1-[hydroxy(sulfonyloxy)iodo]-1H,1H-perfluoroalkanes: Stable, fluoroalkyl analogs of Koser's reagent

Article abstract of DOI:10.1021/jo961336n

1-[Hydroxy(sulfonyloxy)iodo]-1H,1H/-perfluoroalkanes 3 [R_fCH₂I(OH)OSO₂R; R = CH₃, CH₃, p-CH₃C₆H₄, R_f = CF₃, C₂F₅] can be pr

Full text of DOI:10.1021/jo961336n

8272
J . Org. Chem. 1996, 61, 8272-8276
1-[Hyd r oxy(su lfon yloxy)iod o]-1H,1H-p er flu or oa lk a n es: Sta ble,
F lu or oa lk yl An a logs of Koser ’s Rea gen t
Viktor V. Zhdankin,* Chris J . Kuehl, and Angela J . Simonsen
Chemistry Department, University of Minnesota-Duluth, Duluth, Minnesota 55812
Received J uly 15, 1996X
1-[Hydroxy(sulfonyloxy)iodo]-1H,1H-perfluoroalkanes 3 [RfCH2I(OH)OSO2R; R ) CH3, CF3, p-CH3C6H4,
Rf ) CF3, C2F5] can be prepared in two steps from the appropriate iodofluoroalkanes by oxidation
with peroxytrifluoroacetic acid and subsequent reaction with TsOH, MsOH, or Me3SiOTf. The
tosylate derivative 3a reacts with silyl enol ethers under mild conditions to give the respective
R-(tosyloxy) ketones. A similar reaction of cyclohexene furnishes cis-1,2-bis(tosyloxy)cyclohexane
as the major product. Triflates 3c,f react with (trimethylsilyl)arenes under mild conditions to afford
the respective (fluoroalkyl) (aryl)iodonium triflates 7, while the analogous reaction with alkynyltri-
methylsilanes leads to novel (fluoroalkyl)(alkynyl)iodonium salts 8.
Ta ble 1.
In tr od u ction
1-[Hyd r oxy(su lfon yloxy)iod o]-1H,1H-p er flu or oa lk a n es 3
There is considerable current interest and research
activity in the development of new reagents and synthetic
methods based on the organic chemistry of hypervalent
iodine.1 The overwhelming majority of the known, stable
organic polyvalent iodine compounds have a benzene ring
as a carbon ligand linked to the iodine atom. Derivatives
of polyvalent iodine with an alkyl substituent at the
iodine generally are highly unstable and can exist only
as short-lived reactive intermediates in the oxidation of
alkyl iodides. However, introduction of an electron-
withdrawing substituent in the alkyl moiety may lead
to significant stabilization of the molecule. Especially
interesting and useful representatives of such stabilized
compounds with I-Csp3-bonding are (fluoroalkyl)iodanes.1a,b
The first representatives of stable (fluoroalkyl)iodanes,
namely 1-[bis(trifluoroacetoxy)iodo]perfluoroalkanes, RfI(O-
COCF3)2, and (perfluoroalkyl)(phenyl)iodonium salts,
RfIPhX, were reported by Yagupolskii and co-workers in
1970.2 A few years later, Umemoto and co-workers
demonstrated that (fluoroalkyl)(phenyl)iodonium sul-
fonates can be used as efficient electrophilic fluoroalky-
lating reagents.3,4 One of the more recent developments
in the area of (fluoroalkyl)iodonium chemistry has been
product
n
R
mp, °C
yield,a
%
3a
3b
3c
3d
3e
3f
1
1
1
2
2
2
Tol
Me
CF3
Tol
Me
CF3
123-125
105-107
58-61
124-125
97-99
105-109
90
86
70
96
97
92
a
Preparative yield.
the preparation of 1-(dichloroiodo)-1H,1H-perfluoro-
alkanes, RfCH2ICl2, relatively stable alkyl derivatives of
trivalent iodine, that can serve as precursors to useful
(1H,1H-perfluoroalkyl)(phenyl)iodonium triflates.5 How-
ever, these compounds, RfCH2ICl2, have only limited
synthetic value since they generally require conversion
to more electrophilic trifluoroacetates by AgOCOCF3.5a
In this paper we wish to report the preparation and
properties of sulfonates 3a -f (Table 1),6 which are more
stable then 1-(dichloroiodo)-1H,1H-perfluoroalkanes and
have a useful reactivity pattern, similar to Koser’s
reagent,1a-c PhI(OH)OTs.
Resu lts a n d Discu ssion
X Abstract published in Advance ACS Abstracts, November 1, 1996.
(1) (a) Varvoglis, A. The Organic Chemistry of Polycoordinated
Iodine; VCH Publishers, Inc.: New York, 1992. (b) Stang, P. J .;
Zhdankin, V. V. Chem. Rev. 1996, 96, 1123. (c) Moriarty, R. M.; Vaid,
R. K.; Koser, G. F. Synlett 1990, 365. (d) Moriarty, R. M.; Vaid, R. K.
Synthesis 1990, 431. (e) Merkushev, E. B. Russian Chem. Rev. 1987,
56, 826. (f) Moriarty, R. M.; Prakash, O. Acc. Chem. Res. 1986, 19,
244. (g) Ochiai, M.; Nagao, Y. Yuki Gosei Kagaku Kyokai Shi 1986,
44, 660. (h) Varvoglis, A. Synthesis 1984, 7099. (i) Koser, G. F. In
The Chemistry of Functional Groups, Suppl. D; Patai, S.; Rappoport,
Z., Eds.; Wiley-Interscience: New York, 1983; Chapters 18 and 25, pp
721-811 and 1265-1351. (j) Prakash, O.; Saini, N.; Sharma, P. K.
Synlett 1994, 221. Prakash, O.; Saini, N.; Sharma, P. K. Heterocycles
1994, 38, 409. Prakash, O.; Singh, S. P. Aldrichim. Acta 1994, 27, 15.
Prakash, O. Aldrichim. Acta 1995, 28, 63. (k) Stang, P. J . Angew.
Chem., Int. Ed. Engl. 1992, 31, 274. Stang, P. J . In The Chemistry of
Triple-Bonded Functional Groups, Supplement C2; Patai, S., Ed.; J ohn
Wiley & Sons, Ltd.: Chichester, 1994; Vol. 2, Chapter 20, pp 1164-
1182. Stang, P. J . In Modern Acetylene Chemistry; Stang, P. J .,
Diederich, F., Eds.; VCH Publishers: Weinheim, 1995; Chapter 3, pp
67-98. (1) Koser, G. F. In The Chemistry of Halides, Pseudo-Halides
and Azides, Suppl. D2; Patai, S., Rappoport, Z., Eds.; Wiley-Inter-
science: Chichester, 1995; Chapter 21, pp 1173-1274.
Sulfonates 3a -f can be conveniently prepared in two
steps from the commercially available 1H,1H-perfluoro-
alkyl iodides 1 (Scheme 1). In the first step, starting
iodides 1 are oxidized with peroxytrifluoroacetic acid to
trifluoroacetates 2 in almost quantitative yield by a
known procedure.4b The subsequent treatment of tri-
fluoroacetates 2 with the monohydrate of p-toluene-
sulfonic acid or methanesulfonic acid in acetonitrile at
low temperature results in the formation of tosylates 3a ,d
or mesylates 3b,e in high yield. In contrast to starting
trifluoroacetates 2, tosylates 3a ,d have a substantially
higher thermal stability, melting at about 124 °C without
decomposition. Both tosylates 3a ,d and mesylates 3b,e
are not water sensitive, can be purified by crystallization
(4) (a) Umemoto, T.; Gotoh, Y. Bull. Chem. Soc. J pn. 1987, 60, 3823.
Umemoto, T.; Gotoh, Y. Bull. Chem. Soc. J pn. 1991, 64, 2008. (b)
Umemoto, T.; Gotoh, Y. Bull. Chem. Soc. J pn. 1987, 60, 3307.
(5) (a) Montanari, V.; Resnati, G. Tetrahedron Lett. 1994, 35, 8015.
(b) Bravo, P.; Montanari, V.; Resnati, G.; DesMarteau, D. D. J . Org.
Chem. 1994, 59, 6093.
(2) (a) Lyalin, V. V.; Orda, V. V.; Alekseyeva, L. A.; Yagupolskii, L.
M. J . Org. Chem. USSR 1970, 6, 3171. (b) Lyalin, V. V.; Orda, V. V.;
Alekseyeva, L. A.; Yagupolskii, L. M. J . Org. Chem. USSR 1971, 7,
1524. (c) Yagupolskii, L. M.; Maletina, I. I.; Kondratenko, N. V.; Orda,
V. V. Synthesis 1978, 835.
(6) Preliminary communication: Zhdankin, V. V.; Kuehl, C. J .;
Simonsen, A. J . Tetrahedron Lett. 1995, 36, 2203.
(3) Umemoto, T. Chem. Rev. 1996, 96, 1757.
S0022-3263(96)01336-9 CCC: $12.00 © 1996 American Chemical Society

Stable, Fluoroalkyl Analogs of Koser’s Reagent
J . Org. Chem., Vol. 61, No. 23, 1996 8273
Sch em e 1
Sch em e 3
Ta ble 2. (1H,1H-P er flu or oa lk yl)(a r yl)iod on iu m Tr ifla tes
7
product
n
Ar
mp, °C
yield,a
%
7a 4b
7b
7c
1
1
1
1
1
2
2
2
2
2
Ph
91-93 (88-89)4b
88-90
85
62
72
78
77
71
75
75
65
74
4-TMSC6H4
2-MeC6H4
4-MeC6H4
4-MeOC6H4
Ph
4-TMSC6H4
2-MeC6H4
4-MeC6H4
4-MeOC6H4
75-77
7d
7e
77-80
92-94
Sch em e 2
7f4b
7g
7h
7i
127-129 (130)4b
130-132
106-108
124-126
147-148
7j
a
Preparative yield.
reactivity of tosylate 3a compared to PhI(OH)OTs. It is
also interesting to compare the reactivity of tosylate 3a
and its perfluoroalkylated analog, C4F9I(OH)OTs,9,10 in
the reaction with cyclohexene. In contrast to tosylate 3a
and Koser’s reagent, C4F9I(OH)OTs reacts with cyclo-
hexene under similar conditions to afford trans-1-iodo-
2-(tosyloxy)cyclohexane, but not cis-ditosylate 6, as the
major product.9
Similar to their phenyl-substituted analogs, com-
pounds 3 can be used for the preparation of iodonium
salts via reaction with the respective trimethylsilane
derivatives. We have found that triflates 3c and 3f can
serve as convenient precursors to (1H,1H-perfluoroalkyl)-
(aryl)iodonium triflates 7 (Scheme 3, Table 2) which are
useful electrophilic fluoroalkylating agents.4,5 Reagents
3c,f smoothly react with aryltrimethylsilanes in meth-
ylene chloride under very mild conditions to give iodo-
nium salts 7 in high yields. Products 7 were crystallized
from ether-hexane and characterized by IR, NMR, and
elemental analysis. In contrast to previously reported
methods,4,5 the preparation of 7 does not require the
presence of triflic acid. Therefore, our method can, in
principle, be generalized to acid-sensitive substrates.
It is noteworthy that triflates 3c,f are more reactive
toward arylsilanes than the previously reported (perfluo-
roalkyl)iodonium triflates, CnF2n+1I(OH)OTf.10 Reaction
of CnF2n+1I(OH)OTf with ArTMS generally require the
presence of Me3SiOTf or trifluoroacetic acid as a catalyst,
whereas triflates 3c,f smoothly react with ArTMS with-
out the presence of a catalyst and at low temperatures.
Under similar conditions, triflates 3c,f react with
various substituted (trimethylsilyl)acetylenes to afford
novel (fluoroalkyl)(alkynyl)iodonium salts 8 (Table 3).
Products 8 are substantially less stable than their aryl-
substituted analogs, decomposing after only 2-3 days of
storage in a refrigerator. Nevertheless, all compounds
8 were characterized by their IR and NMR spectra. All
IR spectra displayed the typical CtC stretch1k between
2165 and 2145 cm-1, along with CF absorbances from
from acetonitrile, and can be stored for several months
in a refrigerator. The analogous triflates 3c,f were
prepared in good yield by the reaction of trifluoroacetates
2 with trimethylsilyl triflate in dichloromethane and were
isolated as colorless, stable, nonhygroscopic solids. The
structures of compounds 3a -f were determined by IR,
NMR, and elemental analysis. In particular, the 1H
NMR displayed the characteristic signals of methylene
protons at δ ) 4.9-5 ppm as a quartet (n ) 1) or a triplet
(n ) 2) with J H-F ) 10 Hz. The broad signal of the
hydroxyl proton was observed at about 3 ppm for all
compounds 3, as well as the respective signals of Ts or
Ms groups for 3a ,d and 3b,e.
Investigation of chemical properties of compounds 3
has shown that their reactivity pattern is similar to
Koser’s reagent, PhI(OH)OTs, and Zefirov’s reagent,
PhI(OTf)O(OTf)IPh.1a-c Similar to their phenyl-substi-
tuted analogs, compounds 3 are highly reactive toward
electron-rich organic substrates, such as silyl enol ethers,
alkenes, aryltrimethylsilanes, and alkynyltrimethyl-
silanes. We have found that reagent 3a reacts with the
silyl enol ethers of acetophenone and cyclohexanone
under mild conditions to afford R-(tosyloxy) ketones 4 and
5 as major products (Scheme 2). These reactions give
only volatile byproducts (bp of CF3CH2I is 55 °C), which
significantly facilitates reaction workup. Products 4 and
5 were identified by comparison of their melting points
and NMR spectra with literature data.7
Similar to Koser’s reagent, tosylate 3a reacts with
cyclohexene to afford cis-1,2-bis(tosyloxy)cyclohexane 68
(Scheme 2) as the major product. This reaction is
completed in 3-4 h at 0 °C, while the analogous reaction
of Koser’s reagent requires 4 days at room temperature
for completion, which indicates substantially higher
1250 to 1000 cm-1 1H NMR spectra showed the signal
.
(9) Zefirov, N. S.; Zhdankin, V. V.; Dan’kov, Yu.V.; Sorokin, V. D.;
Semerikov, V. N.; Koz’min, A. A.; Caple, R.; Berglund, B. Tetrahedron
Lett. 1986, 27, 3971.
(10) Zhdankin, V. V.; Kuehl, C. Tetrahedron Lett. 1994, 35, 1809.
Zhdankin, V. V.; Kuehl, C. J .; Bolz, J . T.; Zefirov, N. S. Mendeleev
Commun. 1994, 1651. Kuehl, C. J .; Bolz, J . T.; Zhdankin, V. V.
Synthesis 1995, 312.
(7) Koser, G. F.; Relenyi, A. G.; Kalos, A. N.; Rebrovic, L.; Wettach,
R. H. J . Org. Chem. 1982, 47, 2487.
(8) Rebrovic, L.; Koser, G. F. J . Org. Chem. 1984, 49, 2462.

8274 J . Org. Chem., Vol. 61, No. 23, 1996
Zhdankin et al.
Ta ble 3. (1H,1H-P er flu or oa lk yl)(a lk yn yl)iod on iu m
1H,1H-perfluoroalkanes 2 were prepared by oxidation of the
appropriate, commercial iodofluoroalkanes with peroxytri-
fluoroacetic acid according to a known procedure4b and were
used without additional purification. (Trimethylsilyl)arenes
were prepared from the corresponding bromo- or iodoarenes
by lithiation with butyllithium followed by quenching with
chlorotrimethylsilane.11 Methylene chloride and acetonitrile
were distilled from CaH2 immediately prior to use. Other
solvents were of commercial quality from freshly opened
containers. The reaction flasks were flame-dried and flushed
with nitrogen.
Tr ifla tes 8
product
n
R
mp, °C
yield,a
%
8a
8b
8c
8d
8e
1
1
1
2
2
t-Bu
TMS
Ph
t-Bu
Ph
70-72
54-57
74
70
65
76
55
66-68
122-124
101-102
a
Preparative yield.
Sch em e 4
1-[Hydr oxy(tosyloxy)iodo]-1H,1H-per flu or oeth an e (3a):
Typ ica l P r oced u r e. To a stirred solution of TsOH‚H2O (0.23
g, 1.2 mmol) in acetonitrile (15-20 mL) was added 1-[bis-
(trifluoroacetoxy)iodo]-1H,1H-perfluoroethane (2a ) (0.500 g,
1.15 mmol) at -30 °C. The mixture was warmed to room
temperature and stirred until a white crystalline precipitate
of 3a formed. The product was filtered, washed with dry CH2-
Cl2 (10 mL), and dried in vacuo to afford 0.41 g (90%) of
analytically pure 3a as white needles: mp 123-124 °C; IR
(KBr) 3467, 3044, 2944, 2922, 1383, 1289, 1250, 1183, 1128,
of RfCH2 protons as a quartet or a triplet at 4.7-4.9 ppm
with J H-F ) 10 Hz. In the 13C NMR spectrum of 8, the
acetylenic signals have chemical shifts -8 to 20 (CtCI)
and 94 to 104 (CtCI) ppm, which are typical of alkyn-
yliodonium salts.1k
1
1039, 1011 cm-1; H NMR (CDCl3/CD3CN, 5:1) δ 7.65 (d, 2H,
J ) 8 Hz), 7.15 (d, 2H, J ) 8 Hz), 4.93 (q, 2H, J H-F ) 10 Hz),
2.8 (br s, 1H, OH), 2.3 (s, 3H). Anal. Calcd for C9H10IF3O4S:
C, 27.15; H, 2.53; I, 31.87. Found: C, 27.17; H, 2.54; I, 31.78.
1-[H yd r oxy(t osyloxy)iod o]-1H ,1H -p er flu or op r op a n e
(3d ). According to the above typical procedure, TsOH‚H2O
(0.23 g, 1.2 mmol) was reacted with 1-bis(trifluoroacetoxy)-
iodo]-1H,1H-perfluoropropane (2b) (0.559 g, 1.15 mmol) to
afford 0.494 g (96%) of 3d as white needles: mp 124-125 °C;
IR (KBr) 3467, 3044, 2944, 2922, 1383, 1289, 1250, 1183, 1128,
Considering the useful properties of alkynyliodonium
salts,1k,1 the preparation of products 8a -e is of particular
interest. It is noteworthy that the previously reported
(perfluoroalkyl)iodonium triflates, CnF2n+1I(OH)OTf10 did
not react with (trimethylsilyl)acetylenes, and we were
therefore not able to prepare the analogous (perfluoro-
alkyl)(alkynyl)iodonium salts, CnF2n+1I(CtCR)OTf.
It should be emphasized that reactivity of sulfonates
3 toward organic substrates is different from the previ-
ously reported [hydroxy(sulfonyloxy)iodo]perfluoroalkanes,
CnF2n+1I(OH)OSO2R. Specifically, C4F9I(OH)OTs reacts
with cyclohexene to afford trans-1-iodo-2-(tosyloxy)cyclo-
hexane,9 while a similar reaction of CF3CH2I(OH)OTs
gives cis-ditosylate 6 as the major product. This reactiv-
ity difference is most likely explained by the higher
electronegativity of the CnF2n+1 group compared to the
CnF2n+1CH2 moiety. As a result, the C-I bond in
CnF2n+1-I(OH)OX has more ionic character than in
CnF2n+1CH2-I(OH)OX and will cleave easier under polar
conditions. In general, we can speculate that the C-I
bond polarities in 3 and in Koser’s reagent are similar,
which explains the observed similarities in their reactiv-
ity.
In conclusion, we have prepared and isolated as
individual, stable compounds 1-[hydroxy(sulfonyloxy)-
iodo]-1H,1H-perfluoroalkanes 3, a new structural type of
iodine(III) sulfonate. These compounds have a reactivity
pattern similar to Koser’s reagent and therefore are
useful for vicinal oxytosylations and for the synthesis of
R-(tosyloxy) ketones. Triflates 3c,f react with (trimeth-
ylsilyl)arenes under mild conditions to afford the respec-
tive (fluoroalkyl)(aryl)iodonium triflates 7, while the
analogous reaction with alkynyltrimethylsilanes leads to
novel (fluoroalkyl)(alkynyl)iodonium salts 8.
1039, 1011 cm-1 1H NMR (CDCl3/DMSO-d6, 5:1) δ 7.67 (d,
;
2H, J ) 8 Hz), 7.17 (d, 2H, J ) 8 Hz), 4.73 (t, 2H, J H-F ) 10
Hz), 2.36 (s, 3H), 2.08 (br s, 1H, OH). Anal. Calcd for
C10H10IF5O4S: C, 26.80; H, 2.25; I, 28.32. Found: C, 26.47;
H, 2.15; I, 28.04.
1-[Hyd r oxy(m eth a n esu lfon yloxy)iod o]-1H,1H-p er flu o-
r oeth a n e (3b): Typ ica l P r oced u r e. To a stirred solution
of 1-[bis(trifluoroacetoxy)iodo]-1H,1H-perfluoroethane (2a ) (0.5
g, 1.15 mmol) in acetonitrile (15-20 mL) was added neat
methanesulfonic acid (0.1 mL, 1.4 mmol) dropwise at -30 °C.
The mixture was then warmed to room temperature and
stirred until a white crystalline precipitate of 3b formed. The
product was filtered, washed with dry CH2Cl2 (10 mL), and
dried in vacuo to afford 0.32 g (86%) of analytically pure 3b
as white needles: mp 105-107 °C; IR (KBr) 3433, 2944, 1233,
1189, 1117, 1061 cm-1 1H NMR (CDCl3/CD3CN, 5:1) δ 4.91
;
(q, 2H, J H-F ) 10 Hz), 3.2 (br s, 1H, OH), 2.9 (s, 3H). Anal.
Calcd for C3H6IF3O4S: C, 11.19; H, 1.88; I, 39.41. Found: C,
11.09; H, 1.83; I, 39.47.
1-[Hyd r oxy(m eth a n esu lfon yloxy)iod o]-1H,1H-p er flu o-
r op r op a n e (3e). According to the above typical procedure,
1-[bis(trifluoroacetoxy)iodo]-1H,1H-perfluoropropane (2b) (0.559
g, 1.15 mmol) was reacted with neat methanesulfonic acid (0.1
mL, 1.4 mmol) to afford 0.415 g (97%) of analytically pure 3e
as white needles: mp 107-109 °C; IR (KBr) 3433, 2944, 1233,
1189, 1117, 1061 cm-1; 1H NMR (CDCl3/DMSO-d6, 5:1) δ 7.35
(br s, 3H, OH), 4.79 (t, 2H, J H-F ) 10 Hz), 2.81 (s, 3H). Anal.
Calcd for C4H6IF5O4S‚H2O: C, 12.32; H, 2.07; I, 33.53.
Found: C, 12.70; H, 2.08; I, 33.80.
1-[Hydr oxy[(tr iflu or om eth an esu lfon yl)oxy]iodo]-1H,1H-
p er flu or oeth a n e (3c): Typ ica l P r oced u r e. To a stirred
mixture of 1-[bis(trifluoroacetoxy)iodo]-1H,1H-perfluoroethane
(2a ) (0.559 g, 1.15 mmol) in 15-20 mL of dry CH2Cl2 was
added 0.3 mL (1.5 mmol) of trimethylsilyl triflate at -30 °C.
The resulting mixture was warmed to room temperature and
stirred until a white precipitate of 3c formed. The product
was filtered, washed with dry hexane (10 mL), and dried under
high vacuum to afford 0.3 g (70%) of analytically pure 3c as a
white waxy solid: mp 111-113 °C dec; IR (KBr) 3444, 2956,
Exp er im en ta l Section
Gen er a l P r oced u r es. All melting points were determined
in an open capillary tube and are uncorrected. NMR spectra
were recorded at 200 MHz (1H NMR) and 50 MHz (13C NMR).
Chemical shifts are reported in parts per million (ppm); 1H
and 13C chemical shifts are referenced to the proton resonance
due to the residual protons in the deuteriated NMR solvent.
Microanalyses were carried out by Atlantic Microlab, Inc.,
Norcross, GA.
1
1261, 1178, 1117, 1033 cm-1; H NMR (CDCl3/CD3CN, 5:1) δ
4.93 (q, 2H, J H-F ) 10 Hz), 3.9 (br s, 1H, OH). Anal. Calcd
for C3H3IF6O4S: C, 9.58; H, 0.80; I, 33.75. Found: C, 9.49;
H, 0.79; I, 33.69.
All commercial reagents were ACS reagent grade and used
without further purification. 1-[Bis(trifluoroacetoxy)iodo]-
(11) Ha¨bich, D.; Effenberger, F. Synthesis 1979, 841.

Stable, Fluoroalkyl Analogs of Koser’s Reagent
J . Org. Chem., Vol. 61, No. 23, 1996 8275
1-[Hydr oxy[(tr iflu or om eth an esu lfon yl)oxy]iodo]-1H,1H-
p er flu or op r op a n e (3f). According to the above typical
procedure, 1-[bis(trifluoroacetoxy)iodo]-1H,1H-perfluoropropane-
(2b) (0.559 g, 1.15 mmol) was reacted with 0.3 mL (1.5 mmol)
of trimethylsilyl triflate to afford 0.452 g (92%) of 3f as a white,
waxy solid: mp 105-109 °C dec; IR (KBr) 3444, 2956, 1261,
IR (KBr) 3028, 2959, 2837, 1584, 1485, 1286, 1259, 1247, 1177,
1
1129, 1033, 995, 830, 811, 765 cm-1; H NMR (CDCl3) δ 7.99
(d, 2H, J ) 8 Hz), 6.98 (d, 2H, J ) 8 Hz), 4.65 (q, 2H, J ) 10
Hz), 3.89 (s, 3H). Anal. Calcd for C10H9F6IO4S: C, 25.77; H,
1.95; I, 27.22. Found: C, 25.69; H, 2.00; I, 27.31.
(1H ,1H -P er flu or op r op yl)[4-(t r im et h ylsilyl)p h en yl]-
iod on iu m Tr ifla te (7g). According to the above typical
procedure, 3f (0.200 g, 0.47 mmol) was reacted with 1,4-bis-
(trimethylsilyl)benzene (0.116 g, 0.52 mmol) at 0 °C to give
7g as a white microcrystalline solid: yield 0.197 g (75%); mp
130-132 °C dec; IR (CCl4) 3023, 2952, 1328, 1268, 1248, 1212,
1178, 1117, 1033 cm-1 1H NMR (CDCl3/CD3CN, 5:1) δ 6.02
;
(br s, 1H, OH), 4.93 (t, 2H, J H-F ) 10 Hz). Anal. Calcd for
C4H3IF8O4S: C, 11.28; H, 0.71; I, 29.79. Found: C, 11.12; H,
0.70; I, 29.38.
Rea ction s of 1-[Hyd r oxy(tosyloxy)iod o]-1H,1H-p er flu -
or oeth a n e (3a ) w ith Silyl En ol Eth er s a n d Cycloh exen e:
Typ ica l P r oced u r e. To a stirred mixture of tosylate 3a
(0.300 g, 0.76 mmol) in methylene chloride (20 mL) was added
1-phenyl-1-[(trimethylsilyl)oxy]ethylene (0.17 mL, 0.78 mmol)
dropwise at room temperature. The mixture was stirred for
1 h until a clear solution formed. The solvent was then
evaporated, and the crude product was recrystallized from
ether-hexane to give (tosyloxy)acetophenone (4) as a white
microcrystalline solid: yield 0.127 g (58%); mp 92-94 °C (lit.7
mp 91-92 °C).
Similarly, reaction of tosylate 3a (0.2 g, 0.5 mmol) in
methylene chloride (20 mL) with (1-cyclohexenyloxy)trimeth-
ylsilane (0.11 mL, 0.55 mmol) was carried out at 0 °C to give
R-(tosyloxy)cyclohexanone (5) as a white microcrystalline
solid: yield 0.075 g (56%); mp 73-75 °C (lit.7 mp 74-76 °C).
Under similar conditions, reaction of tosylate 3a (0.300 g, 0.76
mmol) with cyclohexene (0.1 mL, 1.0 mmol) at 0 °C afforded
cis-1,2-bis(tosyloxy)cyclohexane 6: yield 0.094 g (65%); mp
115-118 °C (lit.8 mp 115-117 °C, R-form).
(1H,1H-P er flu or oeth yl)[4-(tr im eth ylsilyl)p h en yl]iod o-
n iu m Tr ifla te (7b): Typ ica l P r oced u r e. To a stirred
mixture of 1-[hydroxy[(trifluoromethanesulfonyl)oxy]iodo]-
1H,1H-perfluoroethane (3c) (0.200 g, 0.53 mmol) in methylene
chloride (20 mL) was added 1,4-bis(trimethylsilyl)benzene
(0.130 g, 0.6 mmol) in portions at -20 °C. The mixture was
warmed to room temperature and allowed to stir for 1-2 h
until a clear solution formed. The solvent was then evapo-
rated, and the crude product 7b was recrystallized from ether-
hexane to give a white microcrystalline solid. The solid was
filtered and dried in vacuo: yield 0.191 g (62%); mp 88-90
°C; IR (KBr) 3060, 2951, 2889, 1566, 1371, 1248, 1172, 1034,
1001, 840, 801, 749, 706, 650, 645, 578, 516, 479 cm-1; 1H NMR
(CDCl3) δ 8.15 (d, 2H, J ) 8 Hz), 7.69 (d, 2H, J ) 8 Hz), 4.75
(q, 2H, J ) 10 Hz), 0.29 (s, 9H). Anal. Calcd for C12H15F6-
IO3SSi: C, 28.36; H, 2.97; I, 24.97. Found: C, 27.99; H, 2.93;
I, 24.88.
(1H,1H-P er flu or oeth yl)(2-m eth ylp h en yl)iod on iu m Tr i-
fla te (7c). According to the above typical procedure, 3c (0.200
g, 0.53 mmol) was reacted with 2-(trimethylsilyl)toluene (0.12
mL, 0.58 mmol) to give 7c as a white microcrystalline solid:
yield 0.171 g (72%); mp 75-77 °C dec; IR (KBr) 3044, 2970,
1383, 1267, 1177, 1130, 1066, 1035, 1008, 745, 645, 576, 518
cm-1; 1H NMR (CDCl3) δ 8.12 (d, 1H, J ) 8 Hz), 7.56 (m, 2H),
7.24 (t, 1H, J ) 8 Hz), 4.57 (q, 2H, J ) 10 Hz), 2.62 (s, 3H);
13C NMR (CDCl3) δ 141.4, 139.0, 129.8, 128.1, 127.4, 120.9 (q,
J ) 278 Hz), 118.4 (q, J ) 320 Hz), 101.1, 68.5 (q, J ) 39 Hz),
28.0. Anal. Calcd for C10H9F6IO3S: C, 26.68; H, 2.02; I, 28.19.
Found: C, 26.57; H, 2.04; I, 28.28.
1
1172, 1045, 1010, 853, 843, 803, 752, 707, 651, 515 cm-1; H
NMR (CDCl3 δ 8.17 (d, 2H, J ) 8 Hz), 7.62 (d, 2H, J ) 8 Hz),
4.70 (t, 2H, J ) 10 Hz), 0.29 (s, 9H). Anal. Calcd for
C13H15F8IO3SSi: C, 27.97; H, 2.71; I, 22.73. Found: C, 27.85;
H, 2.69; I, 22.87.
(1H ,1H -P er flu or op r op yl)(2-m et h ylp h en yl)iod on iu m
Tr ifla te (7h ). According to the above typical procedure, 3f
(0.200 g, 0.47 mmol) was reacted with 2-(trimethylsilyl)toluene
(0.10 mL, 0.52 mmol) at 0 °C to give 7h as a white microcrys-
talline solid: yield 0.176 g (75%); mp 106-108 °C dec; IR (KBr)
3023, 2952, 1335, 1270, 1245, 1230, 1211, 1195, 1171, 1034,
1012, 795, 707, 650 cm-1; 1H NMR (CDCl3/CD3CN, 10:1) δ 8.17
(d, 1H, J ) 8 Hz), 7.56 (m, 2H), 7.24 (t, 1H, J ) 8 Hz), 4.62 (t,
2H, J ) 10 Hz), 2.68 (s, 3H). Anal. Calcd for C11H9F8IO3S:
C, 26.42; H, 1.81; I, 25.37. Found: C, 26.53; H, 1.85; I, 25.46.
(1H ,1H -P er flu or op r op yl)(4-m et h ylp h en yl)iod on iu m
Tr ifla te (7i). According to the above typical procedure, 3f
(0.200 g, 0.47 mmol) was reacted with 4-(trimethylsilyl)toluene
(0.10 mL, 0.52 mmol) at 0 °C to give 7i as a white microcrys-
talline solid: yield 0.152 g (65%); mp 124-126 °C dec; IR (KBr)
3043, 2952, 1333, 1268, 1248, 1235, 1212, 1197, 1172, 1035,
1010, 798, 707, 646 cm-1; 1H NMR (CDCl3) δ 7.96 (d, 2H, J )
8 Hz), 7.32 (d, 2H, J ) 8 Hz), 4.67 (t, 2H, J ) 10 Hz), 2.45 (s,
3H). Anal. Calcd for C11H9F8IO3S: C, 26.42; H, 1.81; I, 25.37.
Found: C, 26.30; H, 1.85; I, 25.44.
(1H ,1H -P e r flu o r o p r o p y l)(4-m e t h o x y p h e n y l)io d o -
n iu m Tr ifla te (7j). According to the above typical procedure,
3f (0.200 g, 0.47 mmol) was reacted with 2-(trimethylsilyl)-
toluene (0.10 mL, 0.52 mmol) at 0 °C to give 7j as a white,
microcrystalline solid, which was filtered directly out of the
reaction mixture: yield 0.179 g (74%); mp 147-148 °C dec;
IR (CCl4) 3098, 3010, 2951, 2833, 1572, 1488, 1459, 1439, 1405,
1331, 1306, 1267, 1238, 1223, 1164, 1056, 1046, 1012, 638, 574,
1
515 cm-1; H NMR (CDCl3) δ 8.00 (d, 2H, J ) 8 Hz), 7.04 (d,
2H, J ) 8 Hz), 4.70 (t, 2H, J ) 10 Hz), 3.91 (s, 3H); 13C NMR
(CDCl3/CF3CO2H, 10:1) δ 164.8, 139.4, 120.9 (q, J ) 278 Hz),
119.0, 118.4 (q, J ) 320 Hz), 93.9, 56.0, 35.7 (q, J ) 39 Hz),
20.3. Anal. Calcd for C11H9F8IO4S: C, 25.60; H, 1.76; I, 24.59.
Found: C, 25.48; H, 1.79; I, 24.70.
(1H ,1H -P e r flu o r o e t h y l)[(t r im e t h y ls ily l)e t h y n y l]-
iod on iu m Tr ifla te (8b): Typ ica l P r oced u r e. To a stirred
mixture of 1-[hydroxy[(trifluoromethanesulfonyl)oxy]iodo]-
1H,1H-perfluoroethane (3c) (0.200 g, 0.53 mmol) in methylene
chloride (20 mL) was added bis(trimethylsilyl)acetylene (0.14
mL, 0.6 mmol) in portions at -10 °C. The mixture was
warmed to room temperature and allowed to stir for 1-2 h
until a clear solution formed. The solvent was then evapo-
rated, and the crude product 8b was recrystallized from
dichloromethane-hexane to give a white microcrystalline
solid. The solid was filtered and dried in vacuo: yield 0.169 g
(70%); mp 54-57 °C dec; IR (CCl4): 2966, 2900, 2100, 1560,
(1H,1H-P er flu or oeth yl)(4-m eth ylph en yl)iodon iu m Tr i-
fla te (7d ). According to the above typical procedure, 3c (0.200
g, 0.53 mmol) was reacted with 4-(trimethylsilyl)toluene (0.12
mL, 0.58 mmol) to give 7d as a white microcrystalline solid:
yield 0.185 g (78%); mp 76-80 °C dec; IR (KBr) 3031, 2955,
1481, 1381, 1262, 1177, 1115, 1034, 1001, 797, 645, 578, 517,
1
1414, 1250, 1004, 857, 840, 699, 623 cm-1; H NMR (CDCl3):
δ 4.72 (q, 2H), 0.19 (s, 9H); 13C NMR (CDCl3) δ 120.7 (q, J )
278 Hz), 118.6 (q, J ) 320 Hz), 104.1, 68.4 (q, J ) 39 Hz),
20.2, -0.2.
1
474 cm-1; H NMR (CDCl3) δ 7.96 (d, 2H, J ) 8 Hz), 7.32 (d,
2H, J ) 8 Hz), 4.67 (q, 2H, J ) 10 Hz), 2.45 (s, 3H); 13C NMR
(CDCl3/CD3CN, 10:1) δ 137.1, 136.7, 130.8, 120.9 (q, J ) 278
Hz), 118.4 (q, J ) 320 Hz), 89.4, 68.5 (q, J ) 39 Hz), 20.3.
Anal. Calcd for C10H9F6IO3S: C, 26.68; H, 2.02. Found: C,
27.04; H, 2.08.
(1H ,1H -P e r flu or oe t h yl)(3,3-d im e t h ylb u t yn yl)iod o-
n iu m Tr ifla te (8a ). According to the above typical procedure,
3c (0.200 g, 0.53 mmol) was reacted with 1-(trimethylsilyl)-
3,3-dimethylbutyne (0.15 mL, 0.6 mmol) to give 8a as a white
microcrystalline solid: yield 0.165 g (74%); mp 70-72 °C dec;
IR (CCl4) 3034, 2976, 2937, 2908, 2869, 2180, 2151, 1455, 1401,
1367, 1285, 1217, 1173, 1135, 1062, 1023, 834, 635, 577, 514
cm-1; 1H NMR (CDCl3) δ 4.72 (q, 2H, J ) 10 Hz), 1.23 (s, 9H);
13C NMR (CDCl3) δ 120.9 (q, J ) 278 Hz), 118.7 (q, J ) 320
Hz), 102.9, 68.4 (q, J ) 39 Hz), 30.8, 29.8, -8.3.
(1H ,1H -P er flu or oet h yl)(4-m et h oxyp h en yl)iod on iu m
Tr ifla te (7e). According to the above typical procedure, 3c
(0.200 g, 0.53 mmol) was reacted with 4-(trimethylsilyl)anisole
(0.15 mL, 0.59 mmol) at -40 °C to give 7e as a white
microcrystalline solid: yield 0.190 g (77%); mp 92-94 °C dec;

8276 J . Org. Chem., Vol. 61, No. 23, 1996
Zhdankin et al.
(1H,1H-P er flu or oeth yl)(p h en yleth yn yl)iod on iu m Tr i-
fla te (8c). According to the above typical procedure, 3c (0.200
g, 0.53 mmol) was reacted with 1-phenyl-2-(trimethylsilyl)-
ethyne (0.15 mL, 0.6 mmol) to give 8c as a white microcrys-
talline solid: yield 0.155 g (65%); mp 66-68 °C dec; IR (CCl4)
3067, 3028, 2158, 1490, 1438, 1419, 1237, 1213, 1136, 1064,
g, 0.47 mmol) was reacted with 1-phenyl-2-(trimethylsilyl)-
ethyne (0.11 mL, 0.56 mmol) to give 8f as a white microcrys-
talline solid: yield 0.165 g (74%); mp 102-104 °C dec; IR (CCl4)
3040, 2970, 2162, 1405, 1329, 1286, 1229, 1213, 1192, 1174,
1055, 1015, 793, 784, 757, 713, 683, 630 cm-1; 1H NMR (CDCl3)
δ 7.4 (m, 5H), 4.85 (t, 2H, J ) 10 Hz); 13C NMR (CDCl3/CD3-
CN, 10:1) δ 131.9, 128.4, 128.0, 123.0, 121-105 (a group of
multiplets), 118.7 (q, J ) 320 Hz), 93.9, 67.8 (t, J ) 39 Hz),
6.9.
1
1021, 959, 854, 686, 596, 519 cm-1; H NMR (CDCl3) δ 7.42
(m, 2H), 7.31 (m, 3H), 4.72 (q, 2H, J ) 10 Hz); 13C NMR
(CDCl3/CD3CN, 10:1) δ 131.9, 128.5, 128.0, 123.0, 120.9 (q, J
) 278 Hz), 118.7 (q, J ) 320 Hz), 93.6, 68.3 (q, J ) 39 Hz),
6.6.
Ack n ow led gm en t. This work was supported by a
research grant from the National Science Foundation
(NSF/CHE-9505868).
(1H ,1H -P er flu or op r op yl)(3,3-d im et h ylb u t yn yl)iod o-
n iu m Tr ifla te (8d ). According to the above typical procedure,
3f (0.200 g, 0.47 mmol) was reacted with 1-(trimethylsilyl)-
3,3-dimethylbutyne (0.10 mL, 0.56 mmol) to give 8d as a white
microcrystalline solid: yield 0.174 g (76%); mp 122-124 °C
dec; IR (CCl4) 3027, 2968, 2939, 2909, 2870, 2180, 2151, 1406,
1
Su p p or tin g In for m a tion Ava ila ble: Copies of H NMR
for compounds 8a ,b,d and copies of 13C NMR for 8a ,c,e (6
pages). This material is contained in libraries on microfiche,
immediately follows this article in the microfilm version of the
journal, and can be ordered from the ACS; see any current
masthead page for ordering information.
1332, 1283, 1219, 1180, 1057, 1017, 707, 633, 574, 515 cm-1
;
1H NMR (CDCl3/CD3CN, 10:1) δ 4.73 (t, 2H, J ) 10 Hz), 1.30
(s, 9H).
(1H,1H-P er flu or opr opyl)(ph en yleth yn yl)iodon iu m Tr i-
fla te (8e). According to the above typical procedure, 3f (0.200
J O961336N