1018w, 989m, 948w, 890w, 876m, 861m, 833w. H-NMR (360 MHz, CDCl3): 7.98 (d, J
8.3, 2 H); 7.62 (d, J 8.7, 2 H); 5.12 ± 5.04 (m, 1 H); 4.50 ± 4.36 (m, 2 H); 4.13 ± 4.00 (m, 2 H); 3.82 ± 3.70
(m, 2 H); 2.10 ± 1.90 (m, 2 H); 1.90 ± 1.75 (m, 1 H); 1.72 ± 1.54 (m, 2 H); 1.67 (s, 3 H); 1.65 (s, 3 H); 1.60 (s, 3 H);
1.45 ± 1.32 (m, 1 H); 1.30 ± 1.16 (m, 1 H); 0.96 (d, J 6.3, 3 H). 13C-NMR (90.6 MHz, CDCl3): 186.04 (s); 163.97
(s); 150.64 (s); 132.12 (s); 131.53 (s); 130.15 (d); 125.97 (d); 124.39 (d); 108.39 (s); 64.89 (t); 64.65 (2Â) (t); 36.93
(t); 35.30 (t); 29.44 (d); 27.38 (q); 25.70 (q); 25.37 (t); 19.38 (q); 17.66 (q). EI-MS: 374 (7, M ), 359 (8), 356 (3),