Novel preparation of polymer-supported iodobenzene and its synthetic utility as a recyclable reagent with m-chloroperbenzoic acid

Article abstract of DOI:10.1055/s-0029-1218795

Three novel polymer-supported iodobenzene compounds A₀, A ₆, and A₁₀ were prepared from the reaction of commercially available cross-linked poly(p-chloromethyl)styrene with m-iodobenzylalcohol, 6-(m-iodobenzyloxy)-1-hexanol, and 10-(m-iodobenzyloxy)-1-decanol. Their catalytic reactivity and reusability for the oxidative α-tosyloxylation of ketones and the cyclization of N-methoxy-2-arylethanesulfonamides in the presence of m-chloroperbenzoic acid (mCPBA) were confirmed to provide -tosyloxyketones and N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides, respectively, in good yields. Georg Thieme Verlag Stuttgart · New York.

Full text of DOI:10.1055/s-0029-1218795

PAPER
2355
Novel Preparation of Polymer-Supported Iodobenzene and Its Synthetic
Utility as a Recyclable Reagent with m-Chloroperbenzoic Acid
P
olymer-Supporte
u
d Iodobenzen
h
e
suku Suzuki, Hideo Togo*
Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
Fax +81(43)2902792; E-mail: togo@faculty.chiba-u.jp
Received 4 March 2010; revised 2 April 2010
would like to report the polymer-supported iodobenzene-
catalyzed a-tosyloxylation of ketones and the cyclization
of N-methoxy-2-arylethanesulfonamides to N-methoxy-
3,4-dihydro-2,1-benzothiazine-2,2-dioxides.
Abstract: Three novel polymer-supported iodobenzene com-
pounds A0, A6, and A10 were prepared from the reaction of commer-
cially available cross-linked poly(p-chloromethyl)styrene with m-
iodobenzylalcohol, 6-(m-iodobenzyloxy)-1-hexanol, and 10-(m-io-
dobenzyloxy)-1-decanol. Their catalytic reactivity and reusability
for the oxidative a-tosyloxylation of ketones and the cyclization of
N-methoxy-2-arylethanesulfonamides in the presence of m-chlo-
roperbenzoic acid (mCPBA) were confirmed to provide a-tosyloxy-
ketones and N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides,
respectively, in good yields.
First, m-iodobenzylalcohol was selected as the iodoaryl
group for the polymer-supported iodobenzene, because
m-iodobenzylalcohol could be efficiently prepared by the
reduction of methyl m-iodobenzoate with diisobutylalu-
minum hydride (DIBAL-H). Methyl m-iodobenzoate was
quantitatively obtained from commercially available m-
iodobenzoic acid. Then, three novel polymer-supported
iodobenzene compounds A0, A6, and A10 were prepared
by the reactions of commercially available cross-linked
poly(p-chloromethyl)styrene (loading rate: 1.87 mmol/g)
with m-iodobenzylalcohol, 6-(m-iodobenzyloxy)-1-hex-
anol, and 10-(m-iodobenzyloxy)-1-decanol, respectively,
as shown in Scheme 1. The loading rates of the iodoben-
zene group in the three polymer-supported materials A0
(1.26 mmol/g), A6 (1.09 mmol/g), and A10 (0.99 mmol/g)
were estimated from both the recovery of m-iodobenzyl-
alcohol, 6-(m-iodobenzyloxy)-1-hexanol, and 10-(m-io-
dobenzyloxy)-1-decanol from the reactions with cross-
linked poly(p-chloromethyl)styrene, respectively, and by
the elemental analysis of A0, A6, and A10. Peaks assign-
able to the iodobenzene groups in A0, A6, and A10 were
Key words: polymer-supported PhI, recycle mCPBA, a-tosyloxy-
ketone, ketone, N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-di-
oxide, catalyst
Many synthetic studies of hypervalent iodines have been
undertaken.1 Among them, [(hydroxy)(tosyloxy)io-
do]benzene is highly efficient and is, so far, the sole re-
agent capable of direct a-tosyloxylation of ketones.2a,b a-
Tosyloxyketones are very important strategic precursors
for the preparation of various heteroaromatics, such as thi-
azoles, imidazoles, oxazoles, selenazoles, pyrazoles, and
benzofurans.2 Therefore, we have been studying the
synthetic uses of [(hydroxy)(tosyloxy)iodo]arenes, 1-
(arenesulfonyloxy)benziodoxolones, and poly[4-(hy-
droxy)(tosyloxy)iodo]styrenes for the construction of thi-
azoles, imidazoles, imidazo[1.2-a]pyridines, and 2,1-
benzothiazines.3 On the other hand, the aromatic iodide-
catalyzed oxidative conversions of substrates such as ke-
tones, hydroquinones, and alcohols with m-chloroperben-
zoic acid (mCPBA) or Oxone® has become very popular4
because it is a metal-free oxidative reaction and is thus
environmentally benign. Recently, we also reported an ef-
ficient method to prepare various [(hydroxy)(sulfonyl-
oxy)iodo]arenes directly from iodoarenes with mCPBA
and sulfonic acids at room temperature.5 Such methods in-
clude the iodobenzene-catalyzed and the ion-supported
iodobenzene-catalyzed a-tosyloxylation of ketones with
mCPBA and p-toluenesulfonic acid monohydrate, and the
iodobenzene-catalyzed and the ion-supported iodoben-
zene-catalyzed preparation of 3,4-dihydro-1H-2,1-benzo-
thiazine 2,2-dioxides from N-methoxy-2-arylethane-
sulfonamides with mCPBA.6 Here, as part of our study on
the catalytic use of iodoarenes for organic synthesis,6 we
1
readily observed by H NMR measurement in CDCl3. In
particular, peaks of the iodobenzene group of A6 and A10
were clearly observed. This indicates that the iodobenzene
groups in A0, A6, and A10 are flexible and freely soluble in
organic solvents. This observation suggests that A0, A6,
1. NaH (1.3 equiv)
DMF, 0 °C, 1 h
HOCH2
PS
CH2OCH2
2.
PS
CH2Cl, 3 d
I
I
A0: loading rate 1.26 mmol/g
1. NaH (1.3 equiv), DMF,
0 °C, 1 h
I
O
nOH
PS
2.
CH2Cl, 60 °C, 3 d
O
I
n O
PS
A
A
6 (n = 6): loading rate 1.09 mmol/g
10 (n = 10): loading rate 0.99 mmol/g
SYNTHESIS 2010, No. 14, pp 2355–2360
Advanced online publication: 20.05.2010
x
x.
x
x
.
2
0
1
0
DOI: 10.1055/s-0029-1218795; Art ID: F04110SS
© Georg Thieme Verlag Stuttgart · New York
Scheme 1 Preparation of polymer-supported iodobenzene

2356
Y. Suzuki, H. Togo
PAPER
and A10 may not only have reactivities that are comparable moderate yields. The advantages of using these polymer-
to iodobenzene, but should also be reusable, unlike vola- supported iodobenzene compounds are easy isolation of
tile iodobenzene.
the products by filtration and their reusability in the same
reactions.
Entry 1 in Table 1 shows the effect of A0, A6, and A10 on
the yield of a-tosyloxyacetophenone in the reaction of
acetophenone with mCPBA and p-toluenesulfonic acid
monohydrate in chloroform or acetonitrile at 50 °C. As
shown in entries 1, 7, and 8, A6 and A10 showed better re-
activity than A0. Propiophenone, m-nitroacetophenone, 3-
pentanone, 6-undecanone, ethyl benzoylacetate, and meth-
yl acetoacetate were treated with mCPBA and p-toluene-
sulfonic acid monohydrate in the presence of A6 and A10
to provide the corresponding a-tosyloxyketones in good
to moderate yields under the same conditions (entries 9–
14). After the reaction, A6 and A10 were recovered quanti-
tatively and could be reused for the same a-tosyloxylation
of p-nitroacetophenone, maintaining good to moderate
yields of the product (entries 2–5). The reason why the
yields of a-tosyloxy-p-nitroacetophenone from p-nitroace-
tophenone decreased using polymer-supported material
A6 and A10 that was recovered after the second and third
run, was that the iodobenzene groups of A6 and A10 were
partly oxidized to inert PhI(V) groups by mCPBA. Practi-
cally, the yield of a-tosyloxy-p-nitroacetophenone from
p-nitroacetophenone could be markedly increased when
the PhI(V) groups of polymer-supported material A10 re-
covered after the third run were reduced to PhI(I) groups
by treatment with NaBH4, before the reaction with p-ni-
troacetophenone, mCPBA, and p-toluenesulfonic acid
(entry 6). The advantages of using polymer-supported io-
dobenzene are the simple isolation of a-tosyloxyketones
by filtration, and the reusability of the polymer-supported
material. Thus, when the filtrate from the reaction mixture
was poured into chloroform and washed with aqueous so-
dium bicarbonate, a-tosyloxylketones were obtained in
high purity (>90%) after removal of the solvent. The cy-
clization of N-methoxy-2-phenylethanesulfonamide with
A0, A6, and A10, in the presence of mCPBA, was carried
out to provide N-methoxy-3,4-dihydro-2,1-benzothia-
zine-2,2-dioxide in good yields, as shown in Table 2 (en-
tries 1–4). Although the reactivities of A0, A6, and A10
were the same, the polymer-supported material could be
recovered quantitatively and reused for the same reaction,
maintaining good yields of the product. The same treat-
ment of other N-methoxy-2-arylethanesulfonamides with
A0, A6 and A10 in the presence of mCPBA provided the
corresponding 7-substituted N-methoxy-3,4-dihydro-2,1-
benzothiazine-2,2-dioxides in good to moderate yields,
depending on the substrates (entries 5–8).
Table 1 a-Tosyloxylation of Ketones with mCPBA and
p-TsOH·H2O in the Presence of A0, A6, or A10
O
A0, A6, or A10, mCPBA,
p-TsOH⋅H2O
O
R2
OTs
R2
R1
R1
solvent, time, 50 °C
Ar-I
A0
A6
A10
(0.5 equiv)
(1.3 equiv)
(0.5 equiv)
1.1
2.5
5.0
2.5
mCPBA
p-TsOH⋅H2O
1.1
3.0
time
16 h
9 h
9 h
solvent
CHCl3
MeCN
MeCN
Entry
1
Product
Yields (%)
A0
A6
A10
O
OTs
28
71
85
2
3
4
5
6
–
–
–
–
–
77
77a
69b
64c
–
88
O
80a
73b
51c
86d
OTs
O2N
O
OTs
7
30
72
85
Cl
O
OTs
8
9
29
–
64
81
77
70
83
86
O
OTs
O
O2N
OTs
10
–
OTs
11
12
–
–
46
54
68e
77e
O
OTs
In conclusion, various a-tosyloxyketones were prepared
in good yields from the reaction of ketones with mCPBA
and p-toluenesulfonic acid monohydrate in the presence
of polymer-supported iodobenzene compounds A0, A6,
and A10, especially the latter two. The cyclization of N-
methoxy-2-arylethanesulfonamides with A0, A6, and A10
in the presence of mCPBA and p-toluenesulfonic acid
monohydrate occurred efficiently to provide N-methoxy-
3,4-dihydro-2,1-benzothiazine-2,2-dioxides in good to
O
O
O
13
–
70f
75f
OEt
OTs
Synthesis 2010, No. 14, 2355–2360 © Thieme Stuttgart · New York

PAPER
Polymer-Supported Iodobenzene
2357
1H and 13C NMR spectra were obtained with Jeol JNM-GSX-400,
Jeol JNM-LA-400, and Jeol JNM-LA-500 spectrometers. Chemical
shifts (d) are expressed in ppm downfield from TMS. Mass spectra
were recorded with Jeol HX-110 or Jeol JMS-ATII15 spectrome-
ters. IR spectra were measured with a Jasco FT/IR-4100 spectrom-
eter. Melting points were determined with a Yamato melting point
apparatus model MP-21. Silica gel 60 (Kanto Kagaku Co.) was used
for column chromatography and Wakogel B-5F was used for pre-
parative TLC. Cross-linked poly(p-chloromethyl)styrene (loading
rate: 1.87 mmol/g) was obtained from Argonaut Technologies Co.
Table 1 a-Tosyloxylation of Ketones with mCPBA and
p-TsOH·H2O in the Presence of A0, A6, or A10 (continued)
O
A0, A6, or A10, mCPBA,
p-TsOH⋅H2O
O
R2
OTs
R2
R1
R1
solvent, time, 50 °C
Ar-I
A0
A6
A10
(0.5 equiv)
(1.3 equiv)
(0.5 equiv)
1.1
2.5
5.0
2.5
mCPBA
p-TsOH⋅H2O
1.1
3.0
6-(m-Iodobenzyloxy)-1-hexanol and 10-(m-Iodobenzyloxy)-1-
decanol; Typical Procedure
time
16 h
9 h
9 h
solvent
CHCl3
MeCN
MeCN
A solution of 6-(2¢-tetrahydropyranyloxy)-1-hexanol (50 mmol,
10.11 g) in THF (25 mL) was stirred for 1 h with Na2SO4. After re-
moval of Na2SO4 from the solution, NaH (1.3 equiv, 55% purity, 65
mmol, 2.83 g) was added at 0 °C and the obtained mixture was
stirred for 2 h under an argon atmosphere. Then, m-iodobenzyl bro-
mide (1.1 equiv, 55 mmol, 16.27 g) was added and the mixture was
stirred at r.t. for 12 h. After the reaction, the mixture was quenched
with H2O (30 mL) and poured into Et2O (50 mL). The organic layer
was dried over Na2SO4. After filtration and removal of the solvent
under reduced pressure, MeOH (100 mL) and p-TsOH·H2O (0.4
equiv, 3.80 g) were added and the obtained mixture was stirred at
r.t. for 3 h. After the reaction and removal of the solvent under re-
duced pressure, 6-(m-iodobenzyloxy)-1-hexanol was obtained in a
crude state. Pure 6-(m-iodobenzyloxy)-1-hexanol was obtained in
95% yield by column chromatography on silica gel (EtOAc–
hexane, 1:2).
Entry
14
Product
Yields (%)
A0
A6
A10
O
O
–
70g
63g
OMe
OTs
a Yield with the first recovered polymer.
b Yield with the second recovered polymer.
c Yield with the third recovered polymer.
d Yield with the fourth recovered polymer, which was reduced by
NaBH4 in dioxane, before reuse.
e Reaction time was 1.5 h.
f Reaction time was 3 h.
g Reaction time was 1 h.
6-(m-Iodobenzyloxy)-1-hexanol
1H NMR (500 MHz, CDCl3): d = 1.34–1.44 (m, 4 H), 1.54–1.66 (m,
4 H), 3.46 (t, J = 6.5 Hz, 2 H), 3.62–3.68 (br s, 2 H), 4.44 (s, 2 H),
7.08 (t, J = 7.9, 7.6 Hz, 1 H), 7.29 (d, J = 7.6 Hz, 1 H), 7.61 (d,
J = 7.9 Hz, 1 H), 7.69 (s, 1 H).
Table 2 Cyclization of N-Methoxy-2-arylethanesulfonamides with
mCPBA in the Presence of A0, A6, or A10
A0, A6, or A10, mCPBA
(2.0 equiv)
10-(m-Iodobenzyloxy)-1-decanol
SO2
SO2NH
1H NMR (500 MHz, CDCl3): d = 1.25–1.39 (m, 12 H), 1.54–1.65
(m, 4 H), 3.46 (t, J = 6.5 Hz, 2 H), 3.61–3.67 (br s, 2 H), 4.42 (s,
2 H), 7.07 (t, J = 7.9, 7.6 Hz, 1 H), 7.29 (d, J = 7.6 Hz, 1 H), 7.60
(d, J = 7.9 Hz, 1 H), 7.70 (s, 1 H).
R
N
R
CF3CH2OH, r.t.
OMe
OMe
A0 (1.5 equiv), 16 h
6 (1.3 equiv), 9 h
10 (1.0 equiv), 6 h
A
A
Polymer-Supported PhI A0, A6, and A10; Typical Procedure
A solution of 6-(m-iodobenzyloxy)-1-hexanol (1.42 equiv, 61
mmol, 20.4 g) in DMF (20 mL) was stirred for 1 h with Na2SO4. Af-
ter removal of Na2SO4 from the solution, NaH (1.3 equiv, 80 mmol,
55% purity, 3.84 g) was added at 0 °C and the obtained mixture was
stirred for 2 h under an argon atmosphere. Then, cross-linked
poly(p-chloromethyl)styrene (loading rate: 1.87 mmol/g, 22.9 g)
was added and the obtained mixture was stirred for 3 d at 60 °C.
When the reaction was complete, H2O was added and the precipi-
tates were collected by filtration and washed with H2O and then
EtOH. The obtained solids were dried by vacuum pump to provide
polymer-supported PhI A6 in 91% yield. Unreacted 6-(m-iodoben-
zyloxy)-1-hexanol (7.38 g) was recovered by removal of the solvent
from the filtrate.
Entry
R
Yields
A0
75
–
A6
A10
75
1
2
3
4
5
6
7
8
H
H
H
H
74
79a
76b
82c
61
82a
85b
89c
65
–
–
CH2Cl
Me
–
51d
53
39
62
67
Polymer-Supported PhI A0
Br
39
38
1H NMR (500 MHz, CDCl3): d = 7.74 (s, 1 H), 7.63 (d, J = 8.0 Hz,
1 H), 7.33 (d, J = 7.6 Hz, 1 H), 7.10 (dd, J = 8.0, 7.6 Hz, 1 H), 4.66
(s, 2 H).
Cl
45
45
a Yield with the first recovered polymer.
b Yield with the second recovered polymer.
c Yield with the third recovered polymer.
d Reaction time was 24 h.
Anal. found: C, 75.55; H, 6.47; I, 16.01; loading rate: 1.26 mmol/g.
Polymer-Supported PhI A6
1H NMR (500 MHz, CDCl3): d = 7.69 (s, 1 H), 7.60 (d, J = 8.0 Hz,
1 H), 7.28 (d, J = 7.6 Hz, 1 H), 7.07 (dd, J = 8.0, 7.6 Hz, 1 H), 4.42
(s, 2 H), 3.52 (t, J = 6.6 Hz, 2 H), 3.45 (t, J = 6.6 Hz, 2 H).
Synthesis 2010, No. 14, 2355–2360 © Thieme Stuttgart · New York

2358
Y. Suzuki, H. Togo
PAPER
Anal. found: C, 77.28; H, 7.27; I, 11.62; loading rate: 1.09 mmol/g.
1H NMR (400 MHz, CDCl3): d = 1.03 (t, J = 7.3 Hz, 3 H), 1.35 (d,
J = 7.0 Hz, 3 H), 2.47 (s, 3 H), 2.60 (m, 2 H), 4.80 (q, J = 7.0 Hz,
1 H), 7.37 (d, J = 8.0 Hz, 2 H), 7.81 (d, J = 8.0 Hz, 2 H).
Polymer-Supported PhI A10
1H NMR (500 MHz, CDCl3): d = 7.69 (s, 1 H), 7.60 (d, J = 7.7 Hz,
1 H), 7.29 (d, J = 7.0 Hz, 1 H), 7.07 (dd, J = 7.7, 7.0 Hz, 1 H), 4.43
(s, 2 H), 3.52 (t, J = 6.7 Hz, 2 H), 3.45 (t, J = 6.4 Hz, 2 H).
a-Tosyloxy-6-undecanone
Mp 72 °C (Lit.3d 72 °C).
Anal. found: C, 78.91; H, 7.45; I, 9.41; loading rate: 0.99 mmol/g.
IR (neat): 1190, 1380, 1720 cm–1.
1H NMR (400 MHz, CDCl3): d = 0.70–0.80 (m, 3 H), 0.86–1.75 (m,
15 H), 2.46 (s, 3 H), 2.51 (t, J = 7.5 Hz, 2 H), 4.64 (dd, J = 8.0,
4.6 Hz, 1 H), 7.36 (d, J = 8.0 Hz, 2 H), 7.80 (d, J = 8.0 Hz, 2 H).
a-Tosyloxylation of Ketones; Typical Procedure
To a solution of acetophenone (120 mg, 1 mmol) in MeCN (5 mL)
were added polymer-supported PhI A10 (0.5 equiv, 444 mg), p-
TsOH·H2O (3.0 equiv, 570 mg), and mCPBA (65% purity, 2.5
equiv, 664 mg). The mixture was stirred for 9 h at 50 °C under an
argon atmosphere. After the reaction, MeOH (5 mL) was added and
the precipitated polymer-reagent was obtained by filtration and
washed with Et2O. The filtrate was poured into sat. aq NaHCO3 and
extracted with CHCl3 (3 × 15 mL). The organic layer was dried over
Na2SO4 and, after removal of the solvent under reduced pressure, a-
tosyloxyacetophenone was obtained in a crude state (purity >90%).
Pure a-tosyloxyacetophenone was obtained by short column chro-
matography on silica gel (EtOAc–hexane, 1:4) in 85% yield. Poly-
mer-supported iodobenzene was recovered in 87% yield (386 mg).
Methyl a-Tosyloxyacetoacetate
Oil.
IR (neat): 1180, 1320, 1720 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.30 (s, 3 H), 2.48 (s, 3 H), 3.71
(s, 3 H), 5.20 (s, 1 H), 7.38 (d, J = 8.5 Hz, 2 H), 7.83 (d, J = 8.5 Hz,
2 H).
13C NMR (100 MHz, CDCl3): d = 21.66, 26.53, 53.27, 80.34,
128.18, 129.98, 132.02, 145.90, 163.86, 196.98.
HRMS (FAB): m/z [M + 1] calcd for C12H15O6S: 287.0589; found:
287.0596.
a-Tosyloxyacetophenone
Mp 90 °C (Lit.2h 90–91 °C).
Ethyl a-Tosyloxybenzoylacetate
Oil.
IR (KBr): 1180, 1360, 1715 cm–1.
IR (neat): 1440, 1590, 1690 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.45 (s, 3 H), 5.27 (s, 2 H), 7.35
(d, J = 8.5 Hz, 2 H), 7.47 (t, J = 8.2 Hz, 2 H), 7.61 (t, J = 8.2 Hz,
1 H), 7.84 (d, J = 8.2 Hz, 2 H), 7.85 (d, J = 8.2 Hz, 2 H).
1H NMR (400 MHz, CDCl3): d = 1.18 (t, J = 7.0 Hz, 3 H), 2.85 (s,
3 H), 4.18 (m, 2 H), 5.59 (s, 1 H), 7.30 (d, J = 8.4 Hz, 2 H), 7.46 (t,
J = 7.5 Hz, 2 H), 7.61 (t, J = 7.5 Hz, 1 H), 7.79 (d, J = 8.5 Hz, 2 H),
7.93 (d, J = 8.5 Hz, 2 H).
13C NMR (100 MHz, CDCl3): d = 13.75, 21.63, 62.80, 78.03,
128.24, 128.71, 129.34, 129.82, 132.34, 133.28, 134.36, 145.68,
164.12, 188.19.
a-Tosyloxy-p-methylacetophenone
Mp 105 °C (Lit.7 82–83 °C).
IR (KBr): 1170, 1350, 1700 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.41 (s, 3 H), 2.45 (s, 3 H), 5.24
(s, 2 H), 7.26 (d, J = 8.1 Hz, 2 H), 7.35 (d, J = 8.2 Hz, 2 H), 7.74 (d,
J = 8.1 Hz, 2 H), 7.86 (d, J = 8.2 Hz, 2 H).
HRMS (FAB): m/z [M + 1] calcd for C18H19O6S: 363.0902; found:
363.0920.
a-Tosyloxy-m-nitroacetophenone
Mp 129–130 °C.
a-Tosyloxy-p-chloroacetophenone
Mp 123 °C (Lit.7 125 °C).
IR (KBr): 1615, 1375, 1348, 1188 cm–1.
IR (KBr): 1190, 1360, 1710 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.46 (s, 3 H), 5.25 (s, 2 H), 7.37
(d, J = 8.0 Hz, 2 H), 7.72 (t, J = 8.0 Hz, 1 H), 7.84 (d, J = 8.0 Hz,
2 H), 8.21 (dt, J = 8.0, 1.2 Hz, 1 H), 8.46 (dt, J = 8.0, 1.2 Hz, 1 H),
8.63 (t, J = 1.2 Hz, 1 H).
1H NMR (400 MHz, CDCl3): d = 2.46 (s, 3 H), 5.21 (s, 2 H), 7.35
(d, J = 8.4 Hz, 2 H), 7.45 (d, J = 8.6 Hz, 2 H), 7.80 (d, J = 8.6 Hz,
2 H), 7.84 (d, J = 8.4 Hz, 2 H).
a-Tosyloxy-p-nitroacetophenone
13C NMR (100 MHz, CDCl3): d = 30.38, 69.87, 123.05, 128.15,
128.25, 130.03, 130.25, 132.35, 133.72, 135.29, 144.70, 145.88,
188.82.
Mp 137 °C (Lit.7 130–131 °C).
IR (KBr): 1180, 1340, 1710 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.47 (s, 3 H), 5.25 (s, 2 H), 7.37
(d, J = 8.3 Hz, 2 H), 7.83 (d, J = 8.3 Hz, 2 H), 8.03 (d, J = 8.9 Hz,
2 H), 8.32 (d, J = 8.9 Hz, 2 H).
HRMS (ESI): m/z [M + Na] calcd for C15H13O6NSNa: 358.0356;
found: 358.0347.
Benzosultams; Typical Procedure
To a solution of N-methoxy-2-phenylethanesulfonamide (0.5
mmol, 107.5 mg) and polymer-supported PhI A10 (1.0 equiv, 444
mg) in CF3CH2OH (3 mL) was added mCPBA (2.0 equiv, 1.0
mmol, 65% purity, 265 mg). The mixture was stirred for 6 h at r.t.
under an argon atmosphere. After the reaction, MeOH (5 mL) was
added and the precipitates were filtered and washed with Et2O. The
filtrate was poured into sat. aq NaHCO3 and extracted with CHCl3
(3 × 15 mL). The organic layer was dried over Na2SO4 and, after re-
moval of the solvent under reduced pressure, N-methoxy-3,4-dihy-
dro-2,1-benzothiazine-2,2-dioxide was obtained in a crude state
(purity >90%). Pure product was obtained by preparative TLC (sil-
ica gel; hexane–CHCl3, 1:5) in 75% yield. Polymer-supported iodo-
benzene was recovered in 92% yield (409 mg).
a-Tosyloxypropiophenone
Mp 68 °C (Lit.7 68–69 °C).
IR (KBr): 1170, 1370, 1700 cm–1.
1H NMR (400 MHz, CDCl3): d = 1.60 (d, J = 7.0 Hz, 3 H), 2.41 (s,
3 H), 5.79 (q, J = 7.0 Hz, 1 H), 7.29 (d, J = 8.1 Hz, 2 H), 7.46 (t,
J = 7.2 Hz, 2 H), 7.75 (d, J = 7.2 Hz, 2 H), 7.88 (d, J = 8.1 Hz, 2 H).
a-Tosyloxy-3-pentanone
Mp 45–46 °C (Lit.2k 43–44 °C).
IR (neat): 1190, 1360, 1720 cm–1.
Synthesis 2010, No. 14, 2355–2360 © Thieme Stuttgart · New York

PAPER
Polymer-Supported Iodobenzene
2359
N-Methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxide
Mp 104.0–106.0 °C.
IR (KBr): 3000, 2950, 2815, 1580, 1480, 1360, 1170 cm–1.
1H NMR (400 MHz, CDCl3): d = 3.42 (t, J = 6.4 Hz, 2 H), 3.50 (td,
J = 6.4, 1.5 Hz, 2 H), 4.08 (s, 3 H), 7.20–7.23 (m, 1 H), 7.31–7.34
(m, 2 H), 7.36–7.40 (m, 1 H).
1H NMR (400 MHz, CDCl3): d = 3.37 (t, J = 6.5 Hz, 2 H), 3.48 (t,
J = 6.5 Hz, 2 H), 4.08 (s, 3 H), 7.14 (d, J = 8.2 Hz, 1 H), 7.27 (dd,
J = 8.2, 2.2 Hz, 1 H), 7.36 (d, J = 2.2 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 27.55 (s), 40.42 (s), 65.95 (p),
125.08 (q), 127.14 (t), 128.92 (t), 130.60 (t), 133.53 (q), 142.90 (q).
MS (EI): m/z = 247 [M]+.
13C NMR (100 MHz, CDCl3): d = 27.86 (s), 40.20 (s), 65.57 (p),
126.72 (q), 127.88 (t), 128.03 (t), 128.90 (t), 129.41 (t), 141.88 (q).
Anal. Calcd for C9H10ClNO3S: C, 43.64; H, 4.07; N, 5.65. Found:
C, 43.39; H, 4.08; N, 5.52.
MS (EI): m/z = 213 [M]+.
Anal. Calcd for C9H11NO3S: C, 50.69; H, 5.20; N, 6.57. Found: C,
50.76; H, 5.32; N, 6.58.
Acknowledgment
Financial support of a Grant-in-Aid for Scientific Research
(No.20550033) from the Ministry of Education, Science, Sports and
Culture in Japan, Academia Showcase Research Grant from the
Japan Chemical Innovation Institute (JCII), and Iodine Research
Project in Chiba University, is gratefully acknowledged.
N-Methoxy-7-methyl-3,4-dihydro-2,1-benzothiazine-2,2-diox-
ide
Mp 119.0–121.0 °C.
IR (KBr): 3000, 2950, 2815, 1620, 1500, 1360, 1170 cm–1.
1H NMR (400 MHz, CDCl3): d = 2.36 (s, 3 H), 3.36 (t, J = 6.6 Hz,
2 H), 3.47 (t, J = 6.6 Hz, 2 H), 4.07 (s, 3 H), 7.08 (d, J = 7.9 Hz,
1 H), 7.12 (d, J = 7.9 Hz, 1 H), 7.18 (s, 1 H).
13C NMR (100 MHz, CDCl3): d = 20.99 (p), 27.56 (s), 40.20 (s),
65.68 (p), 123.61 (q), 128.27 (t), 129.32 (t), 130.07 (t), 138.22 (q),
141.63 (q).
References
(1) (a) For reviews, see: Varvoglis, A. Hypervalent Iodine in
Organic Synthesis; Academic Press: San Diego, 1997.
(b) Moriarty, R. M.; Vaid, R. K. Synthesis 1990, 431.
(c) Stang, P. J. Angew. Chem., Int. Ed. Engl. 1992, 31, 274.
(d) Prakash, O.; Saini, N.; Sharma, P. K. Synlett 1994, 221.
(e) Kitamura, T. J. Synth. Org. Chem. 1995, 53, 893.
(f) Stang, P. J.; Zhdankin, V. V. Chem. Rev. 1996, 96, 1123.
(g) Umemoto, T. Chem. Rev. 1996, 96, 1757. (h) Kita, Y.;
Takada, T.; Tohma, H. Pure Appl. Chem. 1996, 68, 627.
(i) Togo, H.; Hoshina, Y.; Nogami, G.; Yokoyama, M. J.
Synth. Org. Chem. 1997, 55, 90. (j) Varvoglis, A.
MS (EI): m/z = 227 [M]+.
Anal. Calcd for C10H13NO3S: C, 52.85; H, 5.77; N, 6.16. Found: C,
52.80; H, 5.69; N, 6.14.
N-Methoxy-7-chloromethyl-3,4-dihydro-2,1-benzothiazine-2,2-
dioxide
Mp 120.0–122.5 °C.
IR (paraffin oil): 1360, 1280, 1236, 1170 cm–1.
1H NMR (400 MHz, CDCl3): d = 3.40 (t, J = 6.5 Hz, 2 H), 3.49 (t,
J = 6.5 Hz, 2 H), 4.09 (s, 3 H), 4.58 (s, 2 H), 7.21 (d, J = 8.0 Hz,
1 H), 7.34 (dd, J = 8.0, 1.9 Hz, 1 H), 7.39 (d, J = 1.9 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 27.61 (s), 40.11 (s), 44.92 (s),
65.69 (p), 126.69 (q), 127.44 (t), 128.80 (t), 129.84 (t), 137.59 (q),
141.96 (q).
Tetrahedron 1997, 53, 1179. (k) Zhdankin, V. V. Rev.
Heteroat. Chem. 1997, 17, 133. (l) Muraki, T.; Togo, H.;
Yokoyama, M. Rev. Heteroat. Chem. 1997, 17, 213.
(m) Kitamura, T.; Fujiwara, Y. Org. Prep. Proced. Int. 1997,
29, 409. (n) Varvoglis, A.; Spyroudis, S. Synlett 1998, 221.
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10927. (p) Moriarty, R. M.; Prakash, O. Adv. Heterocycl.
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527.
MS (FAB): m/z = 261 [M + 1]+.
Anal. Calcd for C10H12ClNO3S·1/5H2O: C, 45.44; H, 4.69; N, 5.30.
Found: C, 45.44; H, 4.62; N, 5.24.
(2) For reviews, see: (a) Moriarty, R. M.; Vaid, R. K.; Koser, G.
F. Synlett 1990, 365. (b) Koser, G. F. Aldrichimica Acta
2001, 34, 89. (c) Papers: Prakash, O.; Saini, N.; Sharma, P.
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Wettach, R. H.; Troup, J. M.; Frenz, B. A. J. Org. Chem.
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Relenyi, A. G.; Kalos, A. N.; Rebrovic, L.; Wettach, R. H.
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Penmasta, R.; Awasthi, A. K.; Epa, W. R.; Prakash, I. J. Org.
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Hopkins, T. E.; Vaid, B. K.; Prakash, O. Tetrahedron Lett.
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N-Methoxy-7-bromo-3,4-dihydro-2,1-benzothiazine-2,2-diox-
ide
Mp 138.0–139.5 °C.
IR (paraffin oil): 1360, 1292, 1167 cm–1.
1H NMR (400 MHz, CDCl3): d = 3.35 (t, J = 6.6 Hz, 2 H), 3.48 (t,
J = 6.6 Hz, 2 H), 4.08 (s, 3 H), 7.08 (d, J = 8.4 Hz, 1 H), 7.42 (dd,
J = 8.4, 2.0 Hz, 1 H), 7.52 (d, J = 2.0 Hz, 1 H).
13C NMR (100 MHz, CDCl3): d = 27.50 (s), 40.24 (s), 65.86 (p),
120.94 (q), 125.51 (q), 130.00 (t), 130.73 (t), 131.71 (t), 142.94 (q).
MS (FAB): m/z = 291[M + 1]+.
Anal. Calcd for C9H10BrNO3S: C, 37.00; H, 3.45; N, 4.79. Found:
C, 36.87; H, 3.43; N, 4.75.
(l) Moriarty, R. M.; Vaid, B. K.; Duncan, M. P.; Levy, S. G.;
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N-Methoxy-7-chloro-3,4-dihydro-2,1-benzothiazine-2,2-diox-
ide
Mp 123.0–125.0 °C.
IR (KBr): 3000, 2950, 2815, 1600, 1480, 1360, 1160 cm–1.
Synthesis 2010, No. 14, 2355–2360 © Thieme Stuttgart · New York

2360
Y. Suzuki, H. Togo
PAPER
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Synthesis 2010, No. 14, 2355–2360 © Thieme Stuttgart · New York