Biphenyl- and terphenyl-based recyclable organic trivalent iodine reagents

Article abstract of DOI:10.1016/j.tet.2006.09.112

Biphenyl- and terphenyl-based recyclable trivalent iodine reagents, such as 4-bromo-4′-(diacetoxyiodo)biphenyl, 4,4′-bis(diacetoxyiodo)biphenyl, 1,4-bis[4-(diacetoxyiodo)phenyl]benzene, 4-bromo-4′-[(hydroxy)(tosyloxy)iodo]biphenyl, 4,4′-bis[(hydroxy)(tosyloxy)iodo]biphenyl, were simply prepared and their reactivities for the oxidative rearrangement of ketones to esters, TEMPO-mediated oxidation of alcohols to aldehydes or ketones, oxidative dealkylation of N-alkylsulfonamides to sulfonamides, and α-tosyloxylation of ketones were compared with p-(diacetoxyiodo)toluene and p-[(hydroxy)(tosyloxy)iodo]toluene to show the same reactivities and, moreover, the biphenyl- and terphenyl-based iodoarenes formed were recovered by simple filtration of the reaction mixture in every reaction. Thus, these biphenyl- and terphenyl-based trivalent iodine reagents can be used as the recyclable reagents.

Full text of DOI:10.1016/j.tet.2006.09.112

Tetrahedron 62 (2006) 12408–12414
Biphenyl- and terphenyl-based recyclable organic
trivalent iodine reagents
Atsushi Morodab and Hideo Togoa,b,
*
aGraduate School of Science and Technology, Faculty of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
bDepartment of Chemistry, Faculty of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
Received 30 August 2006; accepted 27 September 2006
Available online 2 November 2006
Abstract—Biphenyl- and terphenyl-based recyclable trivalent iodine reagents, such as 4-bromo-40-(diacetoxyiodo)biphenyl, 4,40-bis(diace-
toxyiodo)biphenyl, 1,4-bis[4-(diacetoxyiodo)phenyl]benzene, 4-bromo-40-[(hydroxy)(tosyloxy)iodo]biphenyl, 4,40-bis[(hydroxy)(tosyloxy)-
iodo]biphenyl, were simply prepared and their reactivities for the oxidative rearrangement of ketones to esters, TEMPO-mediated oxidation of
alcohols to aldehydes or ketones, oxidative dealkylation of N-alkylsulfonamides to sulfonamides, and a-tosyloxylation of ketones were com-
pared with p-(diacetoxyiodo)toluene and p-[(hydroxy)(tosyloxy)iodo]toluene to show the same reactivities and, moreover, the biphenyl- and
terphenyl-based iodoarenes formed were recovered by simple filtration of the reaction mixture in every reaction. Thus, these biphenyl- and
terphenyl-based trivalent iodine reagents can be used as the recyclable reagents.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
sometimes lowers the reactivities than those observed with
DIB and HTIB. Recently, Kita et al. reported an elegant
approach for recyclable trivalent iodine reagents, such
as 1,3,5,7-tetrakis[(diacetoxyiodo)phenyl]adamantane4a and
tetrakis[4-(diacetoxyiodo)phenyl]methane.4b Thus, these
are not polymers, but they are recyclable trivalent iodine
reagents. This approach impressed us, since we have experi-
enced some limitations with polymer-supported trivalent
iodine reagents, for example, oxidative dealkylation of
N-alkylsulfonamides with PSDIB does not proceed effec-
tively. Here, as a part of our study on environmentally benign
organic synthesis with hypervalent iodines, we would like to
report biphenyl- and terphenyl-based recyclable trivalent
iodine reagents.
Recently, synthetic use of hypervalent iodines for organic
synthesis has been investigated widely because of their
efficient oxidizing ability and less toxicity.1 Especially,
(diacetoxyiodo)benzene (DIB), iodosylbenzene, and
[(hydroxy)(tosyloxy)iodo]benzene (HTIB) are well-known
reagents and the oxidative reactions can be carried out under
mild conditions with easy handling, high chemoselectivity,
and low toxicity.2 Based on the broad synthetic utility of
these organohypervalent iodine compounds for organic syn-
thesis, previously, we and others reported polymer-supported
hypervalent iodine reagents such as poly[4-(diacetoxy)-
iodo]styrene (PSDIB), poly[4-(hydroxy)(tosyloxy)iodo]-
styrene (PSHTIB), etc.3 The major advantages of the use
of these polymer-supported hypervalent iodine reagents are
as follows: reactions can be monitored by standard methods
such as TLC, GC, HPLC, etc., reaction products can be
obtained by simple filtration to remove the polymer-
supported reagent, and regeneration and reuse of the
recovered polymer-supported reagents are possible. Thus,
polymer-supported hypervalent iodines are environmentally
friendly reagents, and have wide applicability to organic
synthesis in the chemical and pharmaceutical industries.
However, the introduction of high loading rate of organic
trivalent iodine groups onto polystyrene is not so easy and
2. Results and discussion
Our approach is focused on biphenyl- and terphenyl-based
trivalent iodines,5 since the diiodination of biphenyl and ter-
phenyl is easy and the solubility of these iodo compounds is
not so high. Thus, the solubility of 4-bromo-40-iodobiphenyl,
4,40-diiodobiphenyl, and 1,4-bis(p-iodophenyl)benzene in
hexane is 8.4 mg/ml, 2.2 mg/ml, and slightly soluble,
respectively, and even in chloroform it is 114.9 mg/ml,
32.3 mg/ml, and 0.9 mg/ml, respectively. So, it is expected
that 4,40-diiodobiphenyl and 1,4-bis(p-iodophenyl)benzene
are the core candidates in recyclable hypervalent iodines.
The iodination of 4-bromobiphenyl, biphenyl, and terphenyl
proceeded smoothly with molecular iodine and iodine pent-
oxide in nitrobenzene in the presence of a small amount of
carbon tetrachloride and sulfuric acid, as in the preparation
of PSDIB from polystyrene, as shown in Scheme 1. For
Keywords: 4-Bromo-40-(diacetoxyiodo)biphenyl; 4,40-Bis(diacetoxyiodo)-
biphenyl; 1,4-Bis[4-(diacetoxyiodo)phenyl]benzene; 4-Bromo-40-[(hydroxy)-
(tosyloxy)iodo]biphenyl; 4,40-Bis[(hydroxy)(tosyloxy)iodo]biphenyl; Oxidation;
Aldehyde; Ketone; Ester; a-Tosyloxyketone; Sulfonamide.
* Corresponding author. Fax: +81 43 290 2874; e-mail: togo@faculty.
chiba-u.jp
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.09.112

A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
12409
OAc
I
Br
NaBO3
OAc
A-i
98%
AcOH, 45 °C
I2, I2O5
Br
Br
I
PhNO2, CCl4
mCPBA
CHCl3, r.t.
p-TsOH•H2O
H2SO4, 100 °C
67%
OH
I
Br
OTs
A-ii
89%
OAc
I
OAc
I
NaBO3
OAc
OAc
B-i 98%
AcOH, 45 °C
I2, I2O5
I
I
PhNO2, CCl4
H2SO4,
90 °C~100 °C
mCPBA
p-TsOH•H2O
HO
60%
OH
I
CHCl3, r.t.
I
TsO
OTs
85%
B-ii
I2, I2O5
mCPBA
CHCl3, AcOH, r.t.
I
I
PhNO2, CCl4
H2SO4, 100 °C
76%
mCPBA
CHCl3, r.t.
p-TsOH•H2O
OH
I
OH
I
AcO
I
OAc
I
p-TsOH•H2O
CH3CN, r.t.
OTs
OTs
AcO
OAc
C-ii
98%
C-i
Scheme 1. Preparation of biphenyl- and terphenyl-based trivalent iodines.
the preparation of 4-bromo-40-(diacetoxyiodo)biphenyl (A-i),
4,40-bis(diacetoxyiodo)biphenyl (B-i),6 and 1,4-bis[4-(di-
acetoxyiodo)phenyl]benzene (C-i), there are two methods.
The first method is the oxidation of iodo compounds with
sodium peroxoborate in acetic acid as a standard method,7
and the second one is the oxidation with mCPBA in a mixture
of chloroform and acetic acid as shown in Scheme 1.4
4-Bromo-40-[(hydroxy)(tosyloxy)iodo]biphenyl (A-ii) and
4,40-bis[(hydroxy)(tosyloxy)iodo]biphenyl (B-ii) were di-
rectly prepared with mCPBA and p-toluenesulfonic acid
monohydrate in chloroform, based on our previous report.8
1,4-Bis[4-(hydroxy)(tosyloxy)iodophenyl]benzene (C-ii)
could not be prepared cleanly by the direct preparation of
1,4-bis(p-iodophenyl)benzene with mCPBA and p-toluene-
sulfonic acid monohydrate or by the exchange reac-
tion of 1,4-bis[4-(diacetoxyiodo)phenyl]benzene (C-i) with
p-toluenesulfonic acid monohydrate, as a traditional method.
Table 1. Oxidative 1,2-aryl migration of alkyl aryl ketones to esters with
reagents A-i–D-i
Reagent
(1.2 eq. or 0.6 eq.)a
(CH3O)3CH / H+
60 °C
O
C
CH3
Ar
C2H5
Ar
Ar
C
H
CO2CH3
Reagent
Time (h)
Yields (%)
Product
Recoveryb
A-i
B-i
C-i
D-i
91
85
88
88
81
84
94
(—)
2
A-i
B-i
C-i
D-i
88
85
88
92
90
84
96
(—)
2
H3C
H3CO
F
A-i
B-i
C-i
D-i
89
91
88
92
80
80
90
(—)
2.1. Oxidative 1,2-aryl migration of alkyl aryl ketones
3
1,2-Aryl migration of propiophenones with the present triva-
lent iodine reagentsA-i, B-i, and C-i in trimethyl orthoformate
was carried out effectively, based on the previous report,9 and
the reactivities were compared with that of standard p-(diace-
toxyiodo)toluene (D-i) as shown in Table 1. Since biphenyl-
and terphenyl-based reagents B-i and C-i have two trivalent
iodine groups, the mole amount used is reduced to a half-
millimole amount of trivalent iodine reagents A-i and D-i.
Thus, the results indicate that the present trivalent iodine
A-i
B-i
C-i
D-i
86
84
87
82
81
84
94
(—)
5c
a
For B-i and C-i: 0.6 equiv, and for A-i and D-i: 1.2 equiv.
Yield of 4,40-diiodobiphenyl, 4-bromo-40-iodobiphenyl, or 1,4-bis(p-
iodophenyl)benzene.
b
c
Reaction was carried out at room temperature.

12410
A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
reagents A-i, B-i, and C-i showed the same reactivity to give
the rearranged esters in high yields, as with the standard
reagent D-i. Here, 4-bromo-40-iodobiphenyl, 4,40-diiodobi-
phenyl, and 1,4-bis(p-iodophenyl)benzene formed as byprod-
ucts could be recovered in high yields by simple filtration of
the reaction mixture, though p-iodotoluene could not be
recovered at all. Generally, the collecting ability is slightly
decreased in the order of 1,4-bis(p-iodophenyl)benzene,
4,40-diiodobiphenyl,and4-bromo-40-iodobiphenyl.Thus,after
the reaction with 1,4-bis[4-(diacetoxyiodo)phenyl]benzene
(C-i), 1,4-bis(p-iodophenyl)benzenewas recovered quantita-
tively by simple filtration.
and ketone in good yields, and the reactivities were com-
pared again with standard p-(diacetoxyiodo)toluene (D-i)
as shown in Table 2. In trivalent iodine reagents B-i and
C-i, a half-millimole amount of the reagents was used, based
on that of trivalent iodine reagents A-i and D-i, and
10 mol % of TEMPO was used for effective oxidation.
Again, the results indicate that trivalent iodine reagents A-i,
B-i, and C-i showed the same reactivity as with the standard
reagent D-i. Here, 4-bromo-40-iodobiphenyl, 4,40-diiodo-
biphenyl, and 1,4-bis(p-iodophenyl)benzene formed as
byproducts could be recovered in high yields by simple
filtration of the reaction mixture, though p-iodotoluene could
not be recovered at all. TEMPO-mediated oxidation of
cinnamyl alcohol with regenerated C-i provided cinnamal-
dehyde in high yields, together with high recovery of 1,4-
bis(p-iodophenyl)benzene.
2.2. TEMPO-mediated oxidation of alcohols
to aldehydes or ketones
TEMPO-mediated oxidation of primary alcohols and sec-
ondary alcohols10 with the present trivalent iodine reagents
A-i, B-i, and C-i in chloroform proceeded smoothly at
room temperature to provide the corresponding aldehydes
2.3. Sonochemical dealkylation of N-alkylsulfonamides
Previously, we reported sonochemical oxidative dealkylation
of N-alkylsulfonamides with DIB in the presence of iodine to
form the corresponding free sulfonamides and aldehydes.11
Based on the report, N-alkylsulfonamides were treated with
the present trivalent iodine reagents A-i, B-i, and C-i in the
presence of iodine in 1,2-dichloroethane under ultrasonic
irradiation conditions to generate the corresponding free
sulfonamides in good yields as shown in Table 3. Again,
the results indicate that trivalent iodine reagents A-i, B-i,
and C-i have the same reactivity as that of standard reagent
D-i. 4-Bromo-40-iodobiphenyl, 4,40-diiodobiphenyl, and
1,4-bis(p-iodophenyl)benzene formed as byproducts could
be recovered in high yields by simple filtration of the reaction
mixture, though p-iodotoluene could not be recovered at all.
Table 2. TEMPO-mediated oxidation of alcohols to aldehydes or ketone
with reagents A-i–D-i
Reagent (1.2 eq. or 0.6 eq.)a
R1
R1 CH2OH
or
CHO
or
TEMPO (0.1 eq.)
CHCl3, r.t.
R2
R3
R2
CH OH
R3
C O
Reagent
Product
Time (h)
Yields (%)
Product
Recoveryb
A-i
B-i
C-i
D-i
98
93
99
97
93
89
96
(—)
CHO
2
2
2
2.4. a-Tosyloxylation of ketones
A-i
B-i
C-i
D-i
93
90
90
94
75
89
96
(—)
CHO
a-Tosyloxyketones are a very important strategic precursor
for the direct construction of various heterocyclic
A-i
B-i
C-i
71
73
86
83
Table 3. Sonochemical dealkylation of N-alkyl-sulfonamides with reagents
A-i–D-i
CHO
95
94
97c
97d
99
93c
95d
(—)
Reagent (3.0 eq. or 1.5 eq.)a
I2 (1.0 eq.)
R
SO2NHR'
R
R SO2NH2
D-i
ClCH2CH2Cl, 30 ~ 40 °C
3 h
A-i
B-i
C-i
D-i
81
79
79
89
84
90
92
(—)
CHO
CHO
2
24
16
24
Reagent
R'
Yields (%)
Product
Recoveryb
A-i
B-i
C-i
D-i
95
95
97
93
89
95
(—)
A-i
B-i
C-i
D-i
77
80
76
71
92
94
98
(—)
CH2CH3
100
A-i
B-i
C-i
D-i
65
65
66
91
96
88
92
(—)
A-i
B-i
C-i
D-i
87
100
89
92
94
99
(—)
CH3(CH2)10–CHO
Ph
97
A-i
B-i
C-i
D-i
100
97
100
99
80
86
94
(—)
A-ic
B-ic
C-ic
D-ic
66
66
58
64
90
98
98
(—)
CH3
O
CH2CH3
Br
a
For B-i and C-i: 0.6 equiv, and for A-i and D-i: 1.2 equiv.
a
b
Yield of 4,40-diiodobiphenyl, 4-bromo-40-iodobiphenyl, or 1,4-bis(p-
iodophenyl)benzene.
Yield with the first regenerated C-i.
For B-i and C-i: 1.5 equiv, and for A-i and D-i: 3.0 equiv.
b
c
Yield of 4,40-diiodobiphenyl, 4-bromo-40-iodobiphenyl, or 1,4-bis(p-
iodophenyl)benzene.
Reaction was carried out for 6 h.
c
d
Yield with the second regenerated C-i.

A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
12411
compounds such as thiazoles, oxazoles, selenazoles, imid-
3. Conclusion
azoles, pyrazoles, benzofurans, and lactones; and HTIB
and PSHTIB are the sole reagents for the direct preparation
of a-tosyloxyketones from ketones2c,12 or alcohols.13 Since
biphenyl-based reagent B-ii has two trivalent iodine groups,
a half-millimole amount of the reagent was used based on
that of trivalent iodine reagents A-ii and D-ii. Here, various
ketones were treated with the present trivalent iodine
reagents A-ii and B-ii under refluxing conditions in aceto-
nitrile to provide the corresponding a-tosyloxyketones in
good yields as shown in Table 4. Again, the results indicate
that the trivalent iodine reagents A-ii and B-ii have the same
reactivity as that of the standard reagent D-ii. 4-Bromo-40-
iodobiphenyl and 4,40-diiodobiphenyl formed as byproducts
could be recovered in high yields by simple filtration of the
reaction mixture, though p-iodotoluene could not be recov-
ered at all.
4-Bromo-40-(diacetoxyiodo)biphenyl (A-i), 4,40-bis(di-
acetoxyiodo)biphenyl (B-i), and 1,4-bis[4-(diacetoxyiodo)-
phenyl]benzene (C-i) could be used for the oxidative
rearrangement of ketones to the esters, TEMPO-mediated
oxidation of alcohols to the corresponding aldehydes or
ketones, and oxidative dealkylation of N-alkylsulfonamides
to sulfonamides, and 4-bromo-40-[(hydroxy)(tosyloxy)-
iodo]biphenyl (A-ii) and 4,40-bis[(hydroxy)(tosyloxy)iodo]-
biphenyl (B-ii) could be used for the a-tosyloxylation of
ketones. These trivalent iodine reagents showed the same
reactivity as that of p-(diacetoxyiodo)toluene (D-i) and
p-[(hydroxy)(tosyloxy)iodo]toluene (D-ii). Moreover, after
the reactions, the formed iodoarenes are recovered in high
yields by simple filtration of the reaction mixture and they
can be regenerated and reused for the same reaction. Thus,
the present trivalent iodine reagents can be used as simple
recyclable reagents, instead of polymer-supported trivalent
iodine reagents such as PSDIB or PSHTIB.
Table 4. a-Tosyloxylation of ketones with reagents A-ii, B-ii, and D-ii
Reagent
(1.2 eq. or 0.6 eq.)a
CH3CN, reflux
4. Experimental
4.1. General
O
O
R'
OTs
R'
R
R
1H and 13C NMR spectra were obtained with JEOL-JNM-
LA-400, JEOL-JNM-LA-400s, and JEOL-JNM-LA-500
spectrometers. Chemical shifts are expressed in parts per
million downfield from tetramethylsilane (TMS) in d units.
Mass spectra were recorded on JEOL-HX-110 and JEOL-
JMS-ATII15 spectrometers. Melting points were determined
on Yamato melting points apparatus Model MP-21. Silica
gel 60 (Kanto Kagaku Co.) was used for column chromato-
graphy and Wakogel B-5F was used for preparative TLC.
Sonication was performed by Tokyo Rika Kikai AC-70
CO (200 W; 28 kHz) ultrasonic cleaning device.
Reagent
Product
Time (h)
Yields (%)
Product Recoveryb
O
A-ii
B-ii
D-ii
85
85
87
88
88
(—)
4
OTs
O
A-ii
B-ii
D-ii
81
84
91
93
81
(—)
8
8
OTs
CH3
O
A-ii
B-ii
D-ii
92
87
95
84
81
(—)
4.2. Typical procedure for the preparation of iodoarenes
OTs
OTs
Cl
O
A mixture of 5.2 g of biphenyl, 12.4 g of iodine, 4.7 g of
diiodine pentoxide, 10 ml of carbon tetrachloride, and 15 ml
of 50% sulfuric acid in 20 ml of nitrobenzene was kept at
90w100 ꢀC for 48 h. After the reaction, the reaction mixture
was poured into methanol (350 ml). The precipitates were
collected by filtration (8.1 g, 60% yield).
A-ii
B-ii
D-ii
79
88
87
78
81
(—)
8
4
4
O2N
O
A-ii
B-ii
D-ii
81
84
91
93
81
(—)
CH3
OTs
4.2.1. 4-Bromo-40-iodobiphenyl. Mp 166–168 ꢀC; IR
O
A-ii
B-ii
D-ii
82
86
85
83
74
(—)
CH3
OTs
(KBr) 1470, 1380, 1000, 800 cmꢁ1 1H NMR (CDCl3)
;
d¼7.29 (2H, d, J¼8.5 Hz), 7.41 (2H, d, J¼8.5 Hz), 7.56
(2H, d, J¼8.5 Hz), 7.76 (2H, d, J¼8.5 Hz); 13C NMR
(CDCl3) d¼93.43 (q), 121.99 (q), 128.44 (t), 128.72 (t),
132.02 (t), 137.99 (t), 138.96 (q), 139.49 (q).
CH3
O
A-ii
B-ii
D-ii
81
79
80
81
84
(—)
C7H15
8
8
4
OTs
4.2.2. 4,40-Diiodobiphenyl. Mp 200–201 ꢀC; IR (KBr)
2360, 1470, 1380, 1000, 800, 460 cmꢁ1; 1H NMR (CDCl3)
d¼7.28 (4H, d, J¼8.5 Hz), 7.76 (4H, d, J¼8.5 Hz); 13C
NMR (CDCl3) d¼93.49 (q), 128.67 (t), 137.99 (t), 139.54
(q); elemental analysis calcd for C12H8I2: C 35.50, H 1.99,
I 62.51%; found: C 35.58, H 2.03, I 62.56%.
O
A-iic
B-iic
D-iic
77
72
65
87
82
(—)
C4H9
CH3
C4H9
OTs
O
O
A-ii
B-ii
D-ii
90
83
70
91
84
(—)
CH3
OTs
4.2.3. 4,40-Bis(p-iodophenyl)benzene. Mp >280 ꢀC; IR
a
For B-ii: 0.6 equiv and for A-ii and D-ii: 1.2 equiv.
Yield of 4,40-diiodobiphenyl and 4-bromo-40-iodobiphenyl.
Reaction was carried out at 60 ꢀC.
1
(KBr) 2600, 1480, 1400, 1000, 800, 460 cmꢁ1; H NMR
b
c
(CDCl3) d¼7.37 (4H, d, J¼8.5 Hz), 7.63 (4H, s), 7.79

12412
A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
(4H, d, J¼8.5 Hz); elemental analysis calcd for C18H12I2: C
chloroform (60 ml) was added mCPBA (2.10 g, 11 mmol).
The obtained mixture was stirred for 4 h at room temperature
under an argon atmosphere. After the reaction, diethyl ether
(20 ml) was added to the reaction mixture, and the obtained
mixture was filtered and the solids were washed with diethyl
ether to provide 4,40-bis[(hydroxy)(tosyloxy)iodo]biphenyl
(3.32 g, 85% yield).
44.84, H 2.51, I 52.65%; found: C 44.25, H 2.61, I 52.55%.
4.3. Typical procedure for the preparation
of (diacetoxyiodo)arenes
A mixture of 4,40-diiodobiphenyl (1.02 g, 2.5 mmol) and
sodium peroxoborate tetrahydrate (3.85 g, 25 mmol) in
AcOH (150 ml) was kept at 40–50 ꢀC for 1 h, and then
sodium peroxoborate tetrahydrate (3.85 g, 25 mmol) was
added again. The mixture was stirred for 24 h at 40–50 ꢀC.
After the reaction, water was added and the mixture was
extracted with chloroform three times. The organic layer was
dried over sodium sulfate. After filtration, removal of the
solvent under reduced pressure gave 4,40-bis(diacetoxy-
iodo)biphenyl (1.60 g, 99% yield).
4.5.1. 4-Bromo-40-[(hydroxy)(tosyloxy)iodo]biphenyl.
Mp (decomp.) 98–100 ꢀC; IR (KBr) 3700–3200, 1480,
1
1390, 1190, 1130, 1040, 1000, 800, 600 cmꢁ1; H NMR
(CDCl3+3 drops of CF3CO2H) d¼2.45 (3H, s), 7.35 (2H,
d, J¼8.2 Hz), 7.48 (2H, d, J¼8.7 Hz), 7.66 (2H, d, J¼
8.7 Hz), 7.73 (2H, d, J¼8.2 Hz), 7.77 (2H, d, J¼8.7 Hz),
8.29 (2H, d, J¼8.7 Hz); elemental analysis calcd for
C19H16BrIO4S: C 41.70, H 2.95%; found: C 41.54, H 3.06%.
4.3.1. 4-Bromo-40-(diacetoxyiodo)biphenyl. Mp (de-
4.5.2. 4,40-Bis[(hydroxy)(tosyloxy)iodo]biphenyl. Mp
comp.) 171 ꢀC; IR (KBr) 2400–2300, 1560, 1410, 1000,
(decomp.) 104 ꢀC; IR (KBr) 3700–3200, 1470, 1190, 1130,
1
800 cmꢁ1; H NMR (CDCl3) d¼2.03 (6H, s), 7.45 (2H, d,
1040, 800, 600 cmꢁ1 1H NMR (CDCl3+3 drops of
;
J¼8.5 Hz), 7.62 (2H, d, J¼8.5 Hz), 7.65 (2H, d, J¼
8.5 Hz), 8.15 (2H, d, J¼8.5 Hz); 13C NMR (CDCl3) d¼
20.52 (p), 120.54 (q), 123.23 (q), 128.99 (t), 129.49 (t),
132.39 (t), 135.68 (t), 138.15 (q), 143.84 (q), 176.61 (q);
elemental analysis calcd for C16H14BrIO4: C 40.28, H
2.96%; found: C 40.25, H 3.06%.
CF3CO2H) d¼2.45 (6H, s), 7.33 (4H, d, J¼8.2 Hz), 7.72
(4H, d, J¼8.2 Hz), 7.81 (4H, d, J¼8.7 Hz), 8.37 (4H, d, J¼
8.7 Hz); elemental analysis calcd for C26H24I2O8S2$H2O: C
39.01, H 3.27%; found: C 39.31, H 3.16%.
4.6. Typical procedure for the conversion of arylketones
to esters
4.3.2. 4,40-Bis(diacetoxyiodo)biphenyl. Mp(decomp.)176–
1
177 ꢀC; IR (KBr) 2360, 1580, 1410, 1000, 800 cmꢁ1; H
Sulfuric acid (2 mmol) was added dropwise to a solution of
4,40-bis(diacetoxyiodo)biphenyl (0.6 mmol) and propiophe-
none (1.0 mmol) in 3 ml of trimethyl orthoformate at 0 ꢀC.
The reaction mixture was stirred for 2 h at 60 ꢀC under an
argon atmosphere. Hexane was then added to the solution,
and the formed 4,40-diiodobiphenyl was removed by filtra-
tion. The filtrate was poured into water (10 ml), extracted
with ether, and dried over Na2SO4. The solvent was evapo-
rated under reduced pressure and the residue was poured
into methanol (5 ml). Once again 4,40-diiodobiphenyl was
removed by filtration. The filtrate was evaporated under
reduced pressure and the residue was purified by preparative
TLC on silica gel (85% yield).
NMR (CDCl3) d¼2.04 (12H, s), 7.67 (4H, d, J¼8.5 Hz),
8.20 (4H, d, J¼8.5 Hz); 13C NMR (CDCl3) d¼20.52 (p),
121.42 (q), 129.89 (t), 135.76 (t), 142.90 (q), 176.65 (q);
elemental analysis calcd for C20H20I2O8$H2O: C 36.39,
H 3.36, I 38.44%; found: C 36.32, H 3.27, I 38.49%.
4.4. Preparation of 1,4-bis(4-diacetoxyiodophenyl)-
benzene
To a stirred solution of 4,40-bis(p-iodophenyl)benzene
(0.96 g, 2 mmol) in a mixture of CHCl3 (300 ml) and
AcOH (40 ml) was added mCPBA (2.08 g, 12 mmol) at
room temperature. The reaction mixture was stirred for
24 h under the same reaction conditions. The resultant
slightly clouded solution was filtered to give a clear solution.
Chloroform of the filtrate was removed under reduced pres-
sure and then hexane was added to the residue and stirred for
8 h to precipitate 1,4-bis(4-diacetoxyiodophenyl)benzene.
After filtration, the crude product was washed with hexane
and Et2O several times, and dried in vacuo to give 1,4-
bis(4-diacetoxyiodophenyl)benzene (1.41 g, 98% yield).
4.6.1. Methyl 2-phenylpropanoate. Bp 65 ꢀC/2.5 mmHg
(lit.14 104–105 ꢀC/18 mmHg); IR (neat) 2980, 1740, 1600,
1
1495, 1455, 1210, 1170 cmꢁ1; H NMR (CDCl3) d¼1.50
(3H, d, J¼7.2 Hz), 3.66 (3H, s), 3.73 (1H, q, J¼7.2 Hz),
7.23–7.35 (5H, m).
4.6.2. Methyl 2-(4-methylphenyl)propanoate. IR (neat)
2955, 1740, 1515, 1460, 1205, 1165 cmꢁ1 1H NMR
;
(CDCl3) d¼1.48 (3H, d, J¼7.2 Hz), 2.33 (3H, s), 3.65
(3H, s), 3.69 (1H, q, J¼7.2 Hz), 7.13 (2H, d, J¼8.1 Hz),
7.19 (2H, d, J¼8.1 Hz).
4.4.1. 1,4-Bis(4-diacetoxyiodophenyl)benzene. Mp (de-
comp.) 214 ꢀC; IR (KBr) 2360, 1560, 1390, 1000,
1
800 cmꢁ1; H NMR (CDCl3) d¼2.04 (12H, s), 7.71 (4H,
s), 7.73 (4H, d, J¼8.5 Hz), 8.19 (4H, d, J¼8.5 Hz); elemen-
tal analysis calcd for C26H24I2O8$3CH3COOH: C 42.78, H
4.04, I 28.25%; found: C 42.67, H 4.24, I 28.30%.
4.6.3. Methyl 2-(4-methoxyphenyl)propanoate. IR (neat)
2980, 2960, 2840, 1740, 1340 cmꢁ1 1H NMR (CDCl3)
;
d¼1.47 (3H, d, J¼7.2 Hz), 3.65 (3H, s), 3.68 (1H, q,
J¼7.2 Hz), 3.79 (3H, s), 6.86 (2H, dt, J¼8.7 and 2.0 Hz),
7.22 (2H, dt, J¼8.7 and 2.0 Hz).
4.5. Typical procedure for the preparation of
[hydroxy(tosyloxy)iodo]arenes
4.6.4. Methyl 2-(4-fluorophenyl)propanoate. IR (neat)
1
To a mixture of 4,40-diiodobiphenyl (2.03 g, 5 mmol) and
p-toluenesulfonic acid monohydrate (2.00 g, 11 mmol) in
2980, 2960, 1740, 1320 cmꢁ1; H NMR (CDCl3) d¼1.48
(3H, d, J¼7.2 Hz), 3.66 (3H, s), 3.71 (1H, q, J¼7.2 Hz),

A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
12413
7.00 (2H, tt, J¼8.7 and 2.1 Hz), 7.26 (2H, ddt, J¼8.7, 5.3,
argon atmosphere, and then the reaction mixture was poured
into methanol (5 ml). The mixture was filtered to remove
4,40-diiodobiphenyl. After removal of the solvent under
reduced pressure, the residue was poured into methanol
(5 ml). The mixture was filtered to remove the formed
4,40-diiodobiphenyl. After removal of the solvent under
reduced pressure, the residue was chromatographed on silica
gel by column chromatography.
and 2.1 Hz).
4.7. Typical procedure for the oxidation of alcohols
to aldehydes or ketones
4,40-Bis(diacetoxyiodo)biphenyl (0.3 mmol) was added to
a solution of cinnamyl alcohol (0.5 mmol) and TEMPO
(7.8 mg, 0.05 mmol) in CHCl3 (1 ml), and the mixture was
stirred at room temperature for 2 h. Then, hexane was added
and the mixture was filtered to remove the formed 4,40-di-
iodobiphenyl. After removal of the solvent from the filtrate,
the residue was poured into methanol (5 ml). Once again
4,40-diiodobiphenyl was removed by filtration. After re-
moval of the solvent from the filtrate, the corresponding
carbonyl compound was obtained.
4.9.1. a-Tosyloxyacetophenone. Mp 90 ꢀC (lit.13c 90–
91 ꢀC); IR (KBr) 1715, 1360, 1180 cmꢁ1; 1H NMR (CDCl3)
d¼2.45 (3H, s), 5.27 (2H, s), 7.35 (2H, d, J¼8.5 Hz), 7.47
(2H, t, J¼8.2 Hz), 7.61 (1H, t, J¼8.2 Hz), 7.85 (4H, m).
4.9.2. a-Tosyloxy-p-methylacetophenone. Mp 80 ꢀC
1
(lit.13c 82–83 ꢀC); IR (KBr) 1700, 1350, 1170 cmꢁ1; H
NMR (CDCl3) d¼2.41 (3H, s), 2.45 (3H, s), 5.24 (2H, s),
7.26 (2H, d, J¼8.1 Hz), 7.35 (2H, d, J¼8.2 Hz), 7.74 (2H,
d, J¼8.1 Hz), 7.86 (2H, d, J¼8.2 Hz).
All aldehydes and ketones mentioned in this work are com-
mercially available, and all compounds were identified with
the authentic samples.
4.9.3. a-Tosyloxy-p-chloroacetophenone. Mp 122 ꢀC
4.8. Typical procedure for the oxidative dealkylation
of N-alkylsulfonamides
(lit.13c 125 ꢀC); IR (KBr) 1710, 1360, 1190 cmꢁ1 1H
;
NMR (CDCl3) d¼2.46 (3H, s), 5.21 (3H, s), 7.35 (2H, d,
J¼8.4 Hz), 7.45 (2H, d, J¼8.6 Hz), 7.80 (2H, d, J¼
8.6 Hz), 7.84 (2H, d, J¼8.4 Hz).
4,40-Bis(diacetoxyiodo)biphenyl (0.75 mmol) and iodine
(0.5 mmol) were added to a solution of N-ethyl-benzylsulfo-
namide (0.5 mmol) in 1,2-dichloroethane (7 ml). The
mixture was stirred preliminarily for 10 min under dark
conditions, and then irradiated with an ultrasonic cleaning
bath (200 W; 28 kHz or 100 W; 28, 45, and 100 kHz) for
3 h under an argon atmosphere in the range of 30–40 ꢀC.
After the reaction, the mixture was poured into ethyl acetate
and washed with aq sodium sulfite (Na2SO3) solution and
subsequently washed with water. The organic layer was
dried over sodium sulfate (Na2SO4). After removal of the
solvent under reduced pressure, the residue was poured
into methanol (5 ml). The mixture was filtered to remove
the formed 4,40-diiodobiphenyl. After removal of the solvent
under reduced pressure, the residue was chromatographed
on silica gel preparative TLC using a mixture of hexane
and ethyl acetate (2:1) as an eluant.
4.9.4. a-Tosyloxy-p-nitroacetophenone. Mp 139–ꢁ1140 ꢀC
(lit.13c 139 ꢀC); IR (KBr) 1710, 1340, 1180 cm
;
1H
NMR (CDCl3) d¼2.47 (3H, s), 5.25 (2H, s), 7.37 (2H, d,
J¼8.3 Hz), 7.83 (2H, d, J¼8.3 Hz), 8.02–8.05 (2H, m),
8.31–8.35 (2H, m).
4.9.5. a-Tosyloxypropiophenone. Mp 68 ꢀC (lit.13c 68–
69 ꢀC); IR (KBr) 1700, 1370, 1170, 830, 760, 660 cmꢁ1
;
1H NMR (CDCl3) d¼1.60 (3H, d, J¼7.0 Hz), 2.41 (3H, s),
5.79 (1H, q, J¼7.0 Hz), 7.29 (2H, d, J¼8.1 Hz), 7.46 (2H,
t, J¼7.2 Hz), 7.60 (1H, t, J¼7.2 Hz), 7.75 (2H, d, J¼
7.2 Hz), 7.88 (2H, d, J¼8.1 Hz).
4.9.6. a-Tosyloxy-p-methylpropiophenone. Mp 88–89 ꢀC;
1
IR (KBr) 1690, 1360, 1180, 920 cmꢁ1; H NMR (CDCl3)
d¼1.56 (3H, d, J¼7.0 Hz), 2.41 (3H, s), 2.42 (3H, s), 5.77
(1H, q, J¼7.0 Hz), 7.23 (4H, m), 7.73 (4H, m); 13C NMR
(CDCl3) d¼18.78 (p), 21.63 (p), 21.72 (p), 77.32 (t),
127.92 (t), 128.86 (t), 129.44 (t), 129.72 (t), 131.14 (q),
133.53 (q), 144.89 (q), 144.93 (q), 194.29 (q); HRMS
(FAB) obsd: M+H¼319.1004, calcd for C10H12O:
M+H¼319.1007.
4.8.1. Benzylsulfonamide. Mp 99–100 ꢀC (lit.15 101–
102 ꢀC); IR (KBr) 3380, 3320, 1325, 1125 cmꢁ1; 1H NMR
(CDCl3) d¼4.30 (2H, s), 4.72 (2H, br s), 7.37–7.44 (5H,
m); MS (EI) found: M+¼171.
4.8.2. 5-Bromo-2-methylbenzenesulfonamide. Mp 163.0–
164.5 ꢀC (lit.16 164.0–165.0 ꢀC); IR (KBr) 3400, 3295,
1
1295, 1160 cmꢁ1; H NMR (CDCl3) d¼2.63 (3H, s), 4.92
4.9.7. a-Tosyloxyoctyl phenyl ketone. Mp 59–60 ꢀC; IR
1
(2H, br s), 7.21 (1H, d, J¼8.0 Hz), 7.58 (1H, dd, J¼8.2
and 2.2 Hz), 8.15 (1H, d, J¼2.2 Hz); MS (EI) found: M+¼
249, 251.
(KBr) 1700, 1340, 1180 cmꢁ1; H NMR (CDCl3) d¼0.86
(3H, t, J¼7.0 Hz), 1.20–1.43 (10H, m), 1.84–1.91 (2H, m),
2.40 (3H, s), 5.59 (1H, dd, J¼8.2 and 4.8 Hz), 7.24 (2H, d,
J¼8.0 Hz), 7.43–7.47 (2H, m), 7.56–7.60 (1H, m), 7.73–
7.77 (2H, m), 7.84–7.86 (2H, m); 13C NMR (CDCl3)
d¼14.01 (p), 21.60 (p), 22.53 (s), 24.95 (s), 28.74 (s),
28.87 (s), 31.58 (s), 32.66 (s), 81.37 (t), 128.00 (t), 128.61
(t), 128.69 (t), 133.12 (q), 133.72 (t), 133.98 (q), 144.92
(q), 1955.02 (q); elemental analysis calcd for C22H28O4S:
C 68.01, H 7.43%; found: C 68.01, H 7.26%.
Benzenesulfonamide was identified with commercially
available authentic compound.
4.9. Typical procedure for the a-tosyloxylation of
ketones
4,40-Bis[(hydroxy)(tosyloxy)iodo]biphenyl (0.3 mmol) was
added to a solution of acetophenone (0.5 mmol) in aceto-
nitrile (3 ml). The mixture was refluxed for 4 h under an
4.9.8. a-Tosyloxy-6-undecanone. Mp 72 ꢀC; 1H NMR
(CDCl3) d¼0.70–0.80 (3H, m), 0.86–0.89 (3H, m),

12414
A. Moroda, H. Togo / Tetrahedron 62 (2006) 12408–12414
552; (g) Chen, J.; Huang, X. Synthesis 2004, 1577; (h) Chen,
J.; Huang, X. Synthesis 2004, 2459; (i) Marinescu, L. G.;
Pedersen, C. M.; Bols, M. Tetrahedron 2005, 61, 123; (j)
Teduka, T.; Togo, H. Synlett 2005, 923; (k) Chung, W.; Kim,
D.; Lee, Y. Synlett 2005, 2175; (l) But, T. Y. S.; Tashino, Y.;
Togo, H.; Toy, P. H. Org. Biomol. Chem. 2005, 3, 970; (m)
Herrerias, C. I.; Zhang, T. Y.; Li, C. Tetrahedron Lett. 2006,
47, 13; (n) Ladziata, U.; Willging, J.; Zhdankin, V. V. Org.
Lett. 2006, 8, 167.
1.09–1.75 (14H, m), 2.46 (3H, s), 2.49–2.53 (2H, m), 4.64
(1H, dd, J¼8.0 and 4.6 Hz), 7.36 (2H, d, J¼8.0 Hz), 7.79–
7.82 (2H, m); 13C NMR (CDCl3) d¼13.64 (p), 13.89 (p),
21.70 (p), 21.99 (s), 22.45 (s), 22.50 (s), 26.63 (s), 31.25
(s), 31.50 (s), 38.20 (s), 84.94 (t), 128.72 (t), 130.67 (t),
133.80 (q), 146.13 (q), 208.63 (q); elemental analysis calcd
for C18H28O4S: C 63.50, H 8.29% found: C 63.40, H 8.50%.
4.9.9. a-Tosyloxy-2,4-pentadione. Mainly enol tautomer;
mp 82 ꢀC (lit.13b 82–83 ꢀC); IR (KBr) 3060, 1600, 1370,
4. (a) Tohma, H.; Maruyama, A.; Maeda, A.; Maegawa, T.; Dohi,
T.; Shiro, M.; Morita, T.; Kita, Y. Angew. Chem., Int. Ed. 2004,
43, 3595; (b) Dohi, T.; Maruyama, A.; Yoshimura, M.;
Morimoto, K.; Tohma, H.; Shiro, M.; Kita, Y. Chem.
Commun. 2005, 2205.
1
1200, 1180, 800 cmꢁ1; H NMR (CDCl3) d¼1.96 (6H, s),
2.49 (3H, s), 7.40 (2H, d, J¼8.1 Hz), 7.83 (2H, d,
J¼8.1 Hz), 14.80 (1H, s).
5. Recently, synthetic use of 4,40-bis(dichloroiodo)biphenyl as
a recyclable reagent was reported, see: Yusubov, M. S.;
Drygunova, L. A.; Zhdankin, V. V. Synthesis 2004, 2289.
6. Stapp, P. R. U.S. Patent 422,1927, 1980.
7. McKillop, A.; Kemp, D. Tetrahedron 1989, 45, 3299.
8. Yamamoto, Y.; Togo, H. Synlett 2005, 2486.
Acknowledgements
Financial support by a Grant-in-Aid for Scientific Research
(No. 16655012) from the Ministry of Education, Science,
Sports, and Culture of Japan is gratefully acknowledged.
9. Togo, H.; Abe, S.; Nogami, G.; Yokoyama, M. Bull. Chem. Soc.
Jpn. 1999, 72, 2351.
References and notes
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J. Chem. Soc., Perkin Trans. 1 1992, 707; (n) Varma, R. S.;
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1999, 64, 2883; (p) Lee, J. C.; Choi, J.-H. Synlett 2001, 234;
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Sakuratani, K.; Togo, H. ARKIVOC 2003, 11.
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2, 92; (b) Moriarty, R. M.; Vaid, R. K. Synthesis 1990, 431;
(c) Moriarty, R. M.; Vaid, R. K.; Koser, G. F. Synlett 1990,
365; (d) Stang, P. J. Angew. Chem., Int. Ed. Engl. 1992, 31,
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Tetrahedron 1997, 53, 1179; (l) Zhdankin, V. V. Rev.
Heteroatom Chem. 1997, 17, 133; (m) Muraki, T.; Togo, H.;
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Kitamura, T.; Fujiwara, Y. Org. Prep. Proced. Int. 1997, 29,
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Kyokaishi 2000, 58, 1048; (u) Togo, H.; Katohgi, M. Synlett
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Synthesis 2004, 2673; (f) Chen, J.; Huang, X. Synlett 2004,
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Haruta, J. Synthesis 1984, 231.
15. Graham, S. L.; Scholz, T. H. Synthesis 1986, 1031.
16. Huntress, E. H.; Carten, F. H. J. Am. Chem. Soc. 1940, 62, 511.