A general and convenient preparation of [Bis(trifluoroacetoxy)iodo] perfluoroalkanes and [Bis(trifluoroacetoxy)iodo] arenes by oxidation of organic iodides using Oxone and trifluoroacetic acid

Article abstract of DOI:10.1021/jo902733f

"Chemical Equation Presented" [Bis(trifiuoroacetoxy)iodo] perfiuoroalkanes C_nF_2n+1I(OC-OCF₃)₂ (n = 4, 6, 8, 10, 12) can be conveniently prepared by the oxidation of the corresponding perfluoroalkyl iodides with Oxone in trifluoroacetic acid at room temperature and subsequently converted to the stable [hydroxy(tosyloxy)-iodo] perfluoroalkanes, C_nF_2n+1I(OH)OTs, by treatment with p-toluenesulfonic acid. This general and convenient procedure has been further extended to the synthesis of various [bis(trifluoroacetoxy)iodo]arenes, ArI(OCOCF₃)₂.

Full text of DOI:10.1021/jo902733f

pubs.acs.org/joc
synthesis.1 In a series of recent publications,2 it has been
A General and Convenient Preparation of
[Bis(trifluoroacetoxy)iodo]perfluoroalkanes and
[Bis(trifluoroacetoxy)iodo]arenes by Oxidation of
Organic Iodides Using Oxone and Trifluoroacetic Acid
demonstrated that [bis(trifluoroacetoxy)iodo]perfluoroalkanes
as well as other fluorous iodine(III) derivatives3 are particularly
useful recyclable oxidizing reagents that can be easily recovered
from the reaction mixture using fluorous techniques. The most
common synthetic approach to the fluorous bis(trifluoroacetoxy)
iodides involves the oxidation of appropriate perfluoroalkyl
iodides with 80% hydrogen peroxide and trifluoroacetic anhy-
dride,2,4 which is a potentially hazardous and inconvenient
procedure. Herein we report a straightforward experimental
protocol for preparation of [bis(trifluoroacetoxy)iodo]per-
fluoroalkanes 2 by the oxidation of corresponding perfluoro-
alkyl iodides 1 with Oxone (2KHSO5 KHSO4 K2SO4) in
trifluoroacetic acid at room temperature. The relatively un-
stable and hygroscopic trifluoroacetates 2 can be subsequently
converted to the stable [hydroxy(tosyloxy)iodo]perfluoro-
alkanes 3 in almost quantitative yields by treatment with
p-toluenesulfonic acid (Scheme 1).
Aleksandra A. Zagulyaeva, Mekhman S. Yusubov,† and
Viktor V. Zhdankin*
University of Minnesota, Duluth, Minnesota 55812.
The Siberian State Medical University and The Tomsk
†
Polytechnic University, 2 Moskovsky trakt,
634050 Tomsk, Russia.
3
3
vzhdanki@d.umn.edu
Received January 11, 2010
The yields and melting points of the fluorous iodine(III)
products 2 and 3 are summarized in Table 1. Trifluoroace-
tates 2 were separated from inorganic salts by extraction with
acetonitrile (for 2a-c) or acetone (for 2d,e) after evaporation
of the reaction mixture. Crude products 2 were converted to
tosylates 3 by treatment with TsOH H2O in acetonitrile or
3
acetone. Analytically pure tosylates 3 were obtained by
recrystallization from acetonitrile. All previously reported
products were identified by comparison of their NMR spectra
and mp with literature data;4b new products 3d,ewere identified
by 1H, 19F, and 13C NMR spectra and elemental analysis. The
fluorous tosylates 3 are generally stable for storage at room
temperature and, in contrast to the trifluoroacetates 2, are not
sensitive to light and moisture.
In the next step, we investigated the applicability of this
convenient procedure to the synthesis of various [bis(trifluoro-
acetoxy)iodo]arenes, ArI(OCOCF3)2. The most general known
synthetic approaches to ArI(OCOCF3)2 consist of heating
(diacetoxyiodo)arenes in trifluoroacetic acid5a,b or the oxida-
tion of the respective iodoarenes with peroxytrifluoroacetic
acid in trifluoroacetic acid.5b-d A less common procedure
involves the reactions of arenes with I(OCOCF3)3.5e Recently,
Hossain and Kitamura reported a more convenient and safe
method for preparing ArI(OCOCF3)2 in 36-87% yield from
some iodoarenes by using a K2S2O8/CF3CO2H/CH2Cl2 system
at 38 °C for 20 h.6 We have found that Oxone in chloroform
and trifluoroacetic acid is a more efficient oxidizing system
providing [bis(trifluoroacetoxy)iodo]arenes 5a-m from iodo-
arenes 4 in generally excellent yields in 1-4 h at room tem-
perature (Scheme 2). For example, our procedure affords
[Bis(trifluoroacetoxy)iodo]perfluoroalkanes CnF2nþ1I(OC-
OCF3)2 (n = 4, 6, 8, 10, 12) can be conveniently prepared
by the oxidation of the corresponding perfluoroalkyl iodides
with Oxone in trifluoroacetic acid at room temperature and
subsequently converted to the stable [hydroxy(tosyloxy)-
iodo]perfluoroalkanes, CnF2nþ1I(OH)OTs, by treatment
with p-toluenesulfonic acid. This general and convenient
procedure has been further extended to the synthesis of
various [bis(trifluoroacetoxy)iodo]arenes, ArI(OCOCF3)2.
[Bis(acyloxy)iodo]arenes and other polyvalent iodine car-
boxylates belong to the most important class of hyper-
valent iodine compounds, which are widely used in organic
(1) (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis; Academic
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Springer-Verlag, Berlin, 2003. (c) Koser, G. F. Adv. Heterocycl. Chem. 2004,
86, 225–292. (d) Ladziata, U.; Zhdankin, V. V. Synlett 2007, 527–537. (e) Wirth,
T. Angew. Chem., Int. Ed. 2005, 44, 3656–3665. (f) Ladziata, U.; Zhdankin, V. V.
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Miyamoto, K. Eur. J. Org. Chem. 2008, 4229–4239. (p) Zhdankin, V. V. Curr.
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J. A. J. Org. Chem. 2009, 74, 3133–3140.
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V. V. Synthesis 1978, 835–837. (b) Kuehl, C. J.; Bolz, J. T.; Zhdankin, V. V.
Synthesis 1995, 312–316. (c) Zhdankin, V. V.; Kuehl, C. J.; Simonsen, A. J.
J. Org. Chem. 1996, 61, 8272–8276.
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J. D.; Caravatti, G.; Kline, T. B.; Edstrom, E.; Rice, K. C.; Brossi, A.
Tetrahedron 1983, 39, 2393–2397. (c) Zhdankin, V. V.; Scheuller, M. C.;
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DOI: 10.1021/jo902733f
r
Published on Web 02/17/2010
J. Org. Chem. 2010, 75, 2119–2122 2119
2010 American Chemical Society

Zagulyaeva et al.
JOCNote
SCHEME 1. Preparation of [Bis(trifluoroacetoxy)iodo]perfluoro-
alkanes 2 and Tosylates 3
SCHEME 2. Preparation of [Bis(trifluoroacetoxy)iodo]arenes
TABLE 2. Yields and Melting Points of Trifluoroacetates 5a
ArI (4)
Ar
time (h) yield of 5b (%) mp of 5c,d (°C)
TABLE 1. Yields and Melting Points of [Bis(trifluoroacetoxy)iodo]per-
a
b
c
d
e
f
g
h
i
C6H5
4-FC6H4
4-BrC6H4
4-ClC6H4
3-ClC6H4
2-ClC6H4
4-CF3C6H4
3,5-(CF3)2C6H3
4-NO2C6H4
3-NO2C6H4
4-HOOCC6H4
3-HOOCC6H4
C6F5
1.2
1
97
80
94
69
91
97
68
94
69
58
54
41
94
118-120
94-96
123-125
128-130
95-97
98-100
121-123
82 dec
157-159
141-143
109-111
159-161
95.5-96.5e
fluoroalkanes 2a,b and Tosylates 3c
yield of 2d,e
(%)
mp of 2e
(° C)
yield of 3d,e
(%)
mp of 3f
(° C)
1.5
1.5
1.2
1.2
1.5
1.5
1.5
1.5
4
RfI
1a
1b
1c
1d
1e
62
88
67
63
68
55-57
100
99
88
99
98
135-137
141-143
147-149
97-99
65-67
85-87
65.5-66.5
98-99
97g
j
k
l
aProducts 2a-c were prepared by stirring 1a-c (1 g) with Oxone
(1 molar equiv) in trifluoroacetic acid (5 mL) at rt for 24 h at room
temperature. bProducts 2d,e were prepared by stirring 1d,e (0.5 g) with
Oxone (0.5 molar equiv) in trifluoroacetic acid (7 mL) at rt for 48 h.
cTosylates 3 were prepared similarly to the previously reported proce-
dure4b using acetonitrile (3a-c) or acetone (3d,e) as a solvent. dIsolated
yields of analytically pure products. eRecrystallized from trifluoroacetic
acid-hexane, 1:10. fRecrystallized from acetonitrile. gWith decomposi-
tion (turns dark).
4
2
m
aAll reactions of iodoarenes 4a-m (0.5 mmol) were performed at
room temperature in the presence of Oxone (1.5 mol-equiv) in CF3CO2H
(1.5 mL) and CHCl3 (0.5 mL). bIsolated yields of analytically pure
c
products. All previously reported products 5 were identified by com-
parison of their NMR spectra and/or melting points with literature data;
for analytical and spectroscopic characterization of new products (5e, 5f,
5k) see Experimental Section. dRecrystallized from trifluoroacetic acid-
hexane, 1:10. eAdditionally identified by conversion to C6F5I(OH)OTs,
mp 160 °C.
PhI(OCOCF3)2 4a in 97% yield after 1.2 h at room temperature
(Table 2), compared to 76% yield using Hossain and Kitamura’s
procedure.6
The reaction conditions, yields, and melting points of [bis-
(trifluoroacetoxy)iodo]arenes 5 are summarized in Table 2.
Trifluoroacetates 5 were separated from inorganic salts by
extraction with chloroform after evaporation of the reaction
mixture. Analytically pure products 5 were obtained by
recrystallization from hexane in the presence of a small
amount of trifluoroacetic acid. All previously reported pro-
ducts were identified by comparison of their NMR spectra
and melting points with literature data; new products 5e, 5f,
and 5k were identified by NMR spectra and elemental
analysis. The pentafluorophenyl derivative 5m was addition-
ally identified by conversion to [hydroxy(tosyloxy)iodo]-
SCHEME 3. Preparation of [Hydroxy(tosyloxy)iodo]pentafluoro-
benzene 6
evaporated under vacuum and the residue was treated with
acetonitrile (15 mL). The insoluble residue of inorganic salts was
collected by filtration, washed with acetonitrile (10 mL), and
discarded. Evaporation of combined acetonitrile extracts under
reduced pressure afforded microcrystalline crude products 2,
which could be used for the preparation of tosylates 3d,e without
additional purification.
[Bis(trifluoroacetoxy)iodo]perfluorobutane (2a). Reaction of
perfluorobutyl iodide 1a (1.00 g, 2.89 mmol) with Oxone (1.78 g,
2.89 mmol) according to the general procedure afforded 1.02 g
(62%) of product 2a, isolated as a microcrystalline solid. 19F
NMR (282 MHz, CD3CN): δ -75.3 (br s), -76.2 (s), -80.2 (s),
-115.4 (m), -125.0 (m).7
[Bis(trifluoroacetoxy)iodo]perfluorohexane (2b). Reaction of
perfluorohexyl iodide 1b (1.00 g, 2.24 mmol) with Oxone (1.38 g,
2.24 mmol) according to the general procedure afforded 1.32 g
(88%) of product 2b, isolated as microcrystalline solid. Mp:
65-67 °C (lit.2c mp 67 °C dec). 19F NMR (282 MHz, CD3OD): δ
-75.2 (s), -75.8 (s), -80.7 (s), -113.1 (br s), -120.5 (br s),
-122.2 (br s), -125.7 (br s). 13C NMR (selected peaks) (125.6
MHz, CD3OD): δ 115.6 (q, JCF =283 Hz).
pentafluorobenzene 6 using a reaction with TsOH H2O in
3
acetonitrile (Scheme 3).
In conclusion, we have reported a safe, convenient, and
efficient method for preparing fluorous [bis(trifluoroacetoxy)-
iodo]perfluoroalkanes 2 by the oxidation of the corresponding
perfluoroalkyl iodides 1 with Oxone in trifluoroacetic acid at
room temperature. The trifluoroacetates 2 can be further
converted to [hydroxy(tosyloxy)iodo]perfluoroalkanes 3, which
are stable for storage at room temperature and, in contrast to
the trifluoroacetates 2, are not sensitive to light and moisture.
This general and convenient procedure has been further ex-
tended to the synthesis of various [bis(trifluoroacetoxy)iodo]-
arenes 5 in good to excellent yields.
[Bis(trifluoroacetoxy)iodo]perfluorooctane (2c). Reaction of
perfluorooctyl iodide 1c (1.00 g, 1.83 mmol) with Oxone (1.13 g,
1.83 mmol) according to the general procedure afforded 0.95 g
(67%) of product 2c, isolated as microcrystalline solid. 19F NMR
(282 MHz, acetone-d6): δ -74.8 (s), -75.6 (s), -80.5 (s), -113.1
(br s), -120.3 (br s), -121.3 (br s), -122.1 (br s), -125.6 (br s).2a
Experimental Section
Additional experimental details can be found in the Support-
ing Information.
General Procedure for Preparation of [Bis(trifluoroacetoxy)-
iodo]perfluoroalkanes 2a-c. To a solution of an appropriate
iodoperfluoroalkane 1a-c (1 g) in trifluoroacetic acid (5 mL)
was added Oxone (1 molar equiv) under stirring at room
temperature. The reaction mixture was stirred at room tempera-
ture for 24 h. After completion of the reaction, the solvent was
(7) Kasumov, T. M.; Brel, V. K.; Grishin, Y. K.; Zefirov, N. S.; Stang,
P. J. Tetrahedron 1997, 53, 1145–1150.
2120 J. Org. Chem. Vol. 75, No. 6, 2010

Zagulyaeva et al.
JOCNote
General Procedure for Preparation of [Bis(trifluoroacetoxy)-
iodo]perfluoroalkanes 2d,e. To a solution of an appropriate
iodoperfluoroalkane (0.5 g) in trifluoroacetic acid (7 mL) was
added Oxone (0.5 molar equiv) added under stirring at room
temperature. The reaction mixture was stirred at room tempera-
ture for 48 h. After completion of the reaction, the solvent was
evaporated under vacuum and the residue was treated with
acetone (15 mL). The insoluble residue of inorganic salts was
collected by filtration, washed with acetone (10 mL), and
discarded. Evaporation of combined acetone extracts under
reduced pressure afforded a solid crude product 2, which could
be used for the preparation of tosylates 3d,e without additional
purification.
[Bis(trifluoroacetoxy)iodo]perfluorodecane (2d). Reaction of
perfluorodecyl iodide 1d (0.50 g, 0.77 mmol) with Oxone (0.24 g,
0.385 mmol) according to the general procedure afforded 0.43 g
(63%) of product 2d, isolated as a microcrystalline solid. 19F
NMR (282 MHz, acetone-d6): δ -63.9 (s), -75.5 (s), -80.6 (s),
-113.1 (br s), -120.3 (br s), -121.1 (br s), -122.1 (br s), -125.6
(br s).2a
[Bis(trifluoroacetoxy)iodo]perfluorododecane (2e). Reaction of
perfluorododecyl iodide 1e (0.50 g, 0.67 mmol) with Oxone
(0.21 g, 0.385 mmol) according to the general procedure affor-
ded 0.44 g (68%) of product 2e, isolated as a microcrystalline
solid. 19F NMR (282 MHz, acetone-d6): δ -63.9 (s), -75.8 (s),
-80.6 (s), -113.1 (br s), -120.3 (br s), -121.1 (br s), -122.0 (br s),
-125.6 (br s). 13C NMR (selected peaks) (125.6 MHz, acetone-d6):
δ 158.5 (q, JCF = 40.3 Hz), 115.9 (q, JCF =286 Hz).2a
(1.25 molar equiv) in acetone (5-10 mL) was added the appro-
priate trifluoroacetate 2 (0.19-0.43 mmol) at 0 °C. The mixture
was warmed to room temperature and stirred until the forma-
tion of a slightly yellow crystalline precipitate. Evaporation of
the solvent under reduced pressure afforded a pure product.
[Hydroxy(tosyloxy)iodo]perfluorodecane (3d). Reactionof [bis-
(trifluoroacetoxy)iodo]perfluorodecane 2d (0.375 g, 0.43 mmol)
according to the general procedure afforded 0.355 g (99%) of
product 3d, isolated as a microcrystalline solid. Mp: 97-99 °C.
1H NMR (500 MHz, acetone-d6): δ 7.78 (d, J = 8.0 Hz, 2H),
7.39 (d, J = 8.0 Hz, 2H), 2.42 (s, 3H). 13C NMR (selected
peaks) (125.6 MHz, acetone-d6): δ 144.2, 138.9, 130.4, 127.5,
21.4. 19F NMR (282 MHz, acetone-d6): δ -63.9 (s), -80.6
(s), -113.1 (s), -120.3 (s), -121.2 (s), -122.2 (br s), -125.7 (s).
Anal. Calcd for C17H8F21IO4S: C, 24.48; H, 0.97. Found: C,
24.21; H, 0.90.
[Hydroxy(tosyloxy)iodo]perfluorododecane (3e). Reaction of
[bis(trifluoroacetoxy)iodo]perfluorododecane 2e (0.19 g, 0.195
mmol) according to the general procedure afforded 0.18 g (98%)
of product 3e, isolated as a microcrystalline solid. Mp: 97 °C dec.
1H NMR (500 MHz, acetone-d6): δ 7.78 (d, J=8.1 Hz, 2H), 7.39
(d, J = 8.1 Hz, 2H), 2.42 (s, 3H). 13C NMR (selected peaks)
(125.6 MHz, acetone-d6): δ 130.3, 127.5, 21.4. 19F NMR (282
MHz, acetone-d6): δ -63.9 (s), -80.5 (s), -113.0 (s), -120.3 (s),
-121.1 (s), -122.1 (s), -125.6 (s). Anal. Calcd for C19H8F25-
IO4S: C, 24.43; H, 0.86; F, 50.84; S, 3.43. Found: C, 24.02; H,
0.89; F, 50.49; S, 3.32.
General Procedure for Preparation of [Bis(trifluoroacetoxy)-
iodo]arenes 5. To a solution of an appropriate iodoarene 4 (0.5
mmol) in a mixture of trifluoroacetic acid (1.5 mL) and chloro-
form (0.5 mL) was added Oxone (1.5 molar equiv) under stirring
at room temperature. The reaction mixture was stirred at room
temperature for a period of time as indicated in Table 1 (the
reaction was monitored by TLC using hexane/EtOAc 3:1 as
eluent by disappearance of the iodoarene). After completion of
the reaction, the solvent was evaporated under vacuum, and the
residue was treated with chloroform (10 mL). The insoluble
residue of inorganic salts was collected by filtration, washed
with chloroform (5 mL), and discarded. Evaporation of com-
bined chloroform extracts under reduced pressure afforded
crude products 4, which could be further purified by recrystalli-
zation from CF3CO2H/hexane, 1:10.
[Bis(trifluoroacetoxy)iodo]benzene (5a). Reaction of iodoben-
zene 4a (0.10 g, 0.50 mmol) according to the general procedure
afforded 0.21 g (97%) of product 5a, isolated as a microcrystal-
line solid. Mp: 118-120 °C (lit.6 mp 119-120 °C). 1H NMR (300
MHz, CDCl3/CF3CO2D, 22:1): δ 8.22 (d, J=7.8 Hz, 2H), 7.75
(t, J = 7.8 Hz, 1H), 7.64 (t, J = 7.8 Hz, 2H). 13C NMR (125.6
MHz, CDCl3): δ 161.1 (q, JCF = 42 Hz), 135.2, 133.7, 132.1,
122.8, 112.9 (q, JCF =287 Hz).
General Procedure for Preparation of [Hydroxy(tosyloxy)-
iodo]perfluoroalkanes 3a-c. To a stirred solution of TsOH H2O
3
(1.25 molar equiv) in acetonitrile (5-10 mL) was added the
appropriate trifluoroacetate 2 (1.14-1.82 mmol) at 0 °C. The
mixture was warmed to room temperature and stirred until
formation of a white crystalline precipitate. Evaporation of the
solvent under reduced pressure afforded a crude product 3.
Analytically pure materials were obtained by recrystallization
from acetonitrile.
[Hydroxy(tosyloxy)iodo]perfluorobutane (3a). Reactionof[bis-
(trifluoroacetoxy)iodo]perfluorobutane 2a (0.92 g, 1.60 mmol)
according to the general procedure afforded 0.85 g (100%) of
product 3a, isolated as a microcrystalline solid. Mp: 135-137 °C
(lit.4b mp137-139 °C). 1H NMR(500MHz, CD3CN/DMSO-d6,
20:1): δ 7.70 (d, J = 7.4 Hz, 2H), 7.28 (d, J = 7.4 Hz, 2H), 2.39
(s, 3H). 13C NMR (125.6 MHz, CDCl3): δ 143.6, 137.2, 129.8,
125.5, 21.4. 19F NMR (282 MHz, CD3CN/DMSO-d6, 20:1): δ
-80.5 (s), -83.7 (s), -116.2 (s), -125.1 (s).
[Hydroxy(tosyloxy)iodo]perfluorohexane (3b). Reaction of [bis-
(trifluoroacetoxy)iodo]perfluorohexane 2a (1.22 g, 1.82 mmol)
according to the general procedure afforded 1.14 g (99%) of
product 3b, isolated as a microcrystalline solid. Mp: 141-143 °C
(lit.4b mp 142-144 °C). 1H NMR (500 MHz, CD3CN/DMSO-d6,
20:1): δ 7.68 (d, J=8.4 Hz, 2H), 7.26 (d, J=8.4 Hz, 2H), 2.40 (s,
3H). 13C NMR (selected peaks) (125.6 MHz, CD3CN/DMSO-d6,
22:1): δ 140.5, 128.9, 125.9, 20.5. 19F NMR (282 MHz, CD3CN/
DMSO-d6, 20:1): δ -63.7 (s), -80.2 (s), -112.8 (br s), -120.3 (s),
-121.9 (br s), -125.3 (br s).
1-[Bis(trifluoroacetoxy)iodo]-3-chlorobenzene (5e). Reaction
of 1-chloro-3-iodobenzene 4e (0.12 g, 0.50 mmol) under general
conditions afforded 0.21 g (91%) of product 5e, isolated as a
microcrystalline solid. Mp: 95-97 °C. 1H NMR (300 MHz,
CDCl3/CF3CO2D, 22:1): δ 8.21 (s, 1H), 8.11 (d, J=8.5 Hz, 1H),
7.72 (d, J = 8.5 Hz, 1H), 7.59 (t, J = 8.5 Hz, 1H). 13C NMR
(125.6 MHz, CDCl3): δ 161.3 (q, JCF = 42 Hz), 136.8, 134.7,
133.1, 132.8, 132.1, 121.8, 112.9 (q, JCF =288 Hz). Anal. Calcd
for C10H4ClF6IO4: C, 25.86; H, 0.87; I, 27.32; F, 24.54. Found:
C, 25.64; H, 0.89; I, 27.55; F, 24.30.
[Hydroxy(tosyloxy)iodo]perfluorooctane (3c). Reaction of [bis-
(trifluoroacetoxy)iodo]perfluorooctane 2c (0.877 g, 1.14 mmol)
according to the general procedure afforded 0.73 g (88%) of
product, isolated as a microcrystalline solid. Mp: 147-149 °C
(lit.4b mp 147-149 °C). 1H NMR (500 MHz, CD3CN/DMSO-d6,
20:1): δ 7.68 (d, J=8.5 Hz, 2H), 7.24 (d, J=8.5 Hz, 2H), 2.39 (s,
3H). 13C NMR (selected peaks) (125.6 MHz, CD3CN/DMSO-d6,
22:1): δ 140.1, 128.8, 125.9, 20.5. 19F NMR (282 MHz, CD3CN/
DMSO-d6, 20:1): δ -75.4 (s), -80.2 (s), -82.7 (s), -112.9 (s),
-119.9 (s), -121.0 (s), -121.9 (br s), -125.3 (s).
1-[Bis(trifluoroacetoxy)iodo]-2-chlorobenzene (5f). Reaction
of 1-chloro-2-iodobenzene 4f (0.12 g, 0.50 mmol) under general
conditions afforded 0.23 g (97%) of product 5f, isolated as a
1
microcrystalline solid. Mp: 98-100 °C. H NMR (300 MHz,
CDCl3/CF3CO2D, 22:1): δ 8.37 (d, J=8.1 Hz, 1H), 7.85 (d, J=
8.1 Hz, 1H), 7.72 (t, J=8.1 Hz, 1H), 7.48 (t, J=8.1 Hz, 1H). 13
C
NMR (125.6 MHz, CDCl3): δ 161.3 (q, JCF = 41 Hz), 138.7,
137.6, 135.7, 130.6, 129.8, 126.1, 113.0 (q, JCF =286 Hz).
General Procedure for Preparation of [Hydroxy(tosyloxy)-
iodo]perfluoroalkanes 3d,e. To a stirred solution of TsOH H2O
3
J. Org. Chem. Vol. 75, No. 6, 2010 2121

Zagulyaeva et al.
JOCNote
1-[Bis(trifluoroacetoxy)iodo]-3,5-bis(trifluoromethyl)benzene (5h).
Reaction of 1-iodo-3,5-bis(trifluoromethyl)benzene 4h (0.17 g,
0.50 mmol) under general conditions afforded 0.27 g (94%) of
product 5h, isolated as a microcrystalline solid. Mp: 82 °Cdec(lit.5c
mp 82 °C dec). 1H NMR (300 MHz, CDCl3/CF3CO2D, 22:1): δ
8.60 (s, 2H), 8.21 (s, 1H). 13C NMR (125.6 MHz, CDCl3): δ 161.5
initially isolated as an oil, which was sublimed to afford a micro-
crystalline solid. Mp: 95.5-96.5 °C (lit.9 mp 96 °C). 19F NMR
(300 MHz, DMSO-d6): δ -73.9 (s), -123.6 (s), -144.8 (s),
-157.3 (s). 13C NMR (125.6 MHz, DMSO-d6): δ 159.7 (q, JCF
37 Hz), 148.2 (m), 146.3 (m), 138.2 (m), 136.2 (m), 115.6 (q, JCF
=
=
289 Hz). Crude product 5m was additionally identified by conver-
sion to [hydroxy(tosyloxy)iodo]pentafluorobenzene 6.
(q, JCF =40 Hz), 135.2 (q, JCF =35 Hz), 134.83, 127.5 (q, JCF
=
4 Hz), 121.9 (q, JCF =274 Hz), 121.5, 112.9 (q, JCF = 287 Hz).
4-[Bis(trifluoroacetoxy)iodo]benzoic Acid (5k). Reaction of 4-
iodobenzoic acid 4k (0.12 g, 0.50 mmol) under general condi-
tions afforded 0.13 g (54%) of product 5k, isolated as a micro-
crystalline solid. Mp: 109-111 °C. 1H NMR (300 MHz, CDCl3/
CF3CO2D, 22:1): δ 8.34 (s, 4H). 13C NMR (125.6 MHz, CDCl3/
CF3CO2D, 60:1): δ 170.0, 160.7 (q, JCF =43 Hz), 135.2, 133.7,
133.2, 127.5, 112.9 (q, JCF =288 Hz).
3-[Bis(trifluoroacetoxy)iodo]benzoic Acid (5l). Reaction of 3-
iodobenzoic acid (0.12 g, 0.5 mmol) under general conditions
afforded 0.10 g (41%) of product, isolated as a microcrystalline
solid. Mp: 159-161 °C. 1H NMR (300 MHz, CDCl3/CF3CO2D,
22:1): δ 8.96 (s, 1H), 8.47-8.52 (m, 2H), 7.82 (t, J=8.2 Hz, 1H).
13C NMR (125.6 MHz, CDCl3/CF3CO2D, 60:1): δ 169.2, 160.3
(q, JCF =43 Hz), 140.1, 136.8, 135.2, 132.4, 132.3, 122.2, 112.9
(q, JCF =290 Hz).8
[Hydroxy(tosyloxy)iodo]pentafluorobenzene (6). Reaction of
[bis(trifluoroacetoxy)iodo]pentafluorobenzene 5m (0.20 g, 0.385
mmol) with TsOH H2O according to the general procedure for
3
preparation of tosylates 3a-c afforded 0.17 g (94%) of product 6,
1
isolated as a microcrystalline solid. Mp: 160 °C dec. H NMR
(500 MHz, CD3CN/DMSO-d6, 20:1): δ 7.57 (d, J= 8.7 Hz, 2H),
7.24 (d, J = 8.7 Hz, 2H), 2.39 (s, 3H). 13C NMR (125.6 MHz,
CDCl3/DMSO-d6, 24:1): δ 141.1, 140.4, 128.8, 125.9, 21.3. 19F
NMR (282 MHz, CD3CN/DMSO-d6, 20:1): δ -120.5 (s), -153.9
(s), -160.4 (s). Anal. Calcd for C13H8F5IO4S: C, 32.38; H, 1.67; S,
6.65. Found: C, 32.73; H, 1.67; S, 6.82.
Acknowledgment. This work was supported by a research
grant from the National Science Foundation.
Supporting Information Available: Details of the experi-
mental procedures and spectroscopic data of the products. This
material is available free of charge via the Internet at http://
pubs.acs.org.
1-[Bis(trifluoroacetoxy)iodo]pentafluorobenzene (5m). Reac-
tion of iodopentafluorobenzene 4m (0.15 g, 0.5 mmol) under
general conditions afforded 0.245 g (94%) of crude product 5m,
(8) Yusubov, M. S.; Funk, T. V.; Chi, K.-W.; Cha, E.-H.; Kim, G. H.;
Kirschning, A.; Zhdankin, V. V. J. Org. Chem. 2008, 73, 295–297.
(9) Patzelt, H.; Woggon, W. D. Helv. Chim. Acta 1992, 75, 523–530.
2122 J. Org. Chem. Vol. 75, No. 6, 2010