(C-3), 33.2 (C-2), 25.9 (–OSiC(CH3)3), 18.2 (–OSiC(CH3)3), 9.2
(6-C), −1.3 (–Si(CH3)3), −5.4 (–Si(CH3)2); m/z (EI) 510 (M+,
−1.3 (Si(CH3)3); m/z (ES+) 461 (MNa+); HRMS (ES+): found
MH+, 439.1758, C24H31Si2O4 requires 439.1755.
t
1%), 438 (M+ − Bu − Me, 4), 437 (M+ − TMS, 10), 135 (57), 73
(TMS, 100); HRMS (CI, NH3): found M+, 510.2432, C28H42O3Si3
requires 510.2436.
(1RS,2SR,3RS,4SR)-2-Ethenyl-4-hydroxy-3-hydroxymethyl-6,
7-methylenedioxy-1-(3ꢀ,4ꢀ,5ꢀ-trimethoxyphenyl)-1,2,3,
4-tetrahydronaphthalene 14
(1SR,2SR,3RS)-3-Hydroxymethyl-2-(3ꢀ,4ꢀ-methylenedioxy-
A solution of silacycle 23 (2.0 g, 4.6 mmol) in dichloromethane
(75 ml) was treated with 3,4,5-trimethoxybenzaldehyde dimethy-
lacetal (9.2 mmol) and cooled to 0 ◦C. The solution was then
treated with BF3·Et2O (0.5 M in DCM, 4.6 mmol) and stirred at
0 ◦C for 6 h. The reaction mixture was then poured into aq. NH4Cl
and extracted with dichloromethane (3 × 10 ml). The combined
organic layers were dried over MgSO4, filtered and concentrated.
The crude organic material was dissolved in methanol–THF (5 ml,
1 : 1) and treated with KHCO3 (1.0 mmol) and a 35% w/w solution
of H2O2 (4.0 mmol) at room temperature. The reaction mixture
was then heated under reflux for 5 h and then poured into saturated
aq. Na2S2O3 and extracted with EtOAc (3 × 10 ml). The combined
organic extracts were dried over MgSO4, filtered and concentrated
in vacuo to afford a colourless oil. Flash column chromatography
[pet. ether–ethyl acetate (6 : 4, 4 : 6), ethyl acetate] afforded tetralol
14, which crystallised as a white solid (1.0 g, 53%); Rf: 0.52 (ethyl
acetate); mp 178–182 ◦C (from ethyl acetate); mmax (ATR) 3411–
3318, 2950, 2890, 2850, 1592, 1503, 1485, 1456, 1421, 1331, 1236,
1129, 1022, 930, 879, 796, 668 cm−1; dH (500 MHz, CDCl3) 7.09
(1H, s, 5-H), 6.38 (1H, s, 8-H), 6.15 (2H, s, 2ꢀ-H, 6ꢀ-H), 5.98 (1H,
phenyl)-1-phenyl-1-trimethylsilylsilacyclohex-4-ene 15
To a solution of silacycle 22 (0.2 g, 0.4 mmol) in THF–MeOH
(1 : 1, 2 ml) was added a catalytic amount of p-toluene sulfonic
acid and 0.5 M aq. HCl. The solution was stirred for 1 h at room
temperature then diluted with Et2O and washed with water (5 ml).
The organic layer was dried over MgSO4, filtered, concentrated
and dried in vacuo. Flash chromatography [pet. ether–ether (9 :
1, 4 : 1, 7 : 3)] gave the title compound 15 as a colourless oil
(0.1 g, 64%); Rf 0.3 (pet. ether–ether 7 : 3); mmax (thin film) 3508–
3192 (broad, OH), 3016, 2950, 2882, 1606, 1502, 1484, 1246, 1041,
835 cm−1; dH (500 MHz, CDCl3) 7.29–7.28 (5H, m, Ar-H), 6.72
(1H, d, J 8, Ar-H), 6.65 (1H, s, Ar-H), 6.57 (1H, d, J 8, Ar-
H), 6.15 (1H, m, 5-H), 5.95 (2H, s, –OCH2O–), 5.76 (1H, m,
4-H), 3.55 (1H, dd, J 10, 5, 3-CHHOH), 3.45 (1H, dd, J 10,
5, 3-CHHOH), 2.82 (1H, m, 3-H), 2.63 (1H, d, J 9, 2-H), 1.87
(1H, m, 6-HH), 1.68 (1H, m, 6-HH), −0.02 (9H, s, Si(CH3)3); dC
(126 MHz, CDCl3) 148.0 (Ar-C), 145.2 (Ar-C), 137.9 (ipso-Ar-
C), 134.6 (Ar-C), 134.2 (Ar-C), 131.6 (C-4), 128.9 (Ar-C), 128.1
(Ar-C), 127.9 (C-5), 121.1 (Ar-C), 108.8 (Ar-C), 108.6 (Ar-C),
101.0 (–OCH2O–), 65.6 (3-CH2OH), 45.4 (C-3), 38.8 (C-2), 9.8
(C-6), −0.9 (Si(CH3)3); dSi (100 MHz, CDCl3) −18.96, −22.60;
m/z (ES+) 419 (MNa+); HRMS (ES+): found MNa+, 419.1473,
C22H28O3NaSi2 requires 419.1469.
=
m, 2-CH C), 5.95 (1H, d, J 1.4, –OCHHO–), 5.94 (1H, d, J 1.4,
=
–OCHHO–), 5.07 (1H, bd, J 18.5, C CHH), 5.06 (1H, bd, J
=
7.7, C CHH), 4.99 (1H, m, 4-H), 3.95 (1H, m, CHHOH), 3.88
(2H, m, CHHOH, 1-H), 3.82 (3H, s, 4ꢀ-OCH3), 3.76 (6H, s, 3ꢀ-
OCH3, 5ꢀ-OCH3), 2.94 (1H, d, J 5.8, 4-OH), 2.68 (1H, m, 2-H),
2.42 (1H, m, 3-H), 1.14 (1H, d, J 6.4, –CH2OH); dC (126 MHz,
CDCl3) 153.0 (C-3ꢀ, C-5ꢀ), 147.3 (Ar-C), 146.8 (Ar-C), 140.7 (C-
(1SR,2SR,3RS)-3-Acetoxymethyl-2-(3ꢀ,4ꢀ-methylenedioxy-
phenyl)-1-phenyl-1-trimethylsilylsilacyclohex-4-ene 23
ꢀ
ꢀ
=
1 ), 139.4 (2-CH C), 136.5 (C-4 ), 132.0 (Ar-C), 130.2 (Ar-C),
ꢀ
ꢀ
=
A solution of hydroxysilacycle 15 (100 mg, 0.3 mmol) in
dichloromethane (3 ml) was treated consecutively with diiso-
propylethylamine (DIPEA, 0.18 ml, 1.0 mmol), acetic anhy-
dride (0.05 ml, 0.5 mmol) and a catalytic amount of 4-
(dimethylamino)pyridine (DMAP). The reaction was stirred at
room temperature for 45 min after which time aq. NH4Cl (10 ml)
was added. The aqueous layer was separated and extracted with
dichloromethane (3 × 20 ml). The combined organic layers were
dried over MgSO4, filtered, concentrated and dried in vacuo.
Flash chromatography [pet. ether; pet. ether–ether (9 : 1, 4 :
1)] afforded the title compound 23 as a colourless oil (80 mg,
70%); Rf 0.5 (pet. ether–ether 7 : 3); mmax (thin film) 2955, 2884,
116.3 (C CH2), 109.4 (C-8), 107.7 (C-5), 106.0 (C-2 , C-6 ), 101.0
(–OCH2O–), 70.4 (C-4), 62.0 (3-CH2), 60.8 (4ꢀ-OCH3), 56.1 (3ꢀ-
OCH3, 5ꢀ-OCH3), 49.5 (C-1), 47.02 (C-2), 42.03 (C-3); m/z (ES+)
437 (MNa+); HRMS (ES+): found MNa+, 437.1571, C23H26O7Na
requires 437.1571.
(1SR,2SR,3RS,4SR)-6,7-(Methylenedioxy)-4-(3,4,5-trimethoxy-
phenyl)-1,2,2ꢀ,3,3ꢀ,4-hexahydronaptho[2,2ꢀ-c]furan-1,3ꢀ-diol 27
A solution of tetralol 14 (30 mg, 0.06 mmol) in THF–H2O (1 : 1,
3 ml) was treated with 2,6-lutidine (0.01 ml, 0.1 mmol), osmium
tetroxide (2 mg, 0.006 mmol) and sodium periodate (50 mg,
0.2 mmol) at room temperature. The solution was stirred for 1 h
then poured into H2O and extracted with DCM (3 × 10 ml).
The combined organic layers were dried over MgSO4, filtered,
concentrated and dried in vacuo. Flash column chromatography
(ether) afforded the title compound 27 as a light brown oil (14 mg,
58%) as a mixture of diastereoisomers in the ratio 3 : 1 by NMR;
Rf 0.3 (ether); mmax (thin film) 3155 (broad, OH), 2982, 2901, 1793,
1591, 1482, 1382, 1238, 1130, 913, 731 cm−1; NMR data given for
major isomer: dH (500 MHz, CDCl3) 6.74 (1H, s, Ar-H), 6.48
(2H, s, Ar-H), 6.31 (1H, s, Ar-H), 5.91 (1H, s, –OCHHO–),
5.89 (1H, s, –OCHHO–), 5.19 (1H, m, 2-CHHO), 4.97 (1H,
m, 2-CHHO), 4.70 (1H, s, 3-CHOH), 4.24–4.15 (2H, m, 1-H,
=
1720 (C O), 1502, 1484, 1439, 1285, 1246, 1160, 1041, 896,
835 cm−1; dH (500 MHz, CDCl3) 7.30–7.25 (5H, m, Ar-H), 6.71
(1H, d, J 8, Ar-H), 6.62 (1H, s, Ar-H), 6.55 (1H, d, J 8, Ar-
H), 6.11 (1H, m, 5-H), 5.94 (2H, s, –OCH2O–), 5.71 (1H, m,
4-H), 4.00 (1H, dd, J 10, 5, 3-CHH), 3.81 (1H, dd, J 10,
5, 3-CHH), 2.93 (1H, m, 3-H), 2.48 (1H, d, J 9, 2-H), 1.99
(3H, s, CH3CO), 1.87 (1H, m, 6-HH), 1.69 (1H, m, 6-HH),
=
−0.01 (9H, s, Si(CH3)3); dC (126 MHz, CDCl3) 171.1 (C O),
147.8 (Ar-C), 145.0 (Ar-C), 137.1 (ipso-Ar-C), 136.4 (Ar-C),
134.3 (Ar-C), 133.9 (Ar-C), 130.8 (4-C), 129.8 (Ar-C), 127.8 (Ar-
C), 127.2 (C-5), 120.7 (Ar-C), 108.4 (Ar-C), 100.8 (–OCH2O–),
67.1 (3-CH2), 41.2 (C-3), 34.4 (C-2), 20.9 (CH3CO), 9.5 (C-6),
This journal is
The Royal Society of Chemistry 2007
Org. Biomol. Chem., 2007, 5, 3201–3206 | 3205
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