evaporated. The residue was chromatographed using a gradient of petroleum ether–Et O (7:1ꢆ3:1). Yield of 7, 0.5 ã (80.5%).
2
1
R 0.7 (hexane–Et O, 1:1). Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 3.92 (2Í, t, J = 6.7, Í-1), 3.21 (2Í, m, Í-4),
.15 (2Í, m, Í-7), 0.89 (3Í, t, J = 7, Í-8). C NMR spectrum (75 MHz, CDCl , ꢃ, ppm): 14.88 (s, Ñ-1), 76.58 (s, Ñ-2), 75.34
f
2
3
13
2
3
(
s, Ñ-3), 10.05 (s, Ñ-4), 77.42 (s, Ñ-5), 77.00 (s, Ñ-6), 13.98 (s, Ñ-7,8), .
,5,8-Undecatriynol (8). A suspension of previously dried CuI (0.25 g, 1.30 mmol), NaI (0.19 g, 1.30 mmol), and
K CO (0.13 g, 0.97 mmol) in anhydrous DMF (3 mL) was treated with 7 (0.12 g, 0.65 mmol) and 6 (0.05 g, 0.89 mmol)
2
2
3
dissolved in anhydrous DMF (3 mL). The system was purged with Ar, stirred for 12 h at 20°C, decomposed by saturated
NH Cl solution (150 mL), and extracted with Et O (5 ꢅ 40 mL). The organic layer was dried over Na SO . The solvent was
4
2
2
4
evaporated. The residue was chromatographed using a gradient of Et O–petroleum ether (1:3ꢆ1:1). Yield of 8, 0.08 g (80%),
2
1
R 0.54 (Et O–hexane, 1:1). Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 4.27 (2H, t, J = 6.7, H-1), 3.20 (4H, m, H-4, 7),
.13, 1.32 (2H, m, H-10), 0.88 (3H, t, J = 7, H-11). C NMR spectrum (75 MHz, CDCl , ꢃ, ppm): 51.23 (s, Ñ-1), 77.42 (s, Ñ-2),
f
2
3
13
2
3
7
7.32 (s, Ñ-3), 10.07 (s, Ñ-4, 7), 76.58 (s, Ñ-5, 6), 75.34 (s, Ñ-8, 9), 13.98 (s, Ñ-10), 14.88 (s, Ñ-11).
1
-Bromo-2,5,8-undecatriyne (10). A solution of 8 (0.55 g, 3.43 mmol) in CH Cl (10 mL) was treated with CBr
2 2 4
(
1.18 g, 3.60 mmol) and PPh (0.95 g, 3.60 mmol) dissolved in CH Cl (2 mL) and stirred for 1 h with cooling. The solvent
3 2 2
was evaporated. The residue was chromatographed using a gradient of petroleum ether–Et O (7:1ꢆ3:1). Yield of 10, 0.62 g
2
1
(
81%), R 0.7 (hexane–Et O, 1:1). Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 3.93 (2Í, t, J = 6.7, Í-1), 3.20 (2Í,
f
2
3
1
3
m, Í-4, 7), 1.43 (2H, m, H-10), 0.87 (3Í, t, J = 7, Í-11). C NMR spectrum (75 MHz, CDCl , ꢃ, ppm): 14.78 (s, Ñ-1), 77.42 (s,
3
Ñ-2), 77.38 (s, Ñ-3), 9.8 (s, Ñ-4, 7), 76.32 (s, Ñ-5, 6), 74.82 (s, Ñ-8, 9), 13.87 (s, Ñ-10, 11), .
Methyl 8,11,14,17-Eicosatetraynoate (12). A suspension of previously dried CuI (0.20 g, 1.08 mmol), NaI (0.16 g,
1
8
2
.08 mmol) and K CO (0.11 g, 0.81 mmol) in anhydrous DMF (3 mL) was treated with 10 (0.14 g, 0.81 mmol) and methyl
2 3
-nonynoat (9, 0.08 g, 0.51 mmol) dissolved in anhydrous DMF (3 mL). The system was purged with Ar, stirred for 12 h at
0°C, decomposed by saturated NH Cl solution (150 mL), and extracted with Et O (5 ꢅ 40 mL). The organic layer was dried
4
2
over Na SO . The solvent was evaporated. The residue was chromatographed using a gradient of Et O–petroleum ether
2
4
2
1
(
1:3ꢆ1:1). Yield of 12, 0.12 g (75%). Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 3.67 (3H, s, OCH ), 3.17 (6H, m,
H-10, 13, 16), 2.32 (2Í, t, J = 7, Í-2), 2.16 (4Í, m, Í-7, 19), 1.29–1.70 (8Í, m, Í-3, 4, 5, 6), 0.89 (3Í, t, Í-20). C NMR
3 3
1
3
spectrum (75 MHz, CDCl , ꢃ, ppm): 174.21 (s, C-1), 31.05 (s, C-2), 24.75 (s, C-3), 28.56 (s, C-4), 28.18 (s, C-5, 6), 22.19 (s, C-7),
3
7
4.83 (s, C-8, 9), 9.76 (s, C-10, 13, 16), 74.75 (s, C-11, 12, 14, 15), 76.99 (s, C-17), 76.57 (s, C-18), 13.97 (s, C-19), 18.60 (s,
C-20), 51.47 (s, OCH3).
Methyl 6,9,12,15-Octadecatetraynoate (13). A suspension of previously dried CuI (0.41 g, 2.15 mmol), NaI
0.32 g, 2.15 mmol) and K CO (0.22 g, 1.61 mmol) in anhydrous DMF (3 mL) was treated with 10 (0.24 g, 1.08 mmol) and
(
2
3
methyl 6-heptynoat (11, 0.23 g, 1.61 mmol) dissolved in anhydrous DMF (3 mL). The system was purged with Ar, stirred for
2 h at 20°C, decomposed by saturated NH Cl solution (150 mL), and extracted with Et O (5 ꢅ 40 mL). The organic layer was
1
4
2
dried over Na SO . The solvent was evaporated. The residue was chromatographed using a gradient of Et O–petroleum
2
4
2
1
ether (1:3ꢆ1:1). Yield of 13, 0.23 g (75%). Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 3.68 (3H, s, OCH ), 3.11
3
3
(
6H, m, H-8, 11, 14), 2.35 (2Í, t, J = 7, Í-2), 2.19 (4Í, m, Í-5, 17), 1.63–1.21 (4Í, m, Í-3, 4), 0.90 (3Í, t, J = 6.8, Í-18).
1
3
C NMR spectrum (75 MHz, CDCl , ꢃ, ppm): 173.21 (s, C-1), 28.41 (s, C-2), 24.75 (s, C-4), 22.19 (s, C-5), 76.54 (s, C-6),
3
7
5
4.72 (s, C-7), 10.02 (s, C-8, 11, 14), 74.65 (s, C-9, 10, 12, 13), 79.42 (s, C-15), 77.01 (s, C-16), 13.57 (s, C-17), 13.97 (s, C-18),
1.77 (s, OCH3).
8Z,11Z,14Z,17Z)-Eicosatetraenoic Acid (1). A suspension of P2-Ni [Ni(OAc) , 0.33 g, 1.85 mmol] and NaBH ,
(
2
4
0
.07 g, 1.85 mmol] in EtOH (10 mL) was cooled to 10°C. Methyl ester 12 (0.25 g, 0.81 mmol) in EtOH (5 mL) and
ethylenediamine (0.26 mL, 3.87 mmol) was added to the suspended catalyst in a stream ofAr. The reaction mixture was stirred
for 4 h at 10°C. The amount of H was measured using a gas burette. After H absorption was finished (20 mL), the catalyst
2
2
was filtered off. The filtrate was acidified with H SO (1 M) and extracted with Et O (4 ꢅ 50 mL). The extract was dried over
2
4
2
Na SO and chromatographed using a gradient of Et O–petroleum ether (1:3ꢆ1:1). Yield of pure intermediate, 0.20 mg
2
4
2
(
78%), R 0.56 (Et O–hexane, 1:1).
f 2
An aqueous solution of LiOH (0.3 M, 4 mL) was added in a stream of Ar to a solution of the product (0.20 g,
.63 mmol) in MeOH (3 mL) and stirred for 8 h at room temperature. The MeOH was evaporated. The residue was acidified
0
with aqueous HCl (1 M) to pH 5.0. The products were extracted with Et O (3 ꢅ 50 mL). The extracts were dried over Na SO
2
2
4
and evaporated. The product was purified over a column of silica gel (Et O–hexane, 3:1). Yield of 1, 0.12 ã (62%), R 0.57
2
f
1
(
Et O–hexane, 2:1). Rt 15.048 min. Í NMR spectrum (300 MHz, CDCl , ꢃ, ppm, J/Hz): 5.35–5.48 (8Í, m, H-8, 9, 11, 12, 14,
2
3
1
5, 17, 18), 2.76 (6Í, m, H-10, 13, 16), 2.34 (2Í, t, J = 7, Í-2), 2.09–2.17 (4Í, m, Í-7, 19), 1.27–1.37 (8Í, m, Í-3–6), 0.88
040
1