N. Ribeiro et al. / Tetrahedron 63 (2007) 3395–3407
3403
(Found: C, 82.59; H, 9.86. C43H60OS requires C, 82.63; H,
9.68%); IR (neat): 3028 (w), 2920 (m), 2846 (m), 1665
(w), 1583 (w), 1453 (m), 1438 (m), 1378 (m), 1364 (m),
1203 (w), 1089 (m), 1066 (m), 1026 (m), 859 (w), 736 (s),
693 (s); 1H NMR (300 MHz, CDCl3): d¼0.73 (1H, s,
CH3), 0.85, 0.88, 0.89 (8H, s, CH3), 1.05–1.24 (4H, m,
2ꢃCH2(13,18)), 1.34, 1.36 (3H, s, CH3), 1.40–1.45 (3H,
m, CH2 and CH), 1.52–1.55 (2H, m, CH2), 1.59 (3H, s,
CH3), 1.64 (6H, s, 2ꢃCH3), 1.74–1.84 (2H, m, CH2),
1.88–1.95 (2H, m, CH2), 2.01–2.11 (5H, m, 2ꢃCH2 and
CH), 2.19 (1H, dd, J 13.5 and 9 Hz, CH2–CHSPh), 2.39
(1H, dd, J 13.5 and 5.7 Hz, CH2–CHSPh), 4.02 (2H, d, J
6.6 Hz, CH2OH), 3.96–4.04 (1H, m, CHSPh), 4.50 (2H, s,
CH2–Ph), 4.96–5.03 (1H, m, CH vinylic), 5.14–5.18 (1H,
m, CH vinylic), 5.24 (0.41H, m, CH vinylic), 5.37–5.42
(1.49H, m, CH vinylic), 7.22–7.42 (10H, m, CH aromatics);
13C NMR (75 MHz, CDCl3): d¼13.6 (CH3), 16.1 (CH3),
16.2 (CH3), 16.6 (CH3), 18.8 (CH2), 21.9 (CH3), 22.1
(CH3), 23.8 (CH2), 24.2 (CH2), 26.4 (CH2), 33.0 (C), 33.2
(CH3), 36.8 (C), 39.1 (CH2), 39.4 (CH2), 41.6 (CH2), 42.3
(CH2), 45.6 (CH2), 45.9 (CH–SPh), 50.1 (CH), 54.6 (CH),
66.6 (CH2OBn), 72.0 (O–CH2–Ph), 119.7 (CH vinylic),
120.8 (CH vinylic), 126.9 (CH vinylic), 127.1 (CH vinylic),
127.2 (CH aromatic), 127.5 (CH aromatic), 127.8 (CH aro-
matic), 128.3 (CH aromatic), 128.5 (CH aromatic), 132.3
(C), 134.0 (CH aromatic), 134.9 (C-Ph), 135.3 (C), 136.7
(C), 138.4 (C-Ph), 140.3 (C); HRMS (MALDI-TOF): calcd
for C43H60OS: 624.436; found [M+Na+]¼647.376; MS
(70 eV, EI): m/z (%): 515 (0.92) (1) [MꢀSPh], 407 (18),
381 (10), 339 (9), 271 (9), 215 (8), 191 (24) [C14H23], 177
(13), 163 (14), 147 (21), 135 (15), 123 (14) [CH2–SPh],
109 (46) [SPh], 91 (100), 81 (46), 69 (26) [isopentenyl],
55 (26) [isobutene].
(75 MHz, CDCl3): d¼13.6 (CH3), 16.1 (CH3), 16.2 (CH3),
16.3 (CH3), 18.9 (CH2), 21.9 (CH3), 22.1 (CH3), 23.8
(CH2), 24.2 (CH2), 26.4 (CH2), 26.7 (CH2), 33.0 (C), 33.2
(CH3), 36.8 (C), 39.1 (CH2), 39.6 (CH2), 39.7 (CH2), 41.9
(CH2), 42.4 (CH2), 50.2 (CH), 55.3 (CH), 59.4 (CH2OH),
122.3 (CH vinylic), 123.3 (CH vinylic), 123.8 (CH vinylic),
124.4 (CH vinylic), 135.4 (C), 135.6 (2ꢃC), 139.9 (C); GC–
MS (70 eV, EI): m/z (%): 205 (23), 204 (100), 191 (4), 189
(15), 161 (21), 148 (9), 135 (11), 121 (14), 109 (24), 95
(15), 81 (24), 69 (14) [isoprenyl], 55 (15).
4.2.13. ((5E,9E)-3-((E)-5-(Benzyloxy)-3-methylpent-3-
enyl)-2,6,10-trimethyl-12-(3,3-dimethyloxiran-2-yl)do-
deca-1,5,9-trienyl)trimethylsilane (19) and ((2E,6E,10E,
14E)-1-(benzyloxy)-3,7,11,15-tetramethyl-17-(3,3-di-
methyloxiran-2-yl)heptadeca-2,6,10,14-tetraen-8-yl)tri-
methylsilane (20). To a stirred solution of sulfide 3 (2 g,
4.71 mmol) in dry THF (30 mL) under an argon atmosphere
at ꢀ78 ꢁC was added dropwise a solution of lithium naph-
thalenide (0.6 M, 17.2 mL, 10.37 mmol) freshly prepared.
After 20 min of reaction at ꢀ78 ꢁC, a solution of chloride
18 (1.33 g, 5.18 mmol) in 3 mL of dry THF was added drop-
wise and the resulting solution was stirred for another hour at
ꢀ78 ꢁC. The reaction was quenched with a saturated solu-
tion of NH4Cl and the mixture was extracted with Et2O.
The organic layer was washed with distilled water and brine,
dried over MgSO4, filtered and concentrated to dryness.
Purification of the resulting yellow oily residue by chro-
matography on silica gel with pentane/Et2O, 9:1, yielded
2.078 g (82%) of the mixture of silanes 19 and 20 with,
respectively, 22% and 78% as a colourless oil: Rf ¼0.31
(pentane/Et2O, 9:1); (Found: C, 78.66; H, 10.79. C35H56O2Si
requires C, 78.30; H, 10.51%); IR (neat): 2956 (m), 2923 (m),
2851 (m), 1666 (w), 1609 (w), 1453 (m), 1377 (m), 1246 (s),
1114 (m), 1086 (m), 1069 (m), 834 (s), 734 (s), 696 (s);
4.2.12. (2E,6E,10E)-13-(1,2,3,4,4a,5,8,8a-Octahydro-
1,1,4a,6-tetramethylnaphthalen-5-yl)-3,7,11-trimethyl-
trideca-2,6,10-trien-1-ol (17). To dry ethylamine (3 mL) at
ꢀ78 ꢁC, lithium wire was added (32 mg, 4.54 mmol) in
small pieces and the solution was coloured in blue. The cou-
pled product 15 (142 mg, 0.23 mmol) in dry THF (1 mL)
was added slowly, the blue colour disappeared and the result-
ing solution was allowed to stir 20 min until the reaction
colour became blue again. Maintaining the temperature at
ꢀ78 ꢁC, sodium benzoate was added until the blue colour
was totally dissipated and the resulting yellow solution
was then quenched with MeOH until colourless. After at-
taining room temperature, water was added until all the
solids dissolved and the volatiles were carefully evaporated
under reduced pressure. The resulting cloudy solution was
extracted four times with ether. The combined organic layer
was washed with water and brine, dried over MgSO4, filtered
and concentrated to dryness. Purification of the resulting yel-
low oily residue by chromatography with pentane/Et2O, 7:3,
yielded 84 mg (75%) of alcohol 17 as colourless oil:
Rf¼0.45 (pentane/Et2O, 7:3); 17a has been isolated by pre-
parative HPLC: (Found: C, 84.03; H, 11.85. C30H50O re-
quires C, 84.44; H, 11.81%); 1H NMR (300 MHz, CDCl3):
d¼0.74 (1.5H, s, CH3), 0.85, 0.86, 0.87, 0.88 (7.5H, s,
CH3), 1.14–1.31 (6H, m, 3ꢃCH2), 1.37–1.50 (3H, m, CH2
and CH), 1.60 (6H, s, 2ꢃCH3), 1.64, 1.68 (6H, s, 2ꢃCH3),
1.82–2.15 (13H, m, 6ꢃCH2 and CH), 4.15 (2H, d, J
6.9 Hz, CH2OH), 5.11 (2H, m, CH vinylic), 5.23 (0.4H, m,
CH vinylic), 5.41 (1.6H, m, CH vinylic); 13C NMR
1
silane 20: H NMR (300 MHz, CDCl3): d¼ꢀ0.02 (9H, s,
Si(CH3)3), 1.25 (3H, s, CH3), 1.29 (3H, s, CH3), 1.43 (1H,
t, J 7.9 Hz, CH–SiMe3), 1.53 (3H, s, CH3), 1.59 (3H, s,
CH3), 1.61 (3H, s, CH3), 1.65 (3H, s, CH3), 1.66–1.76
(2H, m, (CH3)2COCHCH2), 1.94–2.17 (12H, m, 6ꢃCH2
allylics), 2.69 (1H, t, J 6.2 Hz, (CH3)2COCH), 4.03 (2H, d,
J 6.7 Hz, CH2OH), 4.50 (2H, s, O–CH2–Ph), 4.96 (1H, t,
J 6.6 Hz, CH vinylic), 5.09 (1H, t, J 6.6 Hz, CH vinylic),
5.14–5.18 (1H, m, CH vinylic), 5.41 (1H, tq, J 6.8 and
1.3 Hz, CH vinylic), 7.25–7.35 (5H, m, H aromatics); 13C
NMR (75 MHz, CDCl3): d¼ꢀ2.1 (Si(CH3)3), 16.0 (CH3),
16.5 (CH3), 16.8 (CH3), 18.8 (CH3), 24.9 (2ꢃCH3), 26.4
(CH2), 26.8 (2ꢃCH2), 27.5 (CH2), 36.3 (CH2), 39.6 (CH–
SiMe3), 39.7 (CH2), 40.0 (CH2), 58.3 ((CH3)2COCH), 64.2
((CH3)2COCH), 66.6 (CH2OBn), 72.0 (O–CH2–Ph), 120.7
(CH vinylic), 122.7 (CH vinylic), 125.0 (CH vinylic),
125.2 (CH vinylic), 127.5 (CH aromatic), 127.8 (CH aro-
matic), 128.3 (CH aromatic), 133.9 (C), 134.0 (C), 136.1
(C-Ph), 138.6 (C), 140.5 (C); GC–MS (70 eV, EI): m/z
(%): 275 (4), 225 (3), 207 (5), 201 (6), 190 (10), 175 (7),
157 (17), 147 (16), 135 (32), 119 (31), 107 (36) [O–
CH2Ph], 91 (93) [CH2–Ph], 81 (58), 73 (100) [Si(CH3)3],
69 (12) [isopentenyl], 55 (15).
4.2.14. 8-((E)-5-(Benzyloxy)-3-methylpent-3-enyl)-
1,2,3,4,4a,4b,5,8,8a,9,10,10a-dodecahydro-1,1,4a,7,8a-
pentamethylphenanthren-2-ol (21). To a stirred solution of
the mixture of epoxides 19 and 20 (1.9 g, 3.54 mmol) in dry