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(10), 107 (11), 93 (2), 83 (18), 73 (100), 55 (14); HRMS (EI, ICP,
m/z) calcd for C20H32Si 300.2273, found 300.2260; IR (film, cm−1)
3079, 2918, 2861, 2728, 1768, 1643, 1604, 1550, 1489, 1448, 1407,
1379, 1330, 1248, 1179, 1119, 1021, 896, 837, 759, 713, 688, 646.
2-(4,5-Dimethyl-2-methylenehex-4-enyl)-3′-methoxy-4,5-dime-
thylbiphenyl (8f): colorless oil; 136 mg (0.41 mmol, 81%); eluent,
(75 MHz, CDCl3) δ 143.0, 141.4, 137.9, 136.4, 135.9, 133.2, 130.0,
129.5, 129.4, 127.3, 126.7, 126.3, 124.2, 112.8, 52.1, 50.5, 38.6, 21.5,
20.5, 20.3, 19.6, 19.4, 18.4; MS (EI) m/z (%) 411 (M+, 6), 292 (9),
256 (86), 240 (9), 225 (1), 212 (1), 184 (10), 171 (1), 155 (13), 136
(21), 119 (100), 107 (14), 91 (32), 77 (5), 65 (4), 53 (1); HRMS (EI,
ICP, m/z) calcd for C25H33NO2S 411.2232, found 411.2232; IR (film,
cm−1) 2921, 2860, 1649, 1598, 1505, 1448, 1341, 1305, 1215, 1160,
1119, 1094, 1072, 1020, 909, 815, 778, 752, 735, 708, 693, 656, 600,
547.
General Procedure for the Tandem Diels−Alder/1,4-Hydro-
vinylation Sequence with 2-(Trimethylsilyloxy)buta-1,3-diene.
Zinc iodide (20 mol %), zinc powder (20 mol %), and CoBr2(1,2-
bis(diphenylphosphino)ethane) (10 mol %) were suspended in
dichloromethane (1 mL) under argon atmosphere. Then 2-
(trimethylsilyloxy)buta-1,3-diene (2.4 mmol) and the enyne 7 (1.0
mmol) were added, and the mixture was stirred at room temperature
for 16 h. Afterward, the suspension was filtered over a short pad of
silica gel, and the solvent was removed under vacuum. The residue was
dissolved in tetrahydrofuran (8 mL) and was treated with aqueous
HCl (2 mL, 2 M). The mixture was stirred for 1 h at room
temperature and was then filtered over a short pad consisting of a silica
gel/MgSO4 mixture. The solvent was removed in vacuo, and the
residue was purified by flash column chromatography.
Methyl 2-(2-Methylene-5-oxohexyl)-4-oxocyclohex-1-enecarbox-
ylate (9a): pale yellow oil; 159 mg (0.60 mmol, 60%); eluent, diethyl
ether; 1H NMR (300 MHz, CDCl3) δ 4.78 (s, 1H), 4.73 (s, 1H), 3.71
(s, 3H), 3.36 (s, 2H), 3.18 (s, 2H), 2.62 (td, J = 7.5, 2.1 Hz, 2H), 2.51
(t, J = 6.4 Hz, 2H), 2.42−2.38 (m, 2H), 2.26 (t, J = 7.4 Hz, 2H), 2.15−
2.14 (m, 3H); 13C NMR (75 MHz, CDCl3) δ 208.7, 207.9, 166.7,
148.9, 145.1, 123.4, 111.3, 51.6, 41.7, 41.0, 40.7, 37.5, 30.1, 29.9, 29.6;
MS (EI) m/z (%) 264 (M+, 2), 249 (7), 232 (29), 215 (8), 204 (4),
193 (100), 175 (42), 161 (21), 147 (36), 133 (22), 119 (25), 105
(31), 91 (29), 77 (17), 65 (8), 55 (6); HRMS (EI, ICP, m/z) calcd for
C15H20O4 264.1362, found 264.1366; IR (film, cm−1) 3417, 3079,
2952, 2905, 2844, 1716, 1642, 1435, 1361, 1322, 1233, 1190, 1162,
1095, 1058, 1022, 995, 953, 896, 847, 766, 634, 589.
1
pentane/diethyl ether = 10:1; H NMR (300 MHz, CDCl3) δ 7.29−
7.23 (m, 1H), 7.04 (d, J = 5.3 Hz, 2H), 6.90−6.85 (m, 3H), 4.76 (s,
1H), 4.51 (s, 1H), 3.81 (s, 3H), 3.17 (s, 2H), 2.64 (s, 2H), 2.29 (s,
6H), 1.64 (s, 3H), 1.52 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 159.2,
147.9, 143.2, 139.7, 135.4, 134.1, 134.0, 131.6, 131.1, 128.7, 126.1,
125.0, 121.7, 114.8, 112.2, 111.4, 55.2, 41.5, 39.4, 20.5, 20.3, 19.4, 19.3,
18.3; MS (EI) m/z (%) 334 (M+, 65), 319 (23), 304 (1), 291 (48),
276 (22), 263 (18), 250 (100), 236 (45), 223 (39), 210 (16), 195
(16), 178 (16), 165 (18), 152 (9), 141 (2), 128 (3), 107 (9), 91 (4),
79 (4), 67 (4), 55 (6); HRMS (EI, ICP, m/z) calcd for C24H30O
334.2297, found 334.2284; IR (film, cm−1) 3442, 2917, 1643, 1600,
1580, 1481, 1452, 1430, 1385, 1315, 1286, 1240, 1212, 1179, 1117,
1051, 1021, 985, 892, 859, 781, 753, 734, 703.
2-(2-(5, 6-Dimethyl-3-methylenehept-5-enyl)-4, 5-
dimethylphenyl)thiophene (8g): colorless oil; 110 mg (0.34 mmol,
1
68%); eluent, pentane; H NMR (300 MHz, CDCl3) δ 7.31 (dd, J =
5.3, 1.1 Hz, 1H), 7.17 (s, 1H), 7.08−7.06 (m, 2H), 7.00 (dd, J = 3.4,
1.1 Hz, 1H), 4.71 (s, 1H), 4.66 (s, 1H), 2.84−2.79 (m, 2H), 2.71 (s,
2H), 2.29 (s, 3H), 2.26 (s, 3H), 2.19−2.14 (m, 2H), 1.68 (s, 3H), 1.62
(s, 3H), 1.57 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 147.5, 142.9,
138.0, 136.5, 134.0, 132.3, 131.2, 131.0, 126.9, 126.0, 125.9, 125.2,
124.8, 109.5, 41.4, 37.8, 31.9, 20.6, 20.4, 19.4, 19.1, 18.3; MS (EI) m/z
(%) 324 (M+, 24), 281 (7), 254 (3), 239 (8), 225 (2), 213 (4), 201
(100), 186 (31), 171 (19), 152 (3), 141 (4), 123 (5), 109 (1), 93 (2),
81 (2), 67 (1), 55 (2); HRMS (EI, ICP, m/z) calcd for C22H28S
324.1912, found 324.1924; IR (film, cm−1) 3073, 2919, 2861, 2727,
1785, 1643, 1495, 1451, 1384, 1372, 1264, 1225, 1192, 1151, 1103,
1076, 1021, 886, 847, 830, 734, 694, 659.
2-(5,6-Dimethyl-3-methylenehept-5-enyl)-4′-methoxy-4,5-dime-
thylbiphenyl (8h): colorless oil; 173 mg (0.50 mmol, 99%); eluent,
1
pentane/diethyl ether = 20:1; H NMR (300 MHz, CDCl3) δ 7.24−
3-(3-Methylene-6-oxoheptyl)-4-(thiophen-2-yl)cyclohex-3-enone
(9b): orange oil; 70 mg (0.23 mmol, 46%); eluent, pentane/diethyl
7.22 (m, 2H), 7.06 (s, 1H), 7.00 (s, 1H), 6.95−6.92 (m, 2H), 4.63 (s,
1H), 4.61 (s, 1H), 3.86 (s, 3H), 2.71−2.67 (m, 2H), 2.64 (s, 2H), 2.30
(s, 3H), 2.27 (s, 3H), 2.12−2.06 (m, 2H), 1.67 (s, 3H), 1.59 (s, 3H),
1.53 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 158.4, 147.6, 139.0,
137.2, 135.3, 134.3, 133.8, 131.6, 130.6, 130.2, 125.8, 125.2, 113.4,
109.4, 55.3, 41.3, 37.7, 31.6, 20.6, 20.4, 19.4, 19.2, 18.2; MS (EI) m/z
(%) 348 (M+, 27), 305 (4), 278 (3), 263 (18), 250 (2), 237 (3), 225
(100), 210 (59), 195 (29), 179 (11), 165 (10), 152 (7), 115 (1), 93
(2), 79 (1), 67 (1), 55 (1); HRMS (EI, ICP, m/z) calcd for C25H32O
348.2453, found 348.2446; IR (film, cm−1) 2917, 2862, 1643, 1608,
1570, 1495, 1448, 1378, 1287, 1241, 1175, 1107, 1035, 965, 885, 832,
646, 564, 523, 488, 413.
1
ether = 1:1; H NMR (300 MHz, CDCl3) δ 7.27−7.24 (m, 1H),
7.02−6.98 (m, 1H), 6.88−6.85 (m, 1H), 4.74−4.66 (m, 2H), 3.20 (s,
1H), 3.01 (s, 1H), 2.80 (t, J = 6.8 Hz, 1H), 2.59−2.49 (m, 5H), 2.45−
2.32 (m, 2H), 2.25−2.10 (m, 7H); 13C NMR (75 MHz, CDCl3) δ
209.9, 209.5, 147.3, 142.9, 136.9, 133.5, 126.8, 125.3, 124.5, 109.8,
46.2, 43.9, 41.7, 38.6, 38.3, 34.7, 32.5, 29.5; MS (EI) m/z (%) 302
(M+, 20), 284 (3), 269 (2), 256 (3), 244 (7), 231 (9), 215 (4), 203
(4), 191 (100), 178 (7), 163 (16), 149 (19), 134 (13), 115 (10), 97
(11), 77 (5), 65 (4), 55 (5); HRMS (EI, ICP, m/z) calcd for
C18H22O2S 302.1341, found 302.1349; IR (film, cm−1) 3411, 3076,
2922, 2853, 2253, 1716, 1646, 1625, 1578, 1432, 1359, 1297, 1238,
1196, 1162, 1082, 1050, 964, 895, 842, 702, 588, 525.
Ethyl 2-((4,5-dimethyl-2-methylenehex-4-enyloxy)methyl)-4,5-di-
methylbenzoate (8i): colorless oil; 151 mg (0.46 mmol, 46%); eluent,
pentane/diethyl ether = 10:1; 1H NMR (300 MHz, CDCl3) δ 7.72 (s,
1H), 7.47 (s, 1H), 5.09 (s, 1H), 4.88 (s, 1H), 4.85 (s, 2H), 4.32 (q, J =
7.2 Hz, 2H), 3.98 (s, 2H), 2.82 (s, 2H), 2.31−2.25 (m, 6H), 1.68 (s,
3H), 1.66 (s, 3H), 1.62 (s, 3H), 1.38 (t, J = 7.2 Hz, 3H); 13C NMR
(75 MHz, CDCl3) δ 167.2, 144.3, 141.4, 138.5, 135.0, 131.5, 128.8,
126.4, 125.6, 124.6, 111.6, 73.5, 69.8, 60.6, 38.4, 20.6, 20.4, 20.0, 19.2,
18.4, 14.3; MS (EI) m/z (%) 330 (M+, 1), 251 (5), 223 (2), 207 (6),
191 (28), 177 (7), 163 (100), 146 (25), 133 (9), 121 (13), 107 (40),
91 (19), 79 (13), 67 (5), 55 (6); HRMS (ESI, FT-ICR, m/z) calcd for
C21H30O3Na 353.2087, found 353.2101; IR (film, cm−1) 2981, 2919,
2860, 1713, 1650, 1615, 1565, 1052, 1449, 1385, 1367, 1301, 1267,
1230, 1190, 1137, 1097, 1050, 902, 782, 631.
4-((2-Methylene-5-oxohexyloxy)methyl)cyclohex-3-enone (9c):
yellow oil; 110 mg (0.47 mmol, 47%); eluent, diethyl ether; 1H
NMR (300 MHz, CDCl3) δ 5.73 (s, 1H), 5.02 (s, 1H), 4.87 (s, 1H),
3.89 (s, 4H), 2.88 (s, 2H), 2.66−2.59 (m, 2H), 2.52−2.48 (m, 4H),
2.33 (t, J = 7.4 Hz, 2H), 2.15 (s, 3H); 13C NMR (75 MHz, CDCl3) δ
210.0, 207.9, 144.6, 135.6, 121.1, 112.0, 73.2, 73.0, 41.6, 39.3, 38.3,
29.8, 26.9, 26.0; MS (EI) m/z (%) 236 (M+, 1), 178 (1), 160 (1), 125
(10), 111 (100), 97 (32), 79 (62), 53 (25); HRMS (ESI, FT-ICR, m/
z) calcd for C14H20O3Na 259.1305, found 259.1308; IR (film, cm−1)
3465, 3080, 2918, 2852, 1716, 1654, 1424, 1359, 1230, 1192, 1161,
1086, 1051, 962, 903, 809, 783, 589.
4-Methyl-N-(2-methylene-5-oxohexyl)-N-((4-oxocyclohex-1-
enyl)methyl)benzene-sulfonamide (9d): colorless oil; 180 mg (0.46
1
mmol, 46%); eluent, diethyl ether; H NMR (300 MHz, CDCl3) δ
N-(4,5-Dimethyl-2-methylenehex-4-enyl)-N-(3,4-dimethylbenzyl)-
4-methylbenzene Sulfonamide (8j): colorless oil; 268 mg (0.65
7.68 (d, J = 8.3 Hz, 2H), 7.30 (d, J = 7.9 Hz, 2H), 5.56 (s, 1H), 4.86
(s, 1H), 4.84 (s, 1H), 3.70 (s, 4H), 2.82−2.81 (m, 2H), 2.54 (t, J = 7.4
Hz, 2H), 2.42 (s, 3H), 2.41−2.34 (m, 4H), 2.23−2.18 (m, 2H), 2.13
(s, 3H); 13C NMR (75 MHz, CDCl3) δ 209.5, 207.4, 143.5, 143.1,
136.7, 133.8, 129.7, 127.3, 123.2, 113.9, 53.2, 53.1, 41.3, 39.3, 38.1,
29.8, 26.9, 26.3, 21.5; MS (EI) m/z (%) 389 (M+, 1), 281 (1), 263 (5),
1
mmol, 70%); eluent, pentane/diethyl ether = 10:1; H NMR (300
MHz, CDCl3) δ 7.72 (d, J = 8.3 Hz, 2H), 7.29 (d, J = 7.9 Hz, 2H),
6.84 (d, J = 7.6 Hz, 1H), 6.99 (d, J = 7.6 Hz, 1H), 6.80 (s, 1H), 4.77
(s, 1H), 4.73 (s, 1H), 4.28 (s, 2H), 3.68 (s, 2H), 2.55 (s, 2H), 2.43 (s,
3H), 2.20 (s, 3H), 2.14 (s, 3H), 1.64 (s, 3H), 1.49 (s, 6H); 13C NMR
8382
dx.doi.org/10.1021/jo301028b | J. Org. Chem. 2012, 77, 8375−8385