saturated, aqueous solution of NaHCO3. The organic layer was
washed with a saturated aqueous solution of NaHCO3 and
dried (MgSO4). Evaporation of the solvent under reduced pres-
sure and purification of the residue by flash chromatography on
silica gel (7:3 hexane–EtOAc) afforded the sulfoxide 14 (50 mg,
75%) as a waxy liquid consisting of a 1:28 mixture of ketone
and hydrate, as determined by 19F NMR. Hydrate: νmax (ATR)/
cmϪ1 3334, 3117, 3013, 2964, 1264, 1175; δH(500 MHz) 0.94
(3 H, t, J 7.5, CH3), 2.04 (2 H, m, H-21), 2.56 (2 H, m, H-6),
2.7–2.9 (9 H, m, H-5, 4 × CH2), 3.0–3.2 (3 H, m, H-3, H-5Ј),
(all-Z)-1,1,1-Trifluoro-3-thiaoctadeca-6,9,12,15-tetraen-2-one
20
Reaction of (all-Z)-4-thianonadeca-7,10,13,16-tetraenoic acid
(19)9 with oxalyl chloride, TFAA and pyridine as described for
the preparation of 5 gave the thioester 20 (62%) as an oil. νmax
(film)/cmϪ1 3015, 2966, 1708, 1284, 1206, 1166; δH(200 MHz)
0.96 (3 H, t, J 7.5, CH3), 2.06 (2 H, m, H-17), 2.43 (2 H, m,
H-5), 2.7–2.9 (6 H, m, 3 × CH2), 3.07 (2 H, t, J 7.3, H-4),
5.2–5.5 (8 H, m, 8 × CH᎐); δ (50 MHz) 14.17 (CH ), 20.51,
᎐
C
3
25.49, 25.57, 25.63, 26.34, 29.09 (6 × CH2), 115.54 (q, JCF
289, CF ), 128.62 (2 × CH᎐), 125.85, 126.90, 127.37, 127.63,
5.25–5.45 (9 H, m, 9 × CH᎐), 5.46–5.55 (1 H, m, CH᎐), 5.90
᎐
᎐
᎐
3
(1 H, br s, OH), 6.44 (1 H, br s, OH); δC(126 MHz) 14.23 (CH3),
20.32 (C-6), 20.52 (C-21), 25.49, 25.58, 25.60, 25.61 (4 × CH2),
50.18 (C-3), 52.71 (C-5), 94.09 (q, JCCF 34, C(OH)2CF3), 121.62
(q, JCF 285, CF3), 125.09, 126.96, 127.25, 127.77, 127.82,
131.26, 131.99 (6 × CH᎐), 184.74 (q, J
40, C(O)CF3);
᎐
CCF
δF(188 MHz) Ϫ75.4 (ketone); m/z (EI) 332 (Mϩ, 2%), 276, 79
(100) (HRMS: found: Mϩ 332.1429. C17H23OF3S requires
332.1422).
128.41, 128.59, 128.80, 131.55, 132.04 (10 × CH᎐); δ (188
᎐
F
MHz) Ϫ79.5 (ketone), Ϫ87.5 (hydrate); m/z (EI) 402 (Mϩ, 1%),
385, 299, 79 (100) (HRMS: found: Mϩ 402.1837. C21H29O2F3S
requires 402.1840).
(all-Z)-3-Oxa-2-trifluoromethyl-1,2-epoxyhenicosa-6,9,12,15,
18-pentaene 23
A mixture of the bromoketone 7 (140 µl, 1.3 mmol), the alcohol
12 (250 mg, 1.0 mmol) and Ag2O (334 mg, 1.4 mmol) in dry
CH2Cl2 was stirred at room temperature for 15 h. The product
was isolated by filtration of the reaction mixture through a plug
of silica. Evaporation of solvents under reduced pressure gave
the epoxide 23 (150 mg, 41%) as an oil. νmax (film)/cmϪ1 3014,
2965, 1329, 1195; δH(200 MHz) 0.96 (3 H, t, J 7.5, CH3), 2.06
(2 H, m, H-20), 2.37 (2 H, m, H-5), 2.7–2.9 (8 H, m, 4 × CH2),
3.07 (1 H, d, J 3.7, H-1), 3.1–3.2 (1 H, m, HЈ-1), 3.5–3.8 (2 H,
(5E,9Z,12Z,15Z,18Z)-3-Thiahenicosa-5,9,12,15,18-pentaen-2-
one 16
Reaction
of
(2E,6Z,9Z,12Z,15Z)-octadeca-2,6,9,12,15-
pentaen-1-ol (15)9 with DIAD, triphenylphosphine and thio-
acetic acid as described for the preparation of 13 gave the thio-
acetic ester 16 (84%) as an oil. νmax (film)/cmϪ1 3012, 2964, 1694,
1133; δH(200 MHz) 0.95 (3 H, t, J 7.5, CH3), 2.0–2.2 (6 H, m,
H-7, H-8 and H-20), 2.29 (3 H, s, H-1), 2.7–2.9 (6 H, m,
3 × CH2), 3.46 (2 H, d, J 6.9, H-4), 5.2–5.9 (10 H, m,
m, H-4), 5.2–5.5 (10 H, m, 10 × CH᎐); δ (50 MHz) 14.18
᎐
C
(CH3), 20.50 (C-20), 25.57 (2 × CH2), 25.48, 25.65 (2 × CH2),
27.59 (C-5), 48.88 (q, JCCCF 2, C-1), 65.96 (C-4), 79.92 (q, JCCF
10 × CH᎐); δ (50 MHz) 14.22 (CH ), 20.51, 25.49, 25.58, 25.62,
᎐
C
3
26.78, 31.34, 32.14 (7 × CH2), 30.42 (C(O)CH3), 124.92, 126.98,
40, C-2), 121.26 (q, JCF 278, CF ), 127.80 (2 × CH᎐), 124.58,
᎐
3
127.86, 128.05, 128.20, 128.26, 128.47, 129.10, 131.96, 133.79
126.95, 127.95, 128.26, 128.31, 128.53, 130.69, 131.97 (8 ×
(10 × CH᎐), 195.31 (CO); m/z (EI) 318 (Mϩ, 0.5%), 275, 43
CH᎐); δ (188 MHz) Ϫ78.3 (br s); m/z (EI) 370 (Mϩ, 0.5%), 79
᎐
᎐
F
(100) (HRMS: found: Mϩ Ϫ43, 275.1830. C18H27S requires
(100) (HRMS: found: Mϩ 370.2109. C21H29O2F3 requires
370.2120).
275.1833).
(2E,6Z,9Z,12Z,15Z)-Octadeca-2,6,9,12,15-pentaene-1-thiol 17
(Z)-3-Oxa-2-trifluoromethyl-1,2-epoxynon-6-ene 24
Reduction of the thioester 16 with LAH as described for 8 gave
the thiol 17 (79%) as an oil. νmax (film)/cmϪ1 3012, 2963, 1433;
δH(200 MHz) 0.95 (3 H, t, J 7.5, CH3), 1.38 (1 H, t, J 7.5, SH),
1.9–2.2 (6 H, m, H-4, H-5 and H-17), 2.7–2.9 (6 H, m,
3 × CH2), 3.0–3.2 (2 H, m, H-1), 5.2–5.5 (8 H, m, 4 × Z-
The reaction of (Z)-hex-3-en-1-ol with the bromoketone 7 as
described for 23 gave the epoxide 24 (44%) as an oil. νmax (film)/
cmϪ1 3017, 2967, 1328, 1195; δH(200 MHz) 0.95 (3 H, t, J 7.5,
CH3), 2.03 (2 H, m, H-8), 2.37 (2 H, m, H-5), 3.06 (1 H, d, J 3.7,
H-1), 3.1–3.2 (1 H, m, HЈ-1), 3.5–3.8 (2 H, m, H-4), 5.2–5.5
CH᎐CH), 5.5–5.6 (2 H, m, E-CH᎐CH); δ (50 MHz) 14.23
᎐
᎐
C
(2 H, m, 2 × CH᎐); δ (50 MHz) 14.09 (CH ), 20.58 (CH ), 27.48
᎐
C 3 2
(CH2), 48.87 (q, JCCCF 2, C-1), 66.18 (C-4), 79.98 (q, JCCF 40,
(CH3), 20.52, 25.50, 25.59, 25.65, 26.77, 26.88, 31.98 (7 × CH2),
126.98, 127.86, 128.07, 128.19, 128.26, 128.48, 129.15, 129.51,
C-2), 121.30 (q, JCF 278, CF ), 123.35, 134.62 (2 × CH᎐); δ (188
᎐
3
F
131.26, 131.97 (10 × CH᎐); m/z (EI) 276 (Mϩ, 0.6%), 243, 79
MHz) Ϫ78.8 (br s); m/z (EI) 210 (Mϩ, 4%), 181, 55 (100)
᎐
(100) (HRMS: found: Mϩ 276.1908. C18H28S requires
276.1912).
(HRMS: found: Mϩ 210.0856. C9H13O2F3 requires 210.0868).
1,1,1-Trifluoro-3-phenylthiopropan-2-one 25
(6E,10Z,13Z,16Z,19Z)-1,1,1-Trifluoro-4-thiadocosa-6,10,13,
Sodium hydride (40 mg, 60% dispersion in mineral oil, 1.0
mmol) was washed twice with dry hexane, suspended in dry
ether and cooled in ice before benzenethiol (102 µl, 1.0 mmol)
was added. The mixture was stirred for 30 min at room tem-
perature before addition of the epoxide 23 (200 mg, 0.95
mmol). After 1 h at room temperature the mixture was
quenched with saturated aqueous NH4Cl and the aqueous
phase was extracted with ether. The extract was washed with
brine and dried (MgSO4). Evaporation of ether under reduced
pressure followed by flash chromatography on silica gel (6:4
hexane–EtOAc) gave compound 25 (140 mg, 67%) as an oil
consisting of a 5:3 ratio of ketone and hydrate, as determined
by 19F NMR. νmax (film)/cmϪ1 3451, 3062, 2979, 1749, 1440,
1180; δH(200 MHz) ketone: 3.84 (2 H, s, CH2), 7.1–7.4 (5 H, m,
ArH), hydrate: 3.34 (2 H, s, CH2), 3.96 (2 H, s, OH), 7.1–7.4
(5 H, m, ArH); δC(50 MHz) 39.10 (CC(O)CF3), 39.91 (CC-
(OH)2CF3), 92.47 (q, JCCF 32, C(OH)2CF3), 127.42, 128.35,
129.21, 129.33, 130.29, 131.87 (ArC), 185.06 (q, JCCF 35,
COCF3); δF(188 MHz) Ϫ76.6 (ketone), Ϫ85.6 (hydrate); m/z
16,19-pentaen-2-one 18
Reaction of 17 with bromide 7 as described for 6 gave the
ketone 18 (71%) as a waxy solid, consisting of a 1:2 mixture of
ketone and hydrate as determined by 19F NMR. νmax (film)/cmϪ1
3430, 2990, 2950, 1740, 1180; δH(200 MHz) ketone: 0.96 (3 H, t,
J 7.5, CH3), 1.9–2.2 (6 H, m, H-8, H-9, H-21), 2.7–2.9 (6 H, m,
3 × CH2), 3.07 (2 H, d, J 7.1, H-5), 3.43 (2 H, s, H-3), 5.2–5.8
(10 H, m, 10 × CH᎐), hydrate: 0.96 (3 H, t, J 7.5, CH ), 1.9–2.2
᎐
3
(6 H, m, H-8, H-9, H-21), 2.7–2.9 (8 H, m, 3 × CH2, H-3), 3.24
(2 H, d, J 7.0, H-5), 3.82 (2 H, s, OH), 5.2–5.8 (10 H, m,
10 × CH᎐); δ (50 MHz) mixture of ketone and hydrate: 14.16
᎐
C
(CH3), 20.47, 25.45, 25.53, 25.59, 26.78, 26.83, 32.10, 32.17,
32.69, 33.44, 34.39, 34.84, 92.55 (q, JCCF 32, C(OH)2CF3),
124.02, 124.73, 126.84, 127.78, 127.82, 128.04, 128.10, 128.37,
128.46, 128.96, 128.99, 131.95, 135.16, 135.58, 185.31 (q, JCCF
35, C(O)CF3); δF(188 MHz) Ϫ76.7 (ketone), Ϫ86.0 (hydrate);
m/z (EI) 386 (Mϩ, 2%), 275, 79 (100) (HRMS: found: Mϩ
386.1913. C21H29OF3S requires 386.1891).
J. Chem. Soc., Perkin Trans. 1, 2000, 2271–2276
2275