10.1002/ejoc.201601367
European Journal of Organic Chemistry
FULL PAPER
transferred to a flask containing 1-acetylthio-4-iodobenzene (5) (275 mg,
0.99 mmol), Pd(OAc)2 (14 mg, 62 µmol), CuI (4.5 mg, 24 µmol), dppf (17
mg, 31 µmol) and triphenylphosphine (27.5 mg, 105 µmol). An argon
flushed solution of THF (25 mL) and diisopropylethylamine (1 mL, 5.7
mmol) was added via cannula and the reaction was subjected to
ultrasonication for 18 hours at 40 °C. The crude reaction mixture was
partitioned between sat. aqueous NH4Cl (100 mL) and CH2Cl2 (100 mL).
The phases were separated and the organic phase was washed with
brine, dried over MgSO4, filtered and concentrated in vacuo. The residue
was purified by flash column chromatography (1% EtOAc in toluene) to
yield 6 as a red solid (103 mg, 51%). TLC (1% EtOAc in toluene): Rf =
(E)-S,S',S'',S'''-(((((Ethene-1,2-diylbis(5-((4,5-bis(butylthio)-1,3-dithiol-
2-ylidene)methyl)benzene-2,1,4-triyl))tetrakis(ethyne-2,1-
diyl))tetrakis(benzene-4,1-diyl))tetrakis(ethyne-2,1-
diyl))tetrakis(benzene-4,1-diyl)) tetraundecanethioate (11): To an
argon purged flask containing 4 (42 mg, 49 µmol), 10 (130 mg, 258 µmol),
PdCl2(PPh3)2 (12 mg, 17 µmol) and CuI (3 mg, 16 µmol) was added an
argon flushed solution of triethylamine (40 mL) and THF (40 mL) via
cannula, and the resulting solution was subjected to ultrasonication at
35 °C for 24 hours. The mixture was concentrated in vacuo and the crude
residue was purified by flash column chromatography (20% CH2Cl2 in
CS2) to afford 11 as a red solid (22 mg, 19%). TLC (25% CH2Cl2 in CS2):
Rf = 0.52. Mp >250 °C. 1H NMR (500 MHz, CDCl3): δ 7.84 (s, 2H), 7.72
(s, 2H), 7.56 (d, J = 8.3 Hz, 4H), 7.51 (d, J = 8.3 Hz, 4H), 7.49 (d, J = 8.3
Hz, 4H), 7.46 (d, J = 8.3 Hz, 4H), 7.45 (d, J = 8.3 Hz, 4H), 7.41 (d, J = 8.3
Hz, 4H), 7.40 (s, 2H), 7.33 (d, J = 8.3 Hz, 4H), 7.21 (d, J = 8.3 Hz, 4H),
6.99 (s, 2H), 2.93 – 2.87 (m, 8H), 2.70 – 2.62 (m, 8H), 1.78 – 1.65 (m,
16H), 1.54 – 1.44 (m, 8H), 1.42 – 1.24 (m, 56H), 0.97 (t, J = 7.4 Hz, 6H),
0.95 (t, J = 7.3 Hz, 6H), 0.89 (t, J = 6.9 Hz, 12H) ppm. 13C NMR (126
MHz, CDCl3): δ 196.85, 196.78, 136.48, 136.43, 135.53, 134.34, 134.33,
132.35, 132.28, 131.95, 131.92, 131.74, 131.70, 129.05, 128.85, 128.52,
128.45, 127.65, 125.00, 124.08, 124.02, 123.29, 123.21, 123.20, 123.18,
122.54, 121.31, 111.39, 96.17, 95.69, 91.12, 90.98, 90.87, 90.80, 90.26,
90.20, 44.06, 44.00, 36.30, 36.01, 32.08, 32.06, 32.03, 31.92, 29.77,
29.74, 29.67, 29.63, 29.50, 29.49, 29.48, 29.47, 29.24, 29.21, 25.77,
25.71, 22.85, 22.85, 21.92, 21.90, 14.28, 13.84, 13.81 ppm (2 masked
peaks). HR-MS (MALDI+, FT-ICR, dithranol): m/z 2361.8940 [M+ •], calcd
for (C146H160O4S12+●): m/z 2361.8993.
1
0.26. Mp 162 – 165 °C. H NMR (500 MHz, CDCl3): δ 7.92 (s, 2H), 7.75
(s, 2H), 7.62 (d, J = 8.4 Hz, 4H), 7.56 (d, J = 8.4 Hz, 4H), 7.53 (s, 2H),
7.43 (d, J = 8.4 Hz, 4H), 7.35 (d, J = 8.4 Hz, 4H), 6.98 (s, 2H), 2.95 –
2.79 (m, 8H), 2.46 (s, 6H), 2.43 (s, 6H), 1.74 – 1.60 (m, 8H), 1.51 – 1.41
(m, 8H), 0.95 (t, J = 7.4 Hz, 6H), 0.93 (t, J = 7.4 Hz, 6H) ppm. 13C NMR
(126 MHz, CDCl3): δ 193.42, 193.37, 136.89, 136.75, 135.73, 134.48,
134.44, 132.34, 132.33, 129.39, 128.95, 128.95, 128.70, 128.65, 127.44,
124.84, 124.33, 122.44, 121.33, 111.09, 95.56, 95.27, 89.74, 89.53,
36.24, 35.97, 32.00, 31.87, 30.48, 30.44, 21.86, 21.84, 13.79, 13.77 ppm
(1 masked peak). Anal. Calcd. for C78H72O4S12: C, 64.25; H, 4.98. Found:
C, 64.13; H, 5.17. HR-MS (MALDI+, FT-ICR, dithranol): m/z 1456.2077
[M+●], calcd for (C78H72O4S12+●): m/z 1456.2074.
tert-Butyl(4-((4-iodophenyl)ethynyl)phenyl)sulfane (9): To an argon
flushed solution of tert-butyl(4-ethynylphenyl)sulfane (7) (1.41 g, 7.41
mmol), 1,4-diiodobenzene (8) (7.52 g, 22.8 mmol) in THF (30 mL) and
triethylamine (30 mL) was added PdCl2(PPh3)2 (385 mg, 0.55 mmol) and
CuI (147 mg, 0.77 mmol). The reaction mixture was left stirring 14 hours
at ambient temperature, after which time the reaction mixture was
partitioned between sat. aqueous NH4Cl (100 mL) and CH2Cl2 (100 mL).
The phases were separated and the organic phase was washed with
brine, dried over MgSO4, filtered and concentrated in vacuo. The residue
was purified by flash column chromatography (0-5% CH2Cl2 in heptane)
to furnish 9 as a white solid (2.11 g, 73%). TLC (heptanes): Rf = 0.22. Mp
Ethyl 3-([4-iodophenyl]thio)propanoate (13): Triphenylphosphine (18.0
g, 68.6 mmol) was slowly added to
a stirring solution of 4-
iodobenzenesulfonyl chloride (7.02 g, 23.21 mmol) in argon flushed
anhydrous acetonitrile (125 mL) under argon. The reaction mixture was
heated to 60 °C for 20 min, whereafter water (0.82 mL, 45.5 mmol) was
added, followed by addition of potassium carbonate (9.3 g, 67.3 mmol).
Ethyl 3-bromopropionate (4.6 mL, 35.9 mmol) was added and the
contents of the vessel were heated to reflux point for 20 hours. The
reaction mixture was poured into Et2O and passed through a short plug
of silica and subsequently purified using flash column chromatography
(50% CH2Cl2 in heptanes) to yield 13 as an off-white solid (7.67 g, 98%).
Mp 39.0 – 40.3 °C. 1H NMR (500 MHz, CDCl3): δ 7.60 (d, J = 8.4 Hz, 2H),
7.09 (d, J = 8.4 Hz, 2H), 4.14 (q, J = 7.2 Hz, 2H), 3.15 (t, J = 7.4 Hz, 2H),
2.60 (t, J = 7.4 Hz, 2H), 1.25 (t, J = 7.2 Hz, 3H) ppm. 13C NMR (126 MHz,
CDCl3): δ 171.66, 138.11, 135.64, 131.65, 91.52, 60.96, 34.39, 28.98,
14.33 ppm. Anal. Calcd. for C11H13IO2S: C, 39.30; H, 3.90. Found: C,
39.33; H, 3.52. GC-MS (EI): m/z 336 [M+●].
1
87 – 89 °C. H NMR (500 MHz, CDCl3): δ 7.70 (d, J = 8.5 Hz, 2H), 7.51
(d, J = 8.4 Hz, 2H), 7.47 (d, J = 8.4 Hz, 2H), 7.25 (d, J = 8.5 Hz, 2H), 1.30
(s, 9H) ppm. 13C NMR (126 MHz, CDCl3): δ 137.72, 137.40, 133.77,
133.24, 131.62, 123.41, 122.73, 94.50, 90.39, 90.05, 46.69, 31.14 ppm.
Anal. Calcd. for C18H17IS: C, 55.11; H, 4.37. Found: C, 55.22; H, 4.28.
GC-MS (EI): m/z 392 [M+●].
S-(4-((4-Iodophenyl)ethynyl)phenyl) undecanethioate (10): To
a
stirring solution of 9 (300 mg, 0.76 mmol) and undecanoyl chloride (1.2
mL, 5.4 mmol) in a mixture of MeCN (16 mL) and toluene (4 mL) was
added bismuth(III) trifluoromethanesulfonate (180 mg, 0.27 mmol), and
stirring was continued for 3 hours at ambient temperature. The reaction
mixture was added to cold sat. aqueous NaHCO3 (20 mL) and extracted
with CH2Cl2 (20 mL). The organic phase was filtered through cotton wool,
then concentrated in vacuo, and the resulting oil was purified by flash
column chromatography (20% CH2Cl2 in heptanes) to yield 10 as a white
solid (153 mg, 40%). TLC (20% CH2Cl2 in heptanes): Rf = 0.19. Mp 114 –
116 °C. 1H NMR (500 MHz, CDCl3): δ 7.70 (d, J = 8.5 Hz, 2H), 7.53 (d, J
= 8.6 Hz, 2H), 7.39 (d, J = 8.6 Hz, 2H), ca. 7.25 (“doublet” – overlapping
with the CHCl3 signal, “2H”), 2.69 – 2.63 (m, 2H), 1.75 – 1.68 (m, 2H),
1.39 – 1.23 (m, 14H), 0.88 (t, J = 7.0 Hz, 3H) ppm (one signal obscured
by the solvent). 13C NMR (126 MHz, CDCl3): δ 197.09, 137.73, 134.40,
133.29, 132.23, 128.66, 124.10, 122.63, 94.60, 90.23, 90.11, 44.03,
32.04, 29.69, 29.56, 29.44, 29.39, 29.11, 25.73, 22.83, 14.27. ppm. Anal.
Calcd. for C25H29IOS: C, 59.52; H, 5.79. Found: C, 59.45; H, 5.70. HR-
MS (ESI+, FT-ICR, MeOH + 0.1% TFA): m/z 505.1067 [M+H+], calcd for
(C25H30IOS+): m/z 505.1057.
Diethyl
3,3'-((((2,5-diformyl-1,4-phenylene)bis(ethyne-2,1-
diyl))bis(4,1-phenylene))bis(sulfanediyl))dipropionate (14): To
a
solution of 12 (1.01 g, 3.08 mmol) in a mixture of THF (35 mL) and
MeOH (80 mL) was added potassium carbonate (2.11 g, 15.2 mmol) and
the contents of the vessel were stirred for 10 min, whereafter the mixture
was poured into Et2O (300 mL), washed with water (3 x 300 mL) followed
by brine (300 mL). The organic phase was dried over MgSO4, filtered and
concentrated in vacuo. The white residue was transferred to a flask with
CuI (59 mg, 0.31 mmol), Pd(OAc)2 (139 mg, 0.62 mmol),
triphenylphosphine (324 mg, 1.24 mmol), dppf (342 mg, 0.62 mmol) and
ethyl 3-([4-iodophenyl]thio)propanoate (13) (3.62 g, 10.8 mmol) and
placed under an atmosphere of argon. Argon flushed toluene (50 mL)
and triethylamine (5 mL, 35.9 mmol) were added via cannula and the
reaction mixture was left stirring for 15 hours at ambient temperature.
The crude reaction mixture was partitioned between sat. aqueous NH4Cl
(200 mL) and CH2Cl2 (200 mL) and the phases separated. The organic
phase was washed with brine (200 mL), dried over MgSO4, filtered and
concentrated in vacuo. The residue was purified by flash column
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