P.P. Onys’ko et al. / Journal of Fluorine Chemistry 130 (2009) 501–504
503
7.97 (2H, d, J 3.9 Hz, 3-H, 30-H). 13C NMR (DMSO-d6)
d
110.61 (C-2),
(Me), 101.34 (C-2), 117.55, 140.45 (C-3, C-4), 128.26 (q, J 300 Hz,
CF3), 151.05 (C-5), 158.60 (q, J 31 Hz, CO). 19F NMR (DMSO-d6):
129.34, 135.70, 138.61. MS m/z (APCI) 292.12 (M-1, 100%). Calc. for
C8H6ClIS2: C, 29.24; H, 1.84; S, 19.52%. Found: C, 29.03; H, 1.96; S,
19.17%.
d
ꢁ73.0. Calc. for C12H10F3IO2S2: I, 29.22; S, 14.77%. Found: I, 29.78;
S, 14.73%.
3b, yield 73%, mp 233–234 8C. 1H NMR (DMSO-d6):
d
2.52 (6H, s,
Bis(5-chloro-2-thienyl)iodonium trifluoroacetate (5c) was
synthesized by the same procedure. Yield 34%, mp 135–136 8C.
Me), 6.79 (2H, d, J 3.5 Hz, 4-H, 40-H), 7.67 (2H, d, J 3.5 Hz, 3-H, 30-H).
MS m/z (APCI) 320.13 (M-1, 100%). Calc. for C10H10ClIS2: C, 33.67;
H, 2.83; S, 17.98%. Found: C, 33.92; H, 2.97; S, 17.74%.
1H NMR (DMSO-d6): 7.25 (2H, d, J 4.2 Hz, 4-H, 40-H), 7.96 (2H, d, J
d
4.2 Hz, 3-H, 30-H). 19F NMR (DMSO-d6):
10H4Cl2F3IO2S2: C, 25.28; H, 0.85; S, 13.50%. Found: C, 24.96; H,
0.83; S, 13.46%.
d
ꢁ73.0. Calc. for
3c, yield 38%, mp 189–190 8C. 1H NMR (DMSO-d6):
d
6.98 (2H, d,
C
J 4.2 Hz, 4-H, 40-H), 7.63 (2H, d, J 4.2 Hz, 3-H, 30-H). MS m/z (APCI)
361 (M-1, 100%). Calc. for C8H4Cl3IS2: C, 24.17; H, 1.01; S, 16.13%.
Found: C, 24.00; H, 0.95; S, 15.85%.
4.2.3. Bis(2-thienyl)iodonium hexafluorophosphate 6a
3d, yield 29%, mp 135–136 8C. 1H NMR (DMSO-d6):
CH3), 4.09 (4H, s, CH2), 6.93 (2H, d, J 3.6 Hz, 4-H, 40-H), 7.73 (2H, d, J
3.6 Hz, 3-H, 40-H). 13C NMR (DMSO-d6):
34.28 (CH2), 52.05 (Me),
d
3.64 (6H, s,
A solution of thiophene 1a (9.45 mL, 0.119 mol) in Ac2O (40 mL)
and TFA (7.5 mL) was added dropwise with vigorous stirring to a
cooled to ꢁ15 8C solution of tris(trifluoroacetoxy)-l3-iodane 2
(0.029 mol) in Ac2O (20 mL). The reaction mixture was left in a
refrigeratorovernight. Thesolventswereevaporatedinvacuum,and
the dark residue was extracted with water (4ꢂ 50 mL) and filtered.
To the resulting filtrate 50% aqueous HPF6 was added dropwise until
precipitation ceased. The solid was filtered, washed with water and
diethyl ether, and dried. Yield 6.3 g (49%), mp 175–176 8C. 1H NMR
d
125.74, 128.63, 137.71, 144.90 (thiophene ring), 170.21 (CO). MS
m/z (APCI) 436.3 (M-1, 100%). Calc. for C14H14ClIO4S2: C, 35.57; H,
2.98; S, 13.57%. Found: C, 35.89; H, 3.11; S, 13.28%.
3e, yield 43%, mp 167–168 8C. 1H NMR (DMSO-d6):
d
4.40 (4H, s,
CH2), 7.04 (2H, d, J 3.9 Hz, 4-H, 40-H), 7.77 (2H, d, J 3.9 Hz, 3-H, 30-
H). 13C NMR (DMSO-d6):
17.52, 117.94, 128.77, 138.16, 138.17,
141.52. MS m/z (APCI) 370.2 (M-1, 100%). Analysis: calc. for
12H8ClIN2S2: C, 35.44; H, 1.98; N, 6.89; S, 15.77%. Found: C, 35.12;
d
(DMSO-d6):
8.19 (2H, d, J 3.9 Hz, 3-H, 30-H). 19F NMR (DMSO-d6):
J = 710 Hz). MS m/z (APCI) 292 (M-1, 100%). Calc. for C8H6F6IPS2: C,
d
7.14 (2H, m, 4-H, 40-H), 7.93 (2H, d, J 5.1 Hz, 5-H, 50-H),
C
d
ꢁ70.3 (d,
H, 1.76; N, 6.95; S, 15.49%.
21.93; H, 1.38; P, 7.07. Found: C, 21.69; H, 1.27; P, 6.92%.
4.2.1. Reaction of 2-iodothiophene 1f with tris(trifluoroacetoxy)-l3
iodane 2
-
Bis(5-methyl-2-thienyl)iodonium hexafluorophosphate 6b. A
saturated aqueous solution of NH4PF6 (2 mL) was added dropwise
to the solution of trifluoroacetate 5b (0.15 g, 0.51 mmol).
Precipitated oily product was separated and triturated with ether
to yield 6b. Yield 0.03 g, 19%, mp 190–192 8C. 1H NMR (DMSO-d6):
A solution of 2-iodothiophene 1f (2.29 g, 10.9 mmol) in Ac2O
(6 mL) and TFA (0.8 mL) was added dropwise with vigorous stirring
to the cooled to ꢁ10 8C solution of tris(trifluoroacetoxy)-l3-iodane
2 (1.28 g, 2.74 mmol) in Ac2O (3 mL). The reaction mixture was left
at room temperature for 48 h and then evaporated in vacuum to
dryness. Water (10 mL) and diethyl ether were added to the black
residue and stirred for 8 h; the solid was filtered and stirred with a
new portion of water (10 mL) and filtered. The saturated aqueous
solution of ammonium chloride was added to the filtrate, and the
precipitated solid was filtered, washed with water and diethyl
ether, and dried at 40 8C in the dark to yield 0.75 g of the mixture
(1:1.06) of 3f and 4. The ratio of 3f:4 was calculated from 1H NMR
spectra and was subsequently confirmed by HPLC-MS data. NMR
d
2.55 (6H, s, Me), 6.86 (2H, d, J 3.6 Hz, 4-H, 40-H), 7.81 (2H, d,
J = 3.6 Hz, 3-H, 30-H). 19F NMR (DMSO-d6):
ꢁ69.6 (d, J = 712 Hz).
31P NMR (DMSO-d6):
ꢁ142.6 (septet, J = 712 Hz). MS m/z (APCI)
d
d
292 (M-1, 100%). Calc. for C10H10F6IPS2: C, 25.76; H, 2.17. Found: C,
25.97; H, 2.35%. Ethereal filtrate, according to 1H NMR spectrum,
contained a mixture (1:0.4) of 2-methyl-5-iodothiophene and 5-
methyl-2-oxo-2,3-dihydrothiophene identified by comparison
with authentic samples.
4.3. 2-Fluorothiophene (1g) and 2-fluorothiophene-based iodonium
salts 7,8
data for 3f: 1H NMR (DMSO-d6):
7.53 (2H, d, J 3.6 Hz, 3-H, 30-H). MS m/z (APCI) 544 (M-1, 100%).
Calculated for C8H4I3S2, M = 544.96. NMR data for 4: 1H NMR
(DMSO-d6): d
7.10 (1H, dd, J 5.1 and 3.6 Hz, 40-H), 7.33 (1H, m, 4-H),
7.50 (1H, d, J 3.6 Hz, 3-H), 7.9 (m, 2H, 30-H, H-50-H). MS m/z (APCI)
418.1 (M-1, 100%). Calculated for C8H5I2S2, M = 419.07.
d
7.32 (2H, d, J 3.6 Hz, 4-H, 40-H),
A mixture of 6a (4.6 g, 10.5 mmol) and dry KF (4 g, 68.9 mol)
was heated at 172–175 8C for 2 h. The volatile products were
distilled at room temperature under reduced pressure (14 mmHg)
into a trap cooled with liquid nitrogen yielding 0.4 g (37%) of 2-
fluorothiophene 1g containing ꢀ20% of 1a. NMR data for 1g: 1H
4.2.2. Bis(2-thienyl)iodonium trifluoroacetate (5a)
NMR (CDCl3):
(CDCl3):
C4H3FS, M = 102.13.
d
6.47 (1H, m), 6.64 (1H, m), 6.69 (1H, m). 19F NMR
ꢁ134.44. MS m/z (APCI) 101 (M-1, 100%). Calc. for
A solution of thiophene 1a (0.08 mol) in Ac2O (35 mL) and TFA
(5 mL) was added dropwise with vigorous stirring to the cooled to
ꢁ15 8C solution of tris(trifluoroacetoxy)-l3-iodane 2 (0.02 mol) in
Ac2O (15 mL). The reaction mixture was left in a refrigerator for
20 h. The solvents were evaporated in vacuum, and water (50 mL)
was added to the black residue and stirred for 24 h. The solid was
filtered and extracted with additional portions of water (4ꢂ
50 mL). The combined aqueous extracts were evaporated in
vacuum and washed with cold water. Yield 3.9 g (49%). 1H NMR
d
A portion of the above obtained mixture (0.35 g) was dissolved
in acetic anhydride (2 mL) and TFA (0.3 mL) and added with
vigorous stirring to
tris(trifluoroacetate)
a
2
cooled to ꢁ10 8C solution of iodine
(0.5 g, 1.1 mmol) in acetic anhydride
(2 mL). The reaction mixture was allowed to stand at room
temperature overnight and evaporated to dryness in vacuum.
Diethyl ether (10 mL) was added to the residue and extracted with
water (3ꢂ 5 mL). The combined aqueous extracts were filtered. A
saturated solution of ammonium chloride was added to the filtrate
until the precipitation ended. The precipitated solid was collected
by filtration, washed with water (3ꢂ 5 mL), and dried in vacuum at
30–40 8C to give 0.15 g of chlorides 7a, 8a and 3a (2:1:0.14),
separated by preparative chromatography as the formates 7b and
(DMSO-d6):
5.1 Hz, 5-H, 50-H), 7.98 (2H, d, J 3.9 Hz, 3-H, 30-H). 19F NMR (DMSO-
d6):
ꢁ73.3. MS m/z (APCI) 292 (M-1, 100%). Calc. for
10H6F3IO2S2: C, 29.57; H, 1.49; S, 15.79%. Found: C, 29.83; H,
d
7.11 (2H, dd, J 5.1 Hz, J 3.9 Hz, 4-H, 40-H), 7.90 (2H, d, J
d
C
1.64; S, 15.32%.
Bis(5-methyl-2-thienyl)iodonium trifluoroacetate (5b) was
synthesized by the same procedure. Yield 17%, mp 91.5–92 8C.
8b. NMR data for 7a: 1H NMR (DMSO-d6):
m). 19F NMR (DMSO-d6):
ꢁ121.57. MS m/z (APCI) 328.2 (M-1,
100%). NMR data for 7b: 1H NMR (DMSO-d6):
6.73 (2H, dd, J 4.5
d 6.81 (2H, m), 7.67 (2H,
1H NMR (DMSO-d6):
d
2.55 (6H, s, Me), 6.86 (2H, d, J 3.5 Hz, 4-H, 40-
d
H), 7.83 (2H, d, J 3.5 Hz, 3-H, 30-H). 13C NMR (DMSO-d6)
d
15.40
d