3044 J . Org. Chem., Vol. 62, No. 10, 1997
Shtarev et al.
and F-3); J (1, 2) ) (3,4) ) -131.8, (1,3) ) (2,4) ) 12.4, (1,4)
32.6, (2,3) -36 Hz.18 1H NMR (300 MHz) δ 7.62 and 7.63 (AB
system, J ) 9 Hz).
H, 6.01; N, 3.34. Found: C, 69.11; H, 6.15; N, 3.31. 19F NMR
(75.4 MHz) ABXY system, δ -143.24 (m, 2F, F-1), -163.86
(m, 1F, F-2), -160.52 (m, 1F, F-3), -143.30 (m, 2F, F-4); J
(1,2) ) -129.2, (1,3) 12.5, (1,4) 29.7, (2,3) -37.7, (2,4) 12.6,
(3,4) -130.8 Hz.18 1H NMR (400 MHz) δ 1.3-2.04 (m, 10H),
3.02 (6H), 4.32 (tt, J ) 8.9, 3.7 Hz, 1H), 6.72 (d, 2H, J ) 9
Hz), 7.15 (d, J ) 9 Hz, 2H), 7.63 (d, J ) 9 Hz, 2H), 7.66 (d, J
) 9 Hz, 2H). Other isomers (E,Z:Z,E ) 4:3) remained in the
mother liquor solution. 6e (E,Z isomer): 19F NMR (75.4 MHz)
δ -141.7 (ddd, 1F, J ) 134, 15, 8 Hz), -159.78 (ddd, 1F, J )
134, 39, 7.5 Hz), -142.05 (ddd, 1F, J ) 39, 21, 15 Hz), -121.65
(ddd, 1F, J ) 21, 8, 7.5 Hz). 6e (Z,E isomer): 19F NMR (75.4
MHz) δ -122.85 (ddd, 1F, J ) 21, 8, 8 Hz), -145.43 (ddd, 1F,
J ) 41, 21, 14 Hz), -156.73 (ddd, 1F, J ) 133, 41, 8 Hz),
-142.1 (ddd, 1F, J ) 133, 14, 8 Hz).
(E,E)- an d (E,Z)-1,4-Bis[4-(cycloh exyloxy)ph en yl]-1,2,3,4-
tetr a flu or o-1,3-bu ta d ien e (4b). Lithium as fresh cut flakes
(0.4 g, 57 mmol) and 20 mL of ether were placed in a flame-
dried flask previously flushed with nitrogen. A solution of
1-bromo-4-(cyclohexyloxy)benzene (1d ) (5.1 g, 20 mmol) in 20
mL of ether was added dropwise for 20 min and then refluxed
for 1.5 h. The flask was cooled to -78 °C, and a precooled
(CO2-ethanol bath) solution of F-1,3-butadiene (1.9 g, 11.7
mmol) in 15 mL of THF was added dropwise for 30 min. The
mixture was stirred for 1.5 h and the cooling bath allowed to
warm to -10 °C. The reaction mixture was worked up as
usual. The crude product contained E,E and E,Z isomers of
4a (86:14%, by 19F NMR). 4b E,E isomer was separated as
yellow crystals, (1.46 g, 31%), mp 133 °C (from hexane). Anal.
Calcd for C28H30F4O2: C, 70.87; H, 6.37. Found: C, 71.15; H,
6.50. MS m/ z 476 (2); 475 (10); 474 (46) M+; 392 (14); 311
(19); 310 (100); 290 (14); 261 (4); 236 (6); 217 (6); 216 (7); 186
(7); 169 (3); 167 (3); 143 (9); 94 (9); 83 (15); 81(12); 71 (10); 69
(7); 57 (12); 55 (59). IR 1634, 1606. 19F NMR (75.4 MHz)
AA′XX′ system, δ -142.67 (m, F-1 and F-4), -161.40 (m, F-2
and F-3); J (1-2) ) (3-4) ) -130.4, (1-3) ) (2-4) 12.2, (1-
4) 30.2, (2-3) -37.3 Hz.18 1H NMR (300 MHz) δ 1.38-2.02
(m, 10H), 4.33 (m, 1H), 6.97 (d, J ) 9 Hz, 2H), 7.69 (d, J ) 9
Hz, 2H). (E,Z)-4b remained in the mother liquor (0.44 g,
yellow oil), being 76% pure, containing 34% of (E,E)-4b. (E,Z)-
4b: 19F NMR (75.4 MHz) δ -141.34 (ddd, J ) 132.7, 13.3, 6.5
Hz), -157.26 (ddd, J ) 132.9, 40.4, 7 Hz), -143.05 (ddd, J )
40.4, 18.5, 13.3 Hz), -121.38 (ddd, J ) 18.5, 7, 6.5 Hz).
(E ,E )-1,4-Bis(4-t olyl)-1,2,3,4-t e t r a flu or o-1,3-b u t a d i-
en e (4c).5 This was prepared following the procedure for
preparation of 4b. 13C{1H}-APT NMR (100.6 MHz) δ 21.43
(CH3), 126.0 (m, quat C), 126.19 (p, J ) 8.7, 4.3 Hz, CH), 129.37
(CH), 139.3 (dm, J ≈ 220 Hz), 140.48 (quat C), 150.1 (dm, J ≈
246 Hz).
Rea ction of E,Z-1-(4-Tolyl)-1,2,3,4,4-p en ta flu or o-1,3-
bu ta d ien e (2b) w ith Bu tyllith iu m . A precooled (-70 °C)
solution of 2b (1.31 g, 5.61 mmol in 20 mL of THF) was added
to butyllithium (60 mL, 0.6 M, 36 mmol, solution in diethyl
ether diluted with 20 mL of ether) at -72 °C for 30 min. The
mixture was stirred at -78 to -72 °C for 1 h and allowed to
warm up to +5 °C, worked up with 5% HCl and NaHCO3
solutions, and extracted with ether. After rotary evaporation
of the solvent, 2.06 g of the residual oil remained. A 1.2 g
amount of it was separated by column chromatography on SiO2
(75 g, 40/100) using pentane-benzene (25:1) as eluent. Frac-
tion I, colorless oil (0.34 g, Rf 0.7) was identified as (E)-1-(4-
tolyl)-1,2,3-trifluoro-4-butylocta-1,3-diene (5c), purity 88%
(overall yield calcd on fractions I and II, 43%). Fraction II,
colorless oil (0.25 g, Rf 0.65) contained 65% of (E,E)-1-(4-tolyl)-
1,2,3,4-tetrafluoroocta-1,3-diene (5a ) (yield 18%), and 35% of
5c (by 19F NMR). Fraction III, colorless oil (42 mg, Rf 0.62)
contained (Z,E)-1-(4-tolyl)-2,3,4-trifluoro-1-butylocta-1,3-diene
(5b), purity 70%, yield 6%.
P r ep a r a t ion of Un sym m et r ica l (E,E,E)-r,ω-Dia r yl-
1,2,3,4,5,6-h exa flu or o-1,3,5-h exa tr ien es (8a-e). The reac-
tion was done in a flame-dried flask flushed with dry nitrogen.
A precooled solution of butyllithium in hexane was added
dropwise using a dropping funnel with jacket (cooling by CO2-
ethanol mixture) to a solution of an equimolar amount of a
para-substituted â-chloro-R,â-difluorostyrene 7a -c (76-80%
of Z isomer, prepared by the reaction of Grignard reagent with
chlorotrifluoroethylene21
) in THF-ether (5:2) mixture at -100
°C and stirred for 1 h. A precooled (CO2-ethanol mixture)
solution of 1-aryl-F-butadiene 2a ,c,d (1.1 equiv) in THF was
added dropwise for 30 min. The mixture was stirred for 1.5
h, and the cooling bath was allowed to warm to -25 °C. The
reaction mixture was worked up with
hydrochloric acid, extracted with ether, and washed with a
and twice with water. The organic
a 5% solution of
5% solution of NaHCO3
layer was dried over MgSO4 and the solvent was rotary
evaporated. The obtained crude product was then purified by
crystallization.
(E ,E ,E )-1-[4-(Cycloh e xyloxy)p h e n yl]-6-(4-t olyl)-1,2,
3,4,5,6-h exa flu or o-1,3,5-h exa tr ien e (8d ). This was pre-
pared from 2d and 7b (yield 25%, from hexane). Anal. Calcd
for C25H22F6O: C, 66.37; H, 4.90. Found: C, 66.37; H, 5.13.
MS m/ z 452 (47) M+; 370 (81); 356 (9); 350 (10); 335 (9); 330
(6); 315 (7); 268 (43); 238 (16); 215 (9); 143 (93); 141 (68); 83
(19); 55 (100). IR 1675, 1637, 1606. 19F NMR (376.5 MHz) δ
-141.49 (ddd, 1F, J ) 127, 31.5, 15.5 Hz), -168.19 (ddd, 1F,
J ) 127, 35, 14.5 Hz), -149.29 (dddd, 1F, J ) 134.5, 35, 31,
14.5 Hz), -150.75 (dddd, 1F, J ) 134.5, 34.5, 31.5, 15 Hz),
-164.96 (ddd, 1F, J ) 129, 34.5, 14.5 Hz), -141.31 (ddd, 1F,
J ) 129, 31, 15 Hz). 1H NMR (300 MHz) δ 1.38-2.0 (m, 10H),
2.43 (3H), 4.33 (m, 1H), 6.97 (d, 2H, J ) 9 Hz), 7.28 (d, J ) 9
Hz, 2H), 7.65 (d, J ) 9 Hz, 2H), 7.68 (d, J ) 9 Hz, 2H). 13C-
{1H}-APT NMR (75 MHz) δ 21.63 (CH3), 23.80 (CH2), 25.70
(CH2), 31.77 (CH2), 75.53 (CH), 115.82 (d, J ) 2 Hz, CH), 120.2
(m, J ) 25, 7 Hz, quat C), 125.5 (m, J ) 25.3, 7.3 Hz, quat C),
126.26 (t, J ) 8.5 Hz; CH), 128.06 (t, J ) 8.9 Hz, CH), 129.35
(d, J ) 2 Hz, CH), 140.92 (quat C), 138-156 (many overlapping
multiplets), 159.57 (quat C).
(E,E)-1-(4-Hydr oxyph en yl)-4-(4-tolyl)-1,2,3,4-tetr aflu or o-
1,3-bu ta d ien e (9). A 67 mg amount of 1-[4-(cyclohexyloxy)-
phenyl]-4-(4-tolyl)-1,2,3,4-tetrafluoro-1,3-butadiene (6d ) was
put in a polyethylene bottle with a magnetic Teflon-covered
stirring bar and cooled in brine bath (-10 °C). Liquid HF (3
mL) was added and stirred for 30 min. Then the flask was
flushed with nitrogen for 20 min, and the rest of acid was
neutralized with a NaHCO3 solution, extracted with diethyl
ether, washed with water, and dried over MgSO4. Ether was
rotary evaporated. The product was purified by TLC on SiO2
eluted with CHCl3 to obtain 9 (28 mg, 53%) Rf 0.2, as a pale
yellow solid, mp 137 °C (purified by sublimation). IR (CHCl3)
3591 (O-H), 1669, 1611. 19F NMR (75.4 MHz) ABXY system,
δ -142.2 (m, 1F), -161.52 (m, 1F), -159.83 (m, 1F), -143.10
(m, 1F). 1H NMR (300 MHz) δ 2.42 (3H), 6.99 (d, J ) 9 Hz,
2H), 7.25 (d, J ) 9 Hz, 2H), 7.37 (d, J ) 9 Hz, 2H), 7.98 (d, J
) 9 Hz, 2H).
Gen er a l P r oced u r e for P r ep a r a tion of Un sym m etr ica l
(E,E)-r,ω-Dia r yl-1,2,3,4-tetr a flu or o-1,3-bu ta d ien es (6a -
i). An excess of lithium (1.5 equiv based on bromo derivative)
in ether was placed in a flame-dried flask previously flushed
with dry nitrogen. A solution of the bromoaromatic 1a -e in
ether was added dropwise at room temperature. When addi-
tion was completed, the mixture was refluxed for 1 h. The
flask was cooled to -78 °C, and a precooled (by CO2-ethanol
mixture) solution of 1-aryl-F-1,3-butadiene 2a -e in THF was
added dropwise during 30-40 min. The mixture was stirred
for 1.5 h and the cooling bath allowed to warm slowly to 0 °C.
The reaction mixture was worked up with a 5% solution of
hydrochloric acid, extracted with ether, and washed with a
5% solution of NaHCO3 and twice with water. Ethereal layer
was dried over MgSO4. The product was purified by crystal-
lization.
P r epar ation of (E,E)-1-(4-Car boxyph en yl)-4-ar yl-1,2,3,4-
tetr a flu or o-1,3-bu ta d ien es (10a ,b). The bromo derivative
(E,E), (E,Z), (Z,E)-1-[4-(N,N-Dim eth yla m in o)p h en yl]-4-
[4-(cycloh exyloxy)p h en yl]-1,2,3,4-tetr a flu or o-1,3-bu ta d i-
en e (6e). This was prepared from 2d and 1e (26% yield, E,E
isomer, from hexane). Anal. Calcd for C24H25F4NO: C, 68.72;
(21) Yagupolskii, L. M.; Kremlev, M. M.; Khranovskii, V. A.; Fialkov,
Yu. A. Zh. Org. Khim. 1976, 12, 1372.