(2R,3S )-5-Benzyloxy-2,3-epoxy-3-methylpentanal (11)
an orange gum (0.90 g, 29%); [α]3D3 ϩ191.1 (c 0.45, CH2Cl2);
νmax(film)/cmϪ1 [2086, 2014 (FeCO)], 1669 (C᎐O), 1455 (Ph);
᎐
A solution of (COCl)2 (1.93 g, 15.2 mmol, 1.25 eq.) in CH2Cl2
(10 ml) was added to a solution of DMSO (2.37 g, 30.4 mmol,
2.5 eq.) in CH2Cl2 (50 ml) at Ϫ78 ЊC. After 10 min alcohol 7
(2.70 g, 12.1 mmol, 1.0 eq.) was added and followed, after 15
min, by Et3N (4.92 g, 48.6 mmol, 4.0 eq.). The reaction mixture
was poured onto 1 M aq. HCl and the layers separated, the
aqueous layer was extracted with Et2O (200 ml) and the combi-
ned organic fractions washed with brine and dried (MgSO4).
Filtration through a pad of silica and concentration in vacuo
afforded aldehyde 11 as an oil, which was used without further
δH(600 MHz; C6D6) 7.36–7.18 (5 H, m, C6H5CH2O), 5.27
(1 H, m, 5-H), 4.41–4.30 (3 H, m, C6H5CH2O and 9-H), 4.07
(1 H, d, J 8.5, 4-H), 3.88 (1 H, d, J 11.3, 6-H), 3.44 (2 H, m,
1-H × 2), 2.66 (1 H, dd, J 16.9 and 7.5, 8-HA), 2.26 (1 H, dd,
J 16.9 and 3.2, 8-HB), 1.86 (2 H, m, 2-H × 2), 1.29 (3 H, s,
3-CCH3), 1.11 (3 H, d, J 5.9, 10-H × 3), 1.07 (9 H, s,
SiC(CH3)3), 0.23 (3 H, s, Si(CH3) × 1), 0.19 (3 H, s, Si(CH3)
× 1); δC(150 MHz; C6D6) [209.6, 205.4, 200.8, 200.3, 197.6
(Fe(CO) × 4 and 7-C)], 138.5 (Ph ipso), 128.4 (Ph meta × 2),
[128.1–127.6 (Ph ortho × 2 and Ph para)], 91.2 (5-C), 90.0
(4-C), 78.9 (3-C), 73.1 (PhCH2), 66.9 (1-C), 66.0 (6-C), 64.2
(9-C), 52.4 (8-C), 42.8 (2-C), 28.7 (3-CCH3), 25.8 (SiC(CH3)3),
23.7 (10-C), 18.0 (SiC(CH3)3), Ϫ4.8 (Si(CH3) × 2); m/z (ES)
609 (70%, MNaϩ) and 529 (100) [Found (MNaϩ) 609.1580.
C28H38FeNaO8Si requires MNa, 609.1583]; exo iron lactone
complex 13 as an orange gum (1.10 g, 36%); [α]3D3 Ϫ221.2
(c 0.32, CH2Cl2); νmax(film)/cmϪ1 [2087, 2014 (FeCO)], 1669
purification (2.29 g, 86%); νmax(film)/cmϪ1 1720 (C᎐O), 1454
᎐
(Ph); δH(400 MHz; CDCl3) 9.41 (1 H, d, J 4.7, 1-H), 7.30–7.20
(5 H, m, C6H5CH2O), 4.45 (1 H, d, J 12.0, C6H5CHAHBO), 4.41
(1 H, d, J 12.0, C6H5CHAHBO), 3.50 (2 H, t, J 6.1, 5-H × 2),
3.24 (1 H, d, J 4.7, 2-H), 1.95 (1 H, dt, J 14.6 and 6.1,
4-HA), 1.78 (1 H, dt, J 14.6 and 6.1, 4-HB), 1.38 (3 H, s,
3-CCH3); δC(100 MHz; CDCl3) 199.2 (1-C), 138.0 (Ph ipso),
128.4 (Ph meta × 2), 127.7 (Ph para), 127.6 (Ph ortho × 2), 73.1
(PhCH2), 65.8 (5-C), 63.5 (2-C), 62.7 (3-C), 38.3 (4-C), 17.6
(3-CCH3).
(C᎐O), 1455 (Ph); δ (600 MHz; C D ) 7.33–7.18 (5 H, m,
᎐
H
6
6
C6H5CH2O), 5.24 (1 H, m, 5-H), 4.62 (1 H, d, J 8.6, 4-H),
4.46 (1 H, m, 9-H), 4.33 (1 H, d, J 12.0, C6H5CHAHBO), 4.29
(1 H, d, J 12.0, C6H5CHAHBO), 3.94 (1 H, d, J 11.2, 6-H),
3.49 (1 H, m, 1-HA), 3.42 (1 H, m, 1-HB), 2.71 (1 H, dd,
J 15.7 and 7.9, 8-HA), 2.42 (1 H, dd, J 15.7 and 4.4, 8-HB),
2.03 (1 H, quintet, J 7.0, 2-HA), 1.94 (1 H, m, 2-HB), 1.25
(3 H, s, 3-CCH3), 1.10 (3 H, d, J 5.9, 10-H × 3), 1.05 (9 H, s,
SiC(CH3)3), 0.18 (3 H, s, Si(CH3) × 1), 0.15 (3 H, s, Si(CH3)
× 1); δC(150 MHz; C6D6) [209.5, 205.8, 202.2, 200.0, 197.4
(Fe(CO) × 4 and 7-C)], 138.6 (Ph ipso), 128.4 (Ph meta × 2),
[128.1–127.6 (Ph ortho × 2 and Ph para)], 91.2 (4-C), 91.0
(5-C), 79.0 (3-C), 72.9 (PhCH2), 67.1 (6-C), 65.8 (9-C), 65.6
(1-C), 52.2 (8-C), 43.6 (2-C), 26.9 (3-CCH3), 25.8 (SiC(CH3)3),
23.8 (10-C), 17.9 (SiC(CH3)3), Ϫ4.7 (Si(CH3) × 1), Ϫ5.0
(Si(CH3) × 1); m/z (ES) 609 (85%, MNaϩ) and 443 (100)
[Found (MNaϩ) 609.1582. C28H38FeNaO8Si requires MNa,
609.1583].
(5E,2R,7S,8S )-10-Benzyloxy-2-(tert-butyldimethylsilyloxy)-
7,8-epoxy-8-methyldec-5-en-4-one (12)
Phosphonate 8 (4.22 g, 12.0 mmol, 1.2 eq.) was added dropwise
to a suspension of NaH (60% dispersion in mineral oil, 0.44 g,
11.0 mmol, 1.1 eq.) in THF (30 ml) at 0 ЊC followed, after
20 min, by aldehyde 11 (2.20 g, 10.0 mmol, 1.0 eq.) in THF
(10 ml). After 10 min the reaction was poured onto sat. aq.
NH4Cl solution and extracted with Et2O (2 × 100 ml). The
combined organic fractions were washed with brine and dried
(MgSO4). Concentration of the filtrate in vacuo followed by
flash column chromatography (Et2O–petrol = 1 : 3
1 : 1)
afforded alkenone 12 as a pale yellow oil (3.43 g, 82%);
[α]3D0 Ϫ8.0 (c 1.25, CH2Cl2); νmax(film)/cmϪ1 1670 (C᎐O), 1627
᎐
(C᎐C), 1455 (Ph); δ (400 MHz; CDCl ) 7.32–7.22 (5 H, m,
᎐
H
3
C6H5CH2O), 6.61 (1 H, dd, J 15.9 and 6.4, 6-H), 6.31 (1 H, d,
J 15.9, 5-H), 4.45 (2 H, s, C6H5CH2O), 4.28 (1 H, m, 2-H), 3.53
(2 H, t, J 6.2, 10-H × 2), 3.36 (1 H, d, J 6.4, 7-H), 2.74 (1 H, dd,
J 14.9 and 7.1, 3-HA), 2.47 (1 H, dd, J 14.9 and 5.3, 3-HB), 1.97
(1 H, dt, J 14.4 and 6.2, 9-HA), 1.81 (1 H, dt, J 14.4 and 6.2,
9-HB), 1.24 (3 H, s, 8-CCH3), 1.14 (3 H, d, J 6.1, 1-H × 3), 0.79
(9 H, s, SiC(CH3)3), 0.00 (3 H, s, Si(CH3) × 1), Ϫ0.04 (3 H, s,
Si(CH3) × 1); δC(100 MHz; CDCl3) 198.5 (4-C), 141.3 (6-C),
138.5 (Ph ipso), 134.1 (5-C), 128.8 (Ph meta × 2), 128.1 (Ph
para), 128.0 (Ph ortho × 2), 73.5 (PhCH2), 66.7 (10-C), 66.2
(2-C), 63.1 (8-C), 62.0 (7-C), 50.7 (3-C), 38.7 (9-C), 26.2
(SiC(CH3)3), 24.6 (1-C), 18.4 (SiC(CH3)3), 17.5 (8-CCH3),
Ϫ4.2 (Si(CH3) × 1), Ϫ4.5 (Si(CH3) × 1); m/z (ES) 441 (100%,
MNaϩ) [Found (MNaϩ) 441.2433. C24H38NaO4Si requires
MNa, 441.2437].
[(5E,3S,4R,7R,9R)-1-Benzyloxy-9-(tert-butyldimethylsilyloxy)-
3-(carbonyloxy-ꢂC)-7-hydroxy-3-methyl-(4,5,6-ꢃ)-dec-5-en-
4-yl]tricarbonyliron (15)
Al(i-Bu)3 (1 M in PhMe, 2.3 ml, 2.3 mmol, 2.0 eq.) was added
dropwise to a solution of ketone 14 (660 mg, 1.1 mmol, 1.0 eq.)
in CH2Cl2 (6 ml) at 0 ЊC. After 30 min the solution was poured
onto pre-cooled (0 ЊC) 1 M aq. HCl (30 ml) and stirred vigor-
ously for 20 min. CH2Cl2 (20 ml) was added and the layers
separated. The aqueous phase was extracted with Et2O (30 ml)
and the combined organic fractions washed with brine and
dried (MgSO4). Concentration of the filtrate in vacuo followed
by flash column chromatography (Et2O–petrol = 1 : 2
1 : 1)
afforded alcohol 15 as a gum (480 mg, 72%); [α]2D7 ϩ97.7 (c 1.13,
CH2Cl2); νmax(film)/cmϪ1 3423 (OH), [2078, 1999 (FeCO)], 1450
(Ph); δH(600 MHz; C6D6) 7.37–7.21 (5 H, m, C6H5CH2O),
4.70 (1 H, dd, J 12.0 and 8.4, 5-H), 4.39 (1 H, d, J 12.5,
C6H5CHAHBO), 4.37 (1 H, d, J 12.5, C6H5CHAHBO), 4.25 (1 H,
d, J 9.1, 7-H), 4.08 (1 H, d, J 12.0, 6-H), 3.86 (1 H, d, J 8.4,
4-H), 3.82 (1 H, s, OH), 3.80 (1 H, m, 9-H), 3.53 (2 H, m,
1-H × 2), 2.03 (1 H, m, 2-HA), 1.99 (1 H, m, 2-HB), 1.76 (1 H,
dd, J 14.2 and 9.8, 8-HA), 1.53 (1 H, d, J 14.2, 8-HB), 1.35 (3 H,
s, 3-CCH3), 1.02 (3 H, d, J 6.0, 10-H × 3), 0.96 (9 H, s,
SiC(CH3)3), 0.11 (3 H, s, Si(CH3) × 1), 0.06 (3 H, s, Si(CH3) ×
1); δC(150 MHz; C6D6) [211.4, 207.8, 203.8, 200.7 (Fe(CO) ×
4)], 138.8 (Ph ipso), 128.3 (Ph meta × 2), [128.1–127.6 (Ph ortho
× 2 and Ph para)], 87.5 (5-C), 86.4 (4-C), 82.0 (7-C), 78.9 (3-C),
72.9 (PhCH2), 70.3 (6-C), 67.3 (1-C), 65.9 (9-C), 47.9 (8-C),
42.9 (2-C), 28.7 (3-CCH3), 25.6 (SiC(CH3)3), 24.0 (10-C), 17.7
(SiC(CH3)3), Ϫ4.0 (Si(CH3) × 1), Ϫ5.1 (Si(CH3) × 1); m/z (ES)
611 (70%, MNaϩ) and 476 (100) [Found (MNaϩ) 611.1751.
C28H40FeNaO8Si requires MNa, 611.1740].
[(5E,3S,4S,9R)-1-Benzyloxy-9-(tert-butydimethylsilyloxy)-
3-(carbonyloxy-ꢂC)-3-methyl-7-oxo-(4,5,6-ꢃ)-dec-5-en-4-yl]-
tricarbonyliron (13) and [(5E,3S,4R,9R)-1-benzyloxy-
9-(tert-butyldimethylsilyloxy)-3-(carbonyloxy-ꢂC)-3-methyl-
7-oxo-(4,5,6-ꢃ)-dec-5-en-4-yl]tricarbonyliron (14)
Degassed THF (30 ml) was added to diironnonacarbonyl (5.0 g,
13.7 mmol, 2.6 eq.) via cannula and the mixture was stirred
vigorously in the absence of light for 20 min at room temper-
ature. Alkenyl epoxide 12 (2.20 g, 5.3 mmol, 1.0 eq.) was then
added and the reaction mixture was stirred vigorously. After 3 h
the green mixture was filtered through a pad of Celite and
washed with Et2O (60 ml). PhMe (5 ml) was added to the filtrate
and the solution was concentrated in vacuo. Purification of the
residue by flash column chromatography (petrol until all
Fe3(CO)12 had been removed, then Et2O–petrol = 1 : 3
1 : 1)
afforded, in order of elution, endo iron lactone complex 14 as
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 6 6 4 – 1 6 7 5
1669