1
yellow oil. IR and H NMR spectra matched those quoted in
Typical procedure for the Stille couplings
the literature;13 m/z 338 (Mϩ, 100%), 211 (M Ϫ Iϩ, 50).
A solution of diiodine, tri-n-butyl(4,4-diethoxybut-1-enyl)-
stannane and lithium chloride in THF was degassed at rt.
Pd(PPh3)4 was then added and the mixture was again degassed
before heating at 70 ЊC for 2 days under argon. The reaction
mixture was allowed to cool to rt and was partitioned between
water (5 ml) and dichloromethane (5 ml). The organic layer was
dried (MgSO4), filtered and evaporated.
Preparation of (Z,Z)-4,5-diethyl-3,6-diiodoocta-3,5-diene 4
Tetraethylammonium iodide (2.60 g, 10.12 mmol), iodine
monochloride (450 mg, 2.77 mmol) in dry dichloromethane (30
ml), hex-3-yne (200 mg, 2.44 mmol). Silica gel chromatography
(hexane–ethyl acetate, 98:2 as eluant) afforded the pure
compound (700 mg, 69%) as a yellow oil. δH (300 MHz; CDCl3)
0.96 (6H, t, J 7.5, 2 × CH3), 1.02 (6H, t, J 7.5, 2 × CH3), 2.56
(8H, q, J 7.5, 4 × CH2); m/z (CI) 291.0607 (Mϩ Ϫ I, C12H20I
requires m/z = 291.0610, 100%).
Preparation of 7,7-diethoxy-2-iodohepta-2,4-dienoic acid
methyl ester (Table 2, entry 1). (E)-2,3-Diiodoacrylic acid
methyl ester (135 mg, 0.4 mmol), tri-n-butyl(4,4-diethoxybut-1-
enyl)stannane (172 mg, 0.4 mmol) and lithium chloride (17 mg,
0.4 mmol) in THF (2 ml), Pd(PPh3)4 (18 mg, 15.6 µmol),
T = 70 ЊC, t = 48 h. Silica gel chromatography [petroleum ether
(40–60)–ethyl acetate, 4:1 as eluant] gave the pure product (86
Preparation of (E)-1-(1-ethyl-2-iodobut-1-enyl)-4-methoxy-
benzene 5 and (Z)-3,4-bis(4-methoxyphenyl)hex-3-ene 6
mg, 61%) as a yellow oil. νmax (film)/cmϪ1 3025 (᎐CH), 2950 (CH
3,4-Diiodohex-3-ene (150 mg, 0.45 mmol), p-methoxyphenyl-
boronic acid (70 mg, 0.46 mmol) and sodium bicarbonate (60
mg, 0.57 mmol) were degassed in DMF and water (7 and 1 ml
respectively) for one hour. Pd(PPh3)4 (21 mg, 18.2 µmol) was
then added to the reaction mixture and degassed for a further
30 minutes before heating overnight at 100 ЊC. The reaction
mixture was then allowed to cool down to room temperature,
washed with HCl 10% (20 ml), extracted with diethyl ether
(3 × 15 ml), washed with water (10 ml), dried (MgSO4), filtered
and evaporated. Purification by silica gel chromatography
[petroleum ether (40–60) as eluant] gave the pure products 5 (50
mg, 35%) and 6 (15 mg, 12%), both as yellow oils. 5, δH (300
MHz; CDCl3) 0.96 (3H, t, J 7.5, CH3), 1.11 (3H, t, J 7.5, CH3),
2.04 (2H, q, J 7.5, CH2), 2.33 (2H, q, J 7.5, CH2), 3.86 (3H, s,
OCH3), 6.98 (2H, AB quartet, 9.1 and 146.5, aromatic protons),
7.49 (2H, AB quartet, 9.1 and 146.5, aromatic protons); m/z
(CI) 189.1277 (Mϩ Ϫ I, C13H17O requires m/z = 189.1279, 35%),
᎐
aliphatic), 2860 (CH aliphatic), 1725 (C᎐O), 1600 (C᎐C), 1120
᎐
᎐
(C–O); δH (300 MHz; CDCl3) 1.20 (6H, t, J 7.0, 2 × CH3CH2O),
2.50 [2H, d, J 5.9, (EtO)2CHCH2], 3.45–3.70 (4H, m, 2 × CH3-
CH2O), 3.82 (3H, s, CH3O), 4.53 [1H, t, J 5.9, (EtO)2CH],
6.02 (1H, d, J 15.3, IC᎐CHCH᎐CH), 7.08 (1H, dd, J 11.2
᎐
᎐
and 15.3, IC᎐CHCH᎐CH), 7.37 (1H, d, J 11.2, IC᎐CH); m/z
᎐
᎐
᎐
(CI) 308.9983 (Mϩ Ϫ OEt, C10H14O3I requires m/z = 308.9987,
80%), 182 (Mϩ Ϫ OEtI, 30).
Preparation of 7-hydroxy-2-iodohepta-2,4-dienoic acid methyl
ester (Table 2, entry 2). (E)-2,3-Diiodoacrylic acid methyl ester
(135 mg, 0.40 mmol), tri-n-butyl(4-hydroxybut-1-enyl)stannane
(145 mg, 0.40 mmol) and lithium chloride (17 mg, 0.41 mmol)
in THF (2 ml), Pd(PPh3)4 (18 mg, 15.6 µmol), T = 70 ЊC, t = 40
h. Purification by silica gel chromatography [petroleum ether
(40–60)–ethyl acetate, 4:1 as eluant] gave the product (63 mg,
56%) as a yellow oil. δH (300 MHz; CDCl3) 1.77 (1H, br s, OH,
disappears upon addition of D2O), 2.43 (2H, t, J 6.2, HOCH2-
CH2), 3.74 (2H, t, J 6.2, HOCH2), 3.81 (3H, s, OCH3), 6.05 (1H,
1
107 (C7H7Oϩ, 45); 6, H NMR spectrum matched that quoted
in the literature;10 m/z (FAB) 205 (C6H13, 40%), 107 (C7H7, 90).
Preparation of tri-n-butyl(4-hydroxybut-1-enyl)stannane
dt, J 6.2 and 15.1, IC᎐CHCH᎐CH), 6.10 (1H, dd, J 11.3 and
᎐
᎐
15.1, IC᎐CHCH᎐CH), 7.37 (1H, d, J 11.3, IC᎐CHCH᎐CH);
᎐
᎐
᎐
᎐
But-3-yn-1-ol (0.5 g, 6.9 mmol), tri-n-butyltin hydride (2.4 ml,
9.0 mmol) and AIBN (100 mg, 0.6 mmol) were heated at 80 ЊC
for 7 h under argon. The reaction mixture was allowed to cool
to rt. Silica gel chromatography [petroleum ether (40–60)–ethyl
acetate, 4:1 as eluant] gave the pure product14 (2.1 g, 84%) as
a colourless oil (1H NMR data was identical to that reported in
δC (75.5 MHz; CDCl3) 29.3, 53.1, 61.4, 83.1, 130.5, 141.3, 153.6,
205.7; νmax (film)/cmϪ1 3400 (OH), 3030 (᎐CH), 2960 (CH
᎐
aliphatic), 2865 (CH aliphatic), 1730 (C᎐O), 1600 (C–C); m/z
᎐
ϩ
(CI) 300.0096 (M ϩ NH4 , C8H11IO3 ϩ NH4 requires m/z =
300.0097, 52%); m/z (EI) 282 (Mϩ, 100%), 59 (C2H3O2 , 70).
ϩ
the literature14). νmax(film)/cmϪ1 3320 (OH), 3010 (᎐CH), 2960
᎐
Preparation of 1,1-diethoxynona-6-iodo-3,5-diene (Table 2,
entry 3). (E)-1,2-Diiodopent-1-ene (100 mg, 0.3 mmol), tri-n-
butyl(4,4-diethoxybut-1-enyl)stannane (129 mg, 0.3 mmol) and
lithium chloride (13 mg, 0.3 mmol) in THF (2 ml), Pd(PPh3)4
(14 mg, 12.1 µmol), T = 68 ЊC, t = 48 h. Silica gel chromato-
graphy [petroleum ether (40–60)–ethyl acetate, 4:1 as eluant]
gave the pure product (47 mg, 46%) as a yellow oil. νmax (film)/
(CH aliphatic), 2880 (CH aliphatic), 1590 (C᎐C), 1080 (C–O);
᎐
δC (75.5 MHz; CDCl3) 9.7, 13.8, 27.6, 29.1, 40.9, 61.6, 132.3,
145.0; m/z (EI) 363.1713 (MHϩ, C16H35SnO requires m/z =
363.1709, 10%), 332 (MHϩ Ϫ CH2OH, 5), 306 (Bu3SnCH2 ,
ϩ
70).
Preparation of tri-n-butyl(4,4-diethoxybut-1-enyl)stannane
cmϪ1 3010 (᎐CH), 2980 (CH aliphatic), 2870 (CH aliphatic),
᎐
1600 (C᎐C), 1060 (C–O); δ (300 MHz; CDCl3) 0.90 (3H, t,
4,4-Diethoxybut-1-yne (380 mg, 2.7 mmol), tri-n-butyl-
tin hydride (0.9 ml, 3.5 mmol) and AIBN (50 mg, 0.3 mmol)
were heated at 80 ЊC for 7 h under argon. The reaction
mixture was allowed to cool to rt. Silica gel chromatography
[petroleum ether (40–60)–ethyl acetate, 4:1 as eluant] gave the
pure product (1.1 g, 94%) as a colourless oil. νmax (film)/cmϪ1
᎐
H
J 7.0, CH3CH2CH2), 1.20 (6H, t, J 7.1, 2 × OCH2CH3), 1.25–
1.51 (4H, m, CH3CH2CH2), 2.51 [2H, d, J 5.9, (EtO)2CHCH2],
3.46–3.75 (4H, m, 2 × OCH2), 4.52 [1H, t, J 5.9, (EtO)2CH],
5.95 (1H, d, J 18.8, IC᎐CHCH᎐CH), 5.98 (1H, d, J 6.9, IC᎐
᎐
᎐
᎐
CHCH᎐CH), 6.50 (1H, dd, J 6.9 and 18.8, IC᎐CHCH᎐
᎐
᎐
᎐
CH); m/z (CI) 293.0400 (Mϩ Ϫ OEt, C11H18OI requires m/z =
293.0402, 70%), 166 (Mϩ Ϫ OEtI, 10).
3010 (᎐CH), 2940 (CH aliphatic), 2900 (CH aliphatic), 1590
᎐
(C᎐C), 1050 (C–O); δ (300 MHz; CDCl3) 0.83 (6H, t, J 7.7,
᎐
H
3 × SnCH2), 0.87 (9H, t, J 7.0, 3 × CH3CH2CH2), 1.19 (6H, t,
J 7.0, 2 × CH3CH2O), 1.30 (6H, quintet, J 7.0, 3 × CH2-
CH2Sn), 1.46 [6H, sextet, J 7.0, (CH3CH2CH2CH2)3Sn], 2.47
Preparation of 6-iodo-1-hydroxyundeca-3,5-diene (Table 2,
entry 4). (E)-1,2-Diiodohept-1-ene (140 mg, 0.4 mmol), tri-n-
butyl(4-hydroxybut-1-enyl)stannane (144 mg, 0.4 mmol) and
lithium chloride (17 mg, 0.4 mmol) in THF (3 ml), Pd(PPh3)4
(37 mg, 32.1 µmol), T = 68 ЊC, t = 48 h. Silica gel chromato-
graphy [petroleum ether (40–60)–ethyl acetate, 4:1 as eluant]
gave the pure product (37 mg, 32%) as a yellow oil. νmax (film)/
(2H, t, J 5.6, ᎐CHCH ), 3.45–3.70 (4H, m, 2 × OCH ), 4.52
᎐
2
2
[1H, t, J 5.6, CH(OCH2CH3)2], 5.91 (1H, dt, J 5.6 and 19.0,
HC᎐CHCH ), 6.02 (1H, d, J 19.0, HC᎐CHCH ); δ (75.5 MHz;
᎐
᎐
2
2
C
CDCl3) 9.2, 13.5, 15.5 , 27.2 (CH2), 29.1, 42.3, 60.9, 102.4,
131.0, 143.6; m/z (CI) 435.2289 (MHϩ, C20H43SnO2 requires
m/z = 435.2285, 10%), 389 (C18H37Oϩ, 35), 331 (C16H32ϩ, 55).
cmϪ1 3340 (OH), 3010 (᎐CH), 2980 (CH aliphatic), 2870 (CH
᎐
J. Chem. Soc., Perkin Trans. 1, 2000, 395–400
399