2960, 2929, 2875, 1720 (CO), 1601, 1451, 1383, 1275, 1213,
1175, 1113, 1070, 1026, 987 cm−1; H (500 MHz; CDCl3) 8.04 (2H,
d, J = 8.5 Hz, Ar–H), 7.55 (1H, m, Ar–H), 7.44 (2H, t, J = 7.5 Hz,
Ar–H), 4.31 (1H, dd, J = 11.0, 6.5 Hz, 1-HH), 4.14 (1H, dd, J = 11.0,
7.5 Hz, 1-HH), 3.54 (1H, dt, J = 8.0, 4.5 Hz, 5-H), 2.04 (1H, m, 2-H),
1.81 (1H, m, 3-H), 1.69–1.60 (2H, m’s, 4-HH and 6-H), 1.29 (1H,
ddd, J = 14.5, 8.0, 7.5 Hz, 4-HH), 1.03 (3H, d, J = 7.0 Hz, 8-H3), 1.01
(3H, d, J = 7.0 Hz, 9-H3), 0.93 [3H, d, J = 7.0 Hz, CH(CH3)2], 0.87
[3H, d, J = 7.0 Hz, CH(CH3)2]; C (126 MHz; CDCl3) 166.69 (CO),
132.86 (Ar), 130.57 (ipso-Ar), 129.51 (Ar), 128.35 (Ar), 75.04 (5-C),
67.38 (1-C), 37.95 (4-C), 36.31 (2-C), 33.13 (6-C), 32.66 (3-C),
19.09 [CH(CH3)2], 17.31 (9-C), 16.08 [CH(CH3)2], 14.62 (8-C); m/z
(ES+) 579 (M2Na+, 3%), 301 (M + Na+, 100%); HRMS (CI) Found
MNa+, 301.1779; C17H26O3Na requires MNa, 301.1780.
H (500 MHz; CDCl3) 4.22 (1H, dt, J = 11.0, 5.0 Hz, 6-H), 2.49
(1H, qd, J = 7.0, 5.0 Hz, 3-H), 2.12 (1H, m, 4-H), 1.86–1.75 [2H,
m, 5eq-H and CH(CH3)2], 1.70 (1H, dt, J = 14.0, 5.0 Hz, 5ax-H),
1.16 (3H, d, J = 7.0 Hz, 9-H3), 0.97 (3H, d, J = 7.5 Hz, 10-H3), 0.93
[3H, d, J = 7.0 Hz, CH(CH3)2], 0.90 [3H, d, J = 7.0 Hz, CH(CH3)2];
C (100 MHz; CDCl3) 174.67 (CO), 81.61 (6-C), 40.58 (3-C),
33.04 (7-C), 32.66 (5-C), 30.15 (4-C), 17.61 [CH(CH3)2], 17.52
[CH(CH3)2], 14.04 (10-C), 13.67 (9-C); m/z (EI) 170 (M+, 32%),
128 (26), 127 (M+ − iPr, 56%), 100 (27), 99 (63), 56 (100); HRMS
(EI) Found M+, 170.1305; C10H18O2 requires M, 170.1307.
3,4-Dimethyl-6-(prop-2′-yl)tetrahydropyran-2-one 36–38
A solution of diol mixture 30a–32a (0.04 g, 0.25 mmol) was
oxidised using standard TPAP conditions to give the title com-
pounds 36–38 (0.03 g, 64%) as a mixture of diastereoisomers
in a ratio of 84:12:4 (ratio of product peak integrals by GC); Rf
(hexane/ether [1:1]) 0.57; max (thin film) 2965, 2934, 2877, 1742
(CO), 1456, 1373, 1358, 1259, 1237, 1199, 1138, 1097, 1049,
999 cm−1; NMR data for the major isomer 36: H (500 MHz; CDCl3)
4.00 (1H, ddd, J = 11.0, 6.0, 3.0 Hz, 6-H), 2.15 (1H, m, 3-H), 1.86
(1H, m, 5a-H), 1.81 [1H, m, CH(CH3)2], 1.70 (1H, m, 4-H), 1.48
(1H, dt, J = 14.0, 3.5 Hz, 5b-H), 1.21 (3H, d, J = 7.0 Hz, 9-H3),
1.11 (3H, d, J = 6.5 Hz, 10-H3), 0.98 [3H, d, J = 7.0 Hz, CH(CH3)2],
0.93 [3H, d, J = 7.0 Hz, CH(CH3)2]; C (126 MHz; CDCl3) 176.44
(CO), 80.18 (6-C), 40.46 (3-C), 32.81 (5-C), 32.11 [CH(CH3)2],
31.03 (4-C), 21.19 (10-C), 18.01 [CH(CH3)2], 17.85 [CH(CH3)2],
14.20 (9-C); m/z (EI) 170 (M+, 8%), 128 (20), 127 (M+ − iPr, 100%),
99 (83), 83 (33), 81 (73), 71 (34), 70 (52), 69 (50).
1,5-Bisbenzoyloxy-2,3,6-trimethylheptane 30b–32b
To a solution of diol mixture 30a–32a (0.03 g, 0.18 mmol) and
DMAP (0.04 g, 0.34 mmol) in THF (7 ml) was added dropwise a
solution of benzoyl chloride (0.21 ml, 1.84 mmol) and triethylamine
(0.37 ml, 2.68 mmol) in THF (7 ml). The mixture was stirred at RT
for 19 h. Saturated sodium hydrogen carbonate solution (10 ml) and
ether (10 ml) were then added. The aqueous layer was separated
and extracted with ether (3 × 10 ml). The combined organic extracts
were dried over MgSO4, filtered, concentrated and dried in vacuo.
Flash column chromatography (petroleum ether/ethyl acetate [9:1])
gave the title compounds (0.04 g, 60%) as a mixture in a ratio of
82:12:6 (ratio of product peak integrals by GC); Rf (hexane/ethyl
acetate [4:1]) 0.85; data for the major diastereoisomer 30b: max
(thin film) 2963, 2877, 1717 (CO), 1601, 1584, 1491, 1465, 1451,
1388, 1370, 1314, 1275, 1176, 1112, 1069, 1026, 971, 711 cm−1; H
(500 MHz; CDCl3) 8.04 (2H, dd, J = 7.5, 1.0 Hz, Ar–H), 7.93 (2H,
dd, J = 7.5, 1.0 Hz, Ar–H), 7.55 (1H, tt, J = 7.5, 1.0 Hz, Ar–H), 7.49
(1H, tt, J = 7.5, 1.0 Hz, Ar–H), 7.42 (2H, t, J = 7.5 Hz, Ar–H), 7.30
(2H, t, J = 7.5 Hz, Ar–H), 5.17 (1H, dt, J = 9.0, 4.5 Hz, 5-H), 4.18
(1H, d, J = 7.5 Hz, 1-HH), 4.17 (1H, d, J = 6.5 Hz, 1-HH), 2.22 (1H,
m, 2-H), 1.97 (1H, m, 6-H), 1.88 (1H, m, 3-H), 1.74–1.61 (2H, m,
4-H2), 0.99 [3H, d, J = 5.0 Hz, CH(CH3)2], 0.98 [3H, d, J = 5.0 Hz,
CH(CH3)2], 0.91 (3H, d, J = 7.0 Hz, 8-H3), 0.90 (3H, d, J = 7.0 Hz,
9-H3); C (126 MHz; CDCl3) 166.56 (CO), 166.21 (CO), 132.70
(Ar), 132.63 (Ar), 130.58 (ipso-Ar), 130.28 (ipso-Ar), 129.53 (Ar),
129.44(Ar),128.30(Ar),128.19(Ar),76.74(5-C),67.99(1-C),35.72
(4-C), 34.55 (2-C), 31.78 (6-C), 29.80 (3-C), 18.59 [CH(CH3)2],
17.33 [CH(CH3)2], 14.86 (9-C), 10.79 (8-C); m/z (GCMS, CI)
(±)-(3R*,6S*) 3-Methyl-6-prop-2′-yl-tetrahydropyran-2-one
41; and (±)-(3S*,6S*) 3-methyl-6-prop-2′-yl-tetrahydropyran-
2-one 42
Obtained following flash column chromatography as a mixture
in a 66:34 ratio (35%) (GC and NMR); Rf (petroleum ether/ether
[1:1]) 0.45; max (thin film) 2965, 2936, 2877, 1737 and 1731
(CO), 1462, 1377, 1243, 1186, 1119, 1093, 1012, 996, 931 cm−1;
m/z (EI) 156 (M+, 18%), 114 (21), 113 (M+ − iPr, 56%), 84 (80). 41
H (500 MHz; CDCl3) 4.08 (1H, ddd, J = 11.0, 5.5, 3.0 Hz, 6-H),
4.01 2.40 (1H, m, 3-H), 2.02 (1H, m, 4-HH), 1.91–1.81 [3.2H, m,
5-H, CH(CH3)2], 1.68–1.46 (3.2H, m, 5-HH, 4-HH), 1.29 (3H, d,
J = 7.0 Hz, 9-H3), 0.97 [3H, d, J = 7.0 Hz, CH(CH3)2], 0.95 [3H,
d, J = 7.0 Hz, CH(CH3)2]; C (100 MHz; CDCl3) 174.66 (CO),
86.41 (6-C), 36.21 (3-C), 32.92 [CH(CH3)2], 28.44 (4-C), 25.64
(5-C), 17.68 [CH(CH3)2], 17.61 [CH(CH3)2], 17.38 (9-C); 42 H
(500 MHz; CDCl3) 4.01 (1H, ddd, J = 11.5, 6.5, 3.5 Hz, 6-H),
2.59 (1H, m, 3-H), 2.07 (1H, m, 4-HH), 1.91–1.81 [2H, m, 5-HH
and CH(CH3)2], 1.68–1.46 (2H, m, 5-HH and 4-HH), 1.20 (3H, d,
J = 6.5 Hz, 9-H3), 0.99 [3H, d, J = 7.0 Hz, CH(CH3)2], 0.94 [3H, d,
J = 7.0 Hz, CH(CH3)2]; C (100 MHz; CDCl3) 176.65 (CO), 82.70
(6-C), 32.98 (3-C), 32.32 [CH(CH3)2], 25.52 (4-C), 23.41 (5-C),
17.97 [CH(CH3)2], 17.61 [CH(CH3)2], 16.11 (9-C) accompanied
on further elution by (±)-(4S*,6S*) 4-methyl-6-prop-2′-yl-tetra-
hydropyran-2-one 43 (15%); Rf (petroleum ether/ether [1:1]) 0.33;
+
401 (M + NH4 + H+, 60%), 400 (M + NH4 , 100%), 383 (M + H+,
44%), 278 (M+ − PhCO, 51%), 261 (M+ − PhCO2, 90%), 156 (13),
139 (36), 122 (30), 105 (61), 95 (32). Further elution gave 5-hy-
droxy-2,3,6-trimethylheptyl benzoate as a clear oil (0.01 g, 26%);
Rf (hexane/ethyl acetate [4:1]) 0.56; max (thin film) 3493 (broad,
O–H), 2960, 2927, 2876, 1721 (CO), 1602, 1468, 1452, 1383,
1276, 1177, 1115, 1070, 1027, 985 cm−1; H (500 MHz; CDCl3) 8.04
(2H, d, J = 8.0 Hz, Ar–H), 7.55 (1H, m, Ar–H), 7.44 (2H, t, J =
8.0 Hz, Ar–H), 4.25 (1H, dd, J = 11.0, 4.0 Hz, 1-HH), 4.19 (1H, dd,
J = 11.0, 7.0 Hz, 1-HH), 3.49 (1H, dt, J = 9.0, 4.5 Hz, 5-H), 2.11
(1H, m, 2-H), 1.97 (1H, m, 3-H), 1.65 (1H, m, 4-HH), 1.53 (1H, m,
6-H), 1.32 (1H, m, 4-HH), 0.94 [3H, d, J = 7.0 Hz, CH(CH3)2], 0.91
(3H, d, J = 7.0 Hz, 8-H3), 0.91 (3H, d, J = 7.0 Hz, 9-H3), 0.90 [3H,
d, J = 7.0, CH(CH3)2]; C (126 MHz; CDCl3) 166.66 (CO), 132.84
(Ar), 130.42 (ipso-Ar), 129.51 (Ar), 128.34 (Ar), 74.30 (5-C), 68.63
(1-C), 38.89 (4-C), 34.75 (2-C), 33.63 (6-C), 30.30 (3-C), 18.85
[CH(CH3)2], 16.71 [CH(CH3)2], 15.25 (8-C), 10.97 (9-C); m/z (ES+)
579 (M2Na+, 3%), 301 (M + Na+, 100%); HRMS (ES+) Found M+,
279.1963; C17H27O3 requires M, 279.1960.
max (thin film) 2961, 2930, 2875, 1740 (CO), 1464, 1388, 1371,
1282, 1250, 1237, 1183, 1084, 1066, 1002 cm−1; H (500 MHz;
CDCl3) 4.08 (1H, ddd, J = 10.5, 6.5, 4.0 Hz, 6-H), 2.55 (1H, dd,
J = 9.0, 9.0 Hz, 3-HH), 2.18 (2H, m, 3-HH and 4-H), 1.87 [1H, oct,
J = 6.5 Hz, CH(CH3)2], 1.83 (1H, ddd, J = 14.0, 10.5, 7.0 Hz, 5a-H),
1.52 (1H, ddd, J = 14.0, 5.5, 4.0 Hz, 5b-H), 1.10 (3H, d, J = 6.5 Hz,
9-H3), 1.01 [3H, d, J = 6.5 Hz, CH(CH3)2], 0.95 [3H, d, J = 6.5 Hz,
CH(CH3)2]; C (101 MHz; CDCl3) 172.91 (CO), 81.61 (6-C),
37.28 (3-C), 32.43 [CH(CH3)2], 31.94 (5-C), 23.89 (4-C), 21.37
(9-C), 18.07 [CH(CH3)2], 18.02 [CH(CH3)2]; m/z (EI) 156 (M+,
19%), 128 (15), 114 (24), 113 (M+ − iPr, 97%), 85 (100).
(±)-(6S*,3S*,4R*)3,4-Dimethyl-6-(prop-2′-yl)tetrahydropyran-
2-one 35
(±)-(6S*,3S*,5R*) 3,5-Dimethyl-6-prop-2′-yl-tetrahydropyran-
A solution of diol 29a (0.07 g, 0.43 mmol) was oxidised using
standard TPAP conditions to give the title compound 35 (0.05 g,
63%); Rf (hexane/ether [1:1]) 0.73; max (thin film) 2963, 2933,
2870, 1731 (CO), 1457, 1387, 1181, 1133, 1088, 1032, 987 cm−1;
2-one 45 24,25
Obtained following flash column chromatography as a colourless
oil (petroleum ether/ether [1:1]) (45%); Rf (petroleum ether/ether
2 4 0 0
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 2 3 9 3 – 2 4 0 2