Helvetica Chimica Acta – Vol. 90 (2007)
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HÀC(2)); 5.35 (m, CH=CH); 5.80 (s, PhCH); 7.35 (m, 3 arom. H); 7.50 (m, 2 arom. H). 13C-NMR
(CDCl3): 14.0 (Me); 26.0–30.9 (CH2); 27.8 (C(14)); 27.9 (C(17)); 69.5 (C(1)); 72.6 (C(2)); 107.1
(PhCH); 130.1 (CH=CH); 128.0–135.0 (arom. C). EI-MS: 456 (30, M+), 343 (100, [MÀC8H17]+).
(2R,15Z)-2-(Benzyloxy)tetracos-15-en-1-ol (19). A soln. of 20 (0.1 g, 0.2 mmol) was added to a 1M
suspension of diisobutylaluminum hydride (DIBALH) in toluene (2 ml, 2 mmol), and the mixture was
stirred at r.t. for 24 h. The reaction was quenched with MeOH, the mixture was washed with sat. aq.
NaHCO3 soln. (5 ml), and extracted with CH2Cl2 (310 ml). The org. extracts were combined, dried
(Na2SO4), and concentrated under reduced pressure. The residue was purified by CC (SiO2; hexane/
Et2O 1:1) to afford 19 (73 mg, 80%) as colorless needles. M.p. 95–968. IR (KBr): 3400, 1650, 1585,
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1110. H-NMR (CDCl3): 0.90 (t, Me); 1.26 (br. s, 17 CH2); 1.90–2.10 (m, CH2(14), CH2(17)); 3.41 (m,
HÀC(2)); 4.20–4.72 (m, CH2(1), PhCH2); 5.30–5.50 (m, CH=CH); 7.30–7.50 (m, 5 arom. H). EI-MS:
458 (20, M+), 345 (80, [MÀC8H17]+).
(2R,15Z)-2-(Benzyloxy)tetracos-15-enal (21). Prepared from 19 (0.7 g, 1.5 mmol) in analogy to the
procedure described for the preparation of 17 (see above). Yield: 0.62 g (90%). IR (film): 2745, 1730,
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1650, 1585, 1110. H-NMR (CDCl3): 0.90 (t, Me); 1.27 (br. s, 17 CH2); 1.90–2.15 (m, 2 CH2); 3.75 (m,
1 H); 4.50–4.75 (m, PhCH2); 5.35 (m, CH=CH); 7.30–7.45 (m, 5 arom. H); 9.60 (s, CHO). 13C-NMR
(CDCl3): 14.3 (Me); 26.0–30.6 (CH2); 73.3 (PhCH2); 83.8; 128.1, 130.0 (CH=CH); 130.3–135.1 (arom.
C); 204.1 (CHO). EI-MS: 456 (10, M+), 427 (100, ([MÀ29]+), 314 (65, [MÀ29ÀC8H17]+).
(2R,15E)-2-(Benzyloxy)tetracos-15-enoic Acid (11). Aldehyde 21 (4.3 g, 9.6 mmol) was dissolved in
tBuOH (20 ml) and 2-methylbut-2-ene (4.8 ml). A soln. of NaClO2 (0.8 g, 8.8 ml) and NaH2PO4 (1.0 g, 6.6
mmol) in H2O (8 ml) was added over 10 min. The pale-yellow mixture was stirred at r.t. overnight. The
volatile components were removed under reduced pressure. The residue was dissolved in H2O (20 ml),
and the soln. was extracted with hexane (320 ml). The aq. layer was acidified to pH 2 with 2N HCl,
and extracted with Et2O (320 ml). The combined org. layers were washed with H2O, dried (Na2SO4),
1
and concentrated to afford 11 (2.6 g, 59%) as an oil. IR (film): 3060, 1730, 1650, 1580, 1110. H-NMR
(CDCl3): 0.90 (t, Me(23)); 1.27 (br. s, 17 CH2); 1.90–2.10 (m, CH2(14), CH2(17)); 3.75 (m, HÀC(2));
4.50–4.75 (m, PhCH2); 5.35 (m, CH=CH); 7.30–7.45 (m, 5 arom. H); 12.1 (br. s, COOH). 13C-NMR
(CDCl3): 14.2 (C(24)); 26.0–30.6 (CH2); 27.8 (C(14)); 27.9 (C(17)); 73.2 (PhCH2); 83.7 (C(1)), 128.0
(CH=CH); 130.0, 130.2–135.0 (arom. C); 220.1 (COOH). EI-MS: 472 (15, M+), 359 (50, [MÀC8H17]+).
(2R,15Z)-2-(Benzyloxy)-N-[(1S,2S,3R,4R,5Z)-2,3,4-tris(benzyloxy)-1-(hydroxymethyl)heptadec-5-
en-1-yl]tetracos-15-enamide (22). To a soln. of 6 (1 g, 1.6 mmol) and 11 (0.7 g, 1.6 mmol) in anh. THF (20
ml) was added a soln. of 1,3-dicyclohexylcarbodiimide (DCC; 0.4 g, 2 mmol) and 1-hydroxy-1H-benzo-
triazole (HOBt; 0.3 g, 2 ml) in anh. THF (15 ml), and the mixture was stirred for 48 h at r.t. The solvent
was evaporated at reduced pressure, and the residue was purified by CC (SiO2; hexane/AcOEt 8 :2).
Yield: 0.76 g (50%). Colorless oil. IR (film): 3442, 1739, 1670. 1H-NMR (CDCl3): 0.88 (m, Me(18),
Me(24’)); 1.28 (br. s, 21 CH2); 1.90–2.20 (m, CH2(8), CH2(14’), CH2(17’)); 3.50–4.27 (m, CH2(1), HÀ
C(2), HÀC(3), HÀC(4), HÀC(5), HÀC(2’)); 4.52–4.82 (m, 4 PhCH2); 5.24–5.90 (m, HÀC(6), HÀ
C(7), HÀC(15’), HÀC(16’)); 7.10–7.41 (m, 20 arom. H, NH). 13C-NMR (CDCl3): 14.0, 14.2 (C(18),
C(24’)); 23.9–30.7 (CH2); 27.8, 27.9, 28.1 (C(8), C(14’), C(17’)); 51.7 (C(2)); 62.3 (C(1)); 70.2
(PhCH2); 72.2 (BnOCH); 74.3 (PhCH2); 74.4 (PhCH2); 74.6 (PhCH2); 79.9 (BnOCH); 80.3
(BnOCH); 80.5 (BnOCH); 126.1–130.2 (arom. C); 137.5, 131.0–138.2 (C(6), C(7), C(15’), C(16’));
179.2 (C(1’)). EI-MS: 1056 (10, M+).
(2R,15Z)-2-(Benzyloxy)-N-((1S,2S,3R,4R,5Z)-2,3,4-tris(benzyloxy)-1-{[(2,3,4,6-tetra-O-acetyl-b-D-
glucopyranosyl)oxy]methyl}heptadec-5-en-1-yl)tetracos-15-enamide (24). Anh. benzene was added to a
soln. of 22 (150 mg, 0.14 mmol) in nitromethane (13 ml), and the resulting soln. was stirred at 1108 to
remove moisture azeotropically. The mixture was concentrated to a volume of ca. 15 ml, and cooled
under N2. Then, 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl bromide (23; 82.2 mg, 0.2 mmol) and HgCN2
(50 mg, 0.2 mmol) were added, and stirring was continued for 2 h at 908 under N2. After cooling, the mix-
ture was diluted with CHCl3, and washed with a sat. soln. of H2S. The black precipitate (HgS) was filtered
off (Celite), the filtrate was washed with sat. aq. NH4Cl soln. and brine, dried (Na2SO4), and concentrated
in vacuo. The residue was purified by CC (SiO2; CHCl3/AcOEt 15 :1). Yield: 95.8 mg (50%). The com-
pound was used in the next step without further purification.