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N. Chinkov et al.
PRACTICAL SYNTHETIC PROCEDURES
and filtrates were washed with a sat. solution of NH4Cl (until the
blue color vanished), brine and dried over K2CO3. Filtration and
concentration under reduced pressure afforded an orange crude oil,
which was then distilled on Kügelrohr (130 °C/30 mmHg) to yield
Z-2a (6 g, 89%).
1H NMR (200 MHz, CDCl3): d = 0.85 (t, J = 6.97 Hz, 3 H), 1.15–
1.39 (m, 6 H), 1.83 (t, J = 7.43 Hz, 2 H), 2.76 (d, J = 6.58 Hz, 2 H),
3.51 (s, 3 H), 4.91–5.05 (m, 2 H), 5.64–5.81 (m, 1 H), 5.77 (s, 1 H).
13C NMR (50 MHz, CDCl3): d = 14.0, 18.6, 22.5, 28.7, 31.6, 31.9,
34.2, 114.5, 124.0, 125.1, 127.4, 134.6, 137.3.
HRMS (ESI, MeOH): m/z [MH+] calcd for C10H18: 178.1722;
found: 178.1670.
Anal. Calcd for C13H22: C, 87.56; H, 12.44. Found: C, 87.18; H,
12.67.
(1-Benzyl-buta-1,3-diene-2-sulfonyl)-benzene (6a); Typical
Procedure
13C NMR (50 MHz, CDCl3): d = 14.2, 22.8, 28.1, 31.6, 31.7, 32.2,
59.4, 114.1, 118.2, 139.2, 142.5.
A solution of n-BuLi (11.8 mL, 17.7 mmol) in hexanes was added
dropwise to the stirred solution of allylphenyl sulfone (3 g, 16.6
mmol) in THF (20 mL) at –78 °C. After being stirred at –78 °C for
30 min, a solution of benzaldehyde (1.8 g, 16.9 mmol) in THF (5
mL) was added and the mixture was stirred for 1 h at the above tem-
perature. Acetic anhydride (7.5 mL) was then added and the reac-
tion mixture was warmed to r.t. and kept for further 2 h. A solution
of KOH (10 g, 178 mmol) in water (10 mL) was added and stirred
for additional 2 h. The mixture was then diluted with water (50 mL)
and CH2Cl2 (50 mL). After usual work-up and purification on silica
gel (hexane–EtOAc = 9:1), white solid was obtained in 89% yield.
1H NMR (CDCl3, 200 MHz): d = 7.88–7.45 (m, 2 H), 7.57–7.33 (m,
9 H), 6.43–6.28 (dd, J = 18.3, 11.6 Hz, 1 H), 5.88 (d, J = 18.2 Hz, 1
H), 5.44 (d, J = 11.7 Hz, 1 H).
13C NMR (CDCl3, 50 MHz): d = 139.93, 138.60, 138.20, 133.25,
133.08, 130.35, 129.92, 128.88, 128.58, 128.05, 126.40, 123.85.
2-Pentyl-1,3E-pentadiene (4); Typical Procedure
A solution of n-BuLi in hexane (1.7 mL, 2.4 mmol, 2.4 equiv) was
added dropwise to a stirred solution of bis(cyclopentadienyl)zirco-
nium dichloride (350.7 mg, 1.2 mmol, 1.2 equiv) in anhyd THF (10
mL) at –78 °C under inert atmosphere. The temperature was al-
lowed slowly to reach –50 °C and 2a (168 mg, 1 mmol, 1 equiv),
diluted in THF (5 mL) was added dropwise, keeping the tempera-
ture below –50 °C. When the addition was finished, the cooling bath
was removed and the reaction mixture was warmed as fast as possi-
ble to r.t. (the delay in warming the reaction mixture may cause the
formation of side products). It was then heated to 50 °C for 15 min
until that the metalated diene was quantitatively formed (monitored
by GC). The reaction mixture was cooled to r.t. and hydrolyzed with
1 N HCl (20 mL). The layers were separated and the aqueous phase
was extracted four times with Et2O. The combined organic extracts
were washed successively with sat. NaHCO3 solution, brine and
dried over MgSO4. The obtained residue was finally purified by col-
umn chromatography on silica gel with hexane as eluent (110 mg,
80%).
Anal. Calcd for C16H14SO2: C, 71,08; H, 5.22. Found: C, 71.63; H,
5.06.
(1Z)-Buta-1,3-dienylbenzene (8); Typical Procedure
A solution of n-BuLi in hexane (2.12 mL, 1.6 N solution in hexane,
3.4 mmol) was added slowly to a solution of bis(cyclopentadie-
nyl)zirconium dichloride (496.9 mg, 1.7 mmol) in anhyd THF (10
mL) at –78 °C. The solution was stirred for 30 min at –78 °C and
the vinylsulfone 6a (270 mg, 1 mmol) was added at –78 °C. The re-
action mixture was allowed to warm to r.t. very rapidly and stirred
for 2 h. Then, the reaction mixture was quenched by an aq 1 M HCl
solution and diluted with Et2O (10 mL). The layers were separated;
the aqueous layer was extracted with Et2O (3 × 5 mL). The com-
bined organic layers were washed with aq NaHCO3 (3 × 10 mL),
brine (3 × 10 mL) and evaporated under vacuum to afford a crude
residue, which was purified by column chromatography on silica
gel using hexane as eluent to give 8 (95 mg, 73% yield).
IR (CHCl3): 2959 (s), 2932 (s), 2859 (s), 1797 (m), 1717 (m), 1658
(w), 1605 (m), 1456 (s), 1377 (m), 1231 (w) cm–1.
1H NMR (200 MHz, CDCl3): d = 0.87 (m, 3 H), 1.22–1.49 (m, 6 H),
1.73 (d, J = 6.08 Hz, 3 H), 2.15 (t, J = 7.96 Hz, 2 H), 4.80 (s, 1 H),
4.83 (s, 1 H), 5.71 (dq, J = 6.58, 15.72 Hz, 1 H), 6.01 (d, J = 15.77
Hz, 1 H).
13C NMR (50 MHz, CDCl3): d = 13.3, 17.5, 21.9, 27.4, 31.2, 31.6,
111.9, 123.9, 132.8, 145.9.
HRMS (ESI, MeOH): m/z [MH+] calcd for C10H18: 138.1409;
found: 138.1394.
Anal. Calcd for C10H18: C, 86.88; H, 13.12. Found: C, 87.10; H,
13.67.
IR (CHCl3): 1603, 1493, 1005, 948, 905, 665, 764 cm–1.
5-Pentyl-1,4Z,6E-octatriene (5); Typical Procedure
1H NMR (200 MHz, CDCl3, major isomer): d = 7.41–7.17 (m, 5 H),
6.97 (dt, J = 16.8, 11.4 Hz, 1 H), 6.45 (d, J = 11.5 Hz, 1 H), 6.25 (t,
J = 11.4 Hz, 1 H), 5.36 (d, J = 16.7 Hz, 1 H), 5.22 (d, J = 10.1 Hz,
1 H).
13C NMR (50 MHz, CDCl3): d = 137.36, 133.21, 130.79, 130.42,
129.01, 128.22, 127.04, 119.61.
The previously described procedure, as used for the synthesis 4, was
carried out on 2a. When the formation of the dienyl zirconium de-
rivative 3 was complete and confirmed by GC analysis, freshly dis-
tilled allyl chloride (0.12 mL, 1.5 mmol), CuCl (9.9 mg, 0.1 mmol)
and LiCl (85 mg, 2 mmol) were added at 0 °C. The solution was
then heated to 60 °C and stirred at this temperature for 1 h. Quench-
ing the reaction by addition of an aq mixture of NH4Cl–NH4OH (20
mL, 2:1) was performed at r.t. and after filtration through celite, the
layers were separated and the aqueous phase was extracted four
times with Et2O. The combined organic extracts were washed suc-
cessively with sat. NaHCO3 solution, brine and dried over MgSO4.
The crude was purified by column chromatography on silica gel
(hexane) to afford 5 as a unique isomer in 72% yield (128 mg).
HRMS (ES, CH2Cl2): m/z [M] calcd for C10H10: 130.0772; found:
130.0783.
Anal. Calcd for C10H10: C, 92.25; H, 7.75. Found: C, 91.89; H, 7.42.
E-(2-Vinyl-penta-1,4-dienyl)-benzene (9); Typical Procedure
A solution of n-BuLi in hexane (2.12 mL, 1.6 N solution in hexane,
3.4 mmol) was added slowly to a solution of bis(cyclopentadie-
nyl)zirconium dichloride (496.9 mg, 1.7 mmol) in anhyd THF (10
mL) at –78 °C. The solution was stirred for 30 min at –78 °C and
the vinylsulfone 6a (270 mg, 1 mmol) was added at –78 °C. The re-
action mixture was allowed to warm to r.t. very rapidly and stirred
for 2 h. Anhydrous CuCl (1.8 mmol) and LiCl (3.6 mmol) were add-
ed to the reaction mixture and heated at 50 °C for 1 h. When the
transmetalation step was over and 7Cu was formed as described
IR (CHCl3): 3080 (m), 3007 (m), 3038 (m), 3007 (s), 2959 (s), 2859
(s), 1638 (m), 1451 (s), 1378 (m), 1120 (m) cm–1.
1H NMR (200 MHz, CDCl3): d = 0.87 (t, J = 6.78 Hz, 3 H), 1.24–
1.52 (m, 6 H), 1.76 (d, J = 6.744 Hz, 3 H), 2.14 (t, J = 7.92 Hz, 2 H),
2.88 (t, J = 6.83 Hz, 2 H), 4.93–5.05 (m, 2 H), 5.21 (t, J = 7.5 Hz, 1
H), 5.62–5.84 (m, 2 H), 6.24 (d, J = 15.7 Hz, 1 H).
Synthesis 2004, No. 14, 2411–2417 © Thieme Stuttgart · New York