TEMPO-mediated oxidation of alcohols with ion-supported (diacetoxyiodo)benzenes

Article abstract of DOI:10.1055/s-0031-1290766

The oxidation of secondary alcohols and primary alcohols with novel ion-supported (diacetoxyiodo)benzenes (IS-DIB) in the presence of a catalytic amount of 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) in dichloromethane at room temperature proceeded efficiently to provide the corresponding ketones and aldehydes, respectively, in good yields with high purity. Isolation of the product was easily accomplished by simple diethyl ether extraction of the reaction mixture and subsequent removal of the solvent from the extract. Moreover, ion-supported iodobenzenes, which were co-products derived from IS-DIB in the present oxidation, were recovered in good yields and could be re-oxidized to IS-DIB for reuse in the same oxidation. Georg Thieme Verlag Stuttgart · New York.

Full text of DOI:10.1055/s-0031-1290766

1250▌
LETTER
Letter
TEMPO-Mediated Oxidation of Alcohols with Ion-Supported (Diacetoxy
iodo)benzenes
Oxidation of Alcohols with Ion-Supported (Diacetoxyiodo)benzenes
Yusuke Suzuki, Masataka Iinuma, Katsuhiko Moriyama, Hideo Togo*
Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
Received: 31.01.2012; Accepted after revision: 15.02.2012
of nonexplosive trivalent iodine, and the lack of unpleas-
Abstract: The oxidation of secondary alcohols and primary alco-
ant odor.5 However, the reaction produces a stoichiomet-
hols with novel ion-supported (diacetoxyiodo)benzenes (IS-DIB) in
ric amount of iodobenzene as a co-product, which must be
purified by troublesome column chromatography on silica
the presence of a catalytic amount of 2,2,6,6-tetramethylpiperidine-
1-oxy radical (TEMPO) in dichloromethane at room temperature
proceeded efficiently to provide the corresponding ketones and al- gel. To solve this problem and simplify the isolation of the
dehydes, respectively, in good yields with high purity. Isolation of
the product was easily accomplished by simple diethyl ether extrac-
tion of the reaction mixture and subsequent removal of the solvent
are still drawbacks, such as the low purity of carbonyl
from the extract. Moreover, ion-supported iodobenzenes, which
were co-products derived from IS-DIB in the present oxidation,
desired product, the polymer-supported DIB, poly[4-(di-
acetoxyiodo)styrene], was developed.5b However, there
compounds after filtration of the reaction mixture due to
the presence of low-molecular weight polymer-supported
iodobenzenes. Moreover, the elemental analysis of
polymer-supported DIB must be carried out in each
preparation of polymer-supported DIB to evaluate the
loading rate of (diacetoxy)iodo groups in the polymer-
supported DIB. Recently, the oxidation of alcohols with a
1-(4′-diacetoxyiodobenzene)-3-methylimidazolium tetra-
fluoroborate/KBr/[emim]BF4 system6a and a 1-(4′-di-
acetoxyiodobenzene)-3-methylimidazolium tetrafluoro-
borate/3-methylimidazolium-supported TEMPO/water
system6b was reported. However, there are still certain
drawbacks, such as addition to carbon–carbon double
bond of substrates by bromonium ion species and solubil-
ity of substrates in water. Here, as part of our ongoing
studies of trivalent iodines for organic synthesis,7 we
would like to report the TEMPO-mediated oxidation of al-
cohols to ketones or aldehydes with ion-supported (di-
acetoxyiodo)benzenes (IS-DIB).
were recovered in good yields and could be re-oxidized to IS-DIB
for reuse in the same oxidation.
Key words: oxidation, ion-supported (diacetoxyiodo)benzene, al-
cohol, TEMPO, aldehyde, ketone, reuse
Organic synthesis that features high efficiency, low toxic-
ity, little odor, and atom economy, and produces a mini-
mal amount of reaction waste is very important for green
chemistry. Therefore, efficient organic synthesis with less
toxic reagents has been pursued actively.1 The oxidation
of alcohols to ketones or aldehydes is one of the most fun-
damental, widespread, and important reactions in both re-
search laboratories and production plants.2 Among the
various methods for the oxidation of alcohols to ketones
or aldehydes, the Swern oxidation3 with dimethyl sulfox-
ide (DMSO) and oxalyl chloride or trifluoroacetic
anhydride and the Dess–Martin oxidation4 with 1,1,1-
triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-2-one
(Dess–Martin periodinane) are the most popular, effi-
cient, and selective methods for the preparation of ketones
or aldehydes from alcohols in organic synthesis, because
both reactions do not require any toxic metals, that is, they
are metal-free oxidation reactions and proceed under mild
and nearly neutral conditions. However, each reaction still
has a major drawback. Dimethyl sulfide, a co-product of
the Swern oxidation, is a highly malodorous volatile com-
pound that makes handling of the reaction extremely dif-
ficult, and Dess–Martin pentavalent periodinane is
explosive. In 1997, the 2,2,6,6-tetramethylpiperidine-1-
oxy radical (TEMPO)-mediated oxidation of alcohols to
ketones or aldehydes with (diacetoxyiodo)benzene (DIB)
in dichloromethane (CH2Cl2) at room temperature was
reported5a and has become a very popular method for the
efficient and selective oxidation of alcohols to ketones or
aldehydes, due to simple experimental operation, the use
Three IS-DIB, N-methyl-N-[3-(4′-diacetoxyiodo)phenyl-
1-propyl]pyrrolidium 4′′-methylbenzenesulfonate A,
N-methyl-N-[3-(4′-diacetoxyiodo)phenoxy-1-propyl]-
pyrrolidium 4′′-methylbenzenesulfonate B, and N-[3-(4′-
diacetoxyiodo)phenoxy-1-propyl]-N,N,N-trimethylammo-
nium 4′′-methylbenzenesulfonate C (Figure 1), were pre-
Me
N
IS-DIB A
(AcO)2I
OTs
Me
O
N
IS-DIB B
OTs
Me
(AcO)2I
Me
Me
O
N
IS-DIB C
SYNLETT 2012, 23, 1250–1256
Advanced online publication: 20.04.2012
OTs
(AcO)2I
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6
DOI: 10.1055/s-0031-1290766; Art ID: ST-2012-U0093-L
© Georg Thieme Verlag Stuttgart · New York
Figure 1

LETTER
Oxidation of Alcohols with Ion-Supported (Diacetoxyiodo)benzenes
1251
pared by the oxidation of N-methyl-N-[3-(4′-iodophenyl)- 4′′-methylbenzenesulfonate (pre-C),8 respectively, with
1-propyl]pyrrolidinium
4′′-methylbenzene-sulfonate sodium perborate in acetic acid at 45 °C.9 Precursors pre-
(pre-A), N-methyl-N-[3-(4′-iodophenoxy)-1-propyl]pyr- A, pre-B, and pre-C were easily prepared from commer-
rolidinium 4′′-methylbenzenesulfonate (pre-B), and N-[3- cially available 3-phenylpropanoic acid in four steps and
(4′-iodophenoxy)-1-propyl]-N,N,N-trimethylammonium
p-iodophenol in three steps, respectively.
Table 1 Oxidation of Alcohols with IS-DIB A–C
IS-DIB A, B, or C (1.5 equiv), TEMPO
(10 mol%)
aldehyde or ketone
alcohol
CH2Cl2 (0.25 M), r.t.
2
1
IS-DIB or DIB
Ketone or aldehyde (2)
time (h), yield (%) [purity (%)]
O
O
2a
2b
IS-DIB A
IS-DIB B
IS-DIB C
DIB
12 , 99 [99]
15, 99 [99]
12, 99 [99]
18, 99 [97]
10, 99 [99]
9, 97 [98]
5, 99 [48]
O
O
O
2d
2c
IS-DIB A
IS-DIB B
IS-DIB C
4, 94 [99]
9, 97 [99]
10.5, 93 [98]
9, 99 [99]
4.5, 99 [99]
8, 97 [97]
O
O
Cl
2f
2e
IS-DIB A
IS-DIB B
IS-DIB C
6, 96 [99]
2, 95 [99]
2, 98 [99]
6, 98 [99]
1.5, 98 [99]
8, 98 [99]
O
O
O
O
2h
2g
IS-DIB A
IS-DIB B
IS-DIB C
3.5, 98 [99]
8, 99 [99]
3.5, 97 [99]
8, 95 [92]
6, 99 [99]
6, 98 [98]
O
O
S
2i
2j
© Georg Thieme Verlag Stuttgart · New York
Synlett 2012, 23, 1250–1256

1252
Y. Suzuki et al.
LETTER
Table 1 Oxidation of Alcohols with IS-DIB A–C (continued)
IS-DIB A, B, or C (1.5 equiv), TEMPO
(10 mol%)
aldehyde or ketone
alcohol
CH2Cl2 (0.25 M), r.t.
2
1
IS-DIB or DIB
Ketone or aldehyde (2)
time (h), yield (%) [purity (%)]
IS-DIB A
IS-DIB B
IS-DIB C
DIB
2, 99 [99]
3, 99 [99]
6, 99 [99]
1.5, 99 [48]
1.5, 97 [99]
1.5, 94 [99]
2, 99 [98]
O
O
2k
2l
IS-DIB A
IS-DIB B
IS-DIB C
IS-DIB Aa
IS-DIB Ba
IS-DIB Ca
2, 99 [99]
2, 98 [99]
4, 98 [99]
1.5, 95 [99]
2, 99 [99]
4, 99 [98]
2, 97 [99]
1.5, 92 [99]
2, 99 [99]
1.5, 96 [99]
2, 98 [98]
2, 98 [99]
O
O
OTs
2n
2m
IS-DIB A
IS-DIB B
IS-DIB C
DIB
10, 95 [97]
7, 80 [80]
12, 84 [83]
18, 91 [88]
4, 91 [50]
6, 79 [79]
8, 81 [81]
2, 99 [48]
O
TBSO
O
2p
2o
IS-DIB A
IS-DIB B
IS-DIB C
DIB
8, 96 [99]
16, 92 [95]
16, 97 [97]
8, 86 [85]
7, 97 [49]
7, 95 [99]
8, 97 [97]
6, 97 [49]
Synlett 2012, 23, 1250–1256
© Georg Thieme Verlag Stuttgart · New York

LETTER
Oxidation of Alcohols with Ion-Supported (Diacetoxyiodo)benzenes
1253
Table 1 Oxidation of Alcohols with IS-DIB A–C (continued)
IS-DIB A, B, or C (1.5 equiv), TEMPO
(10 mol%)
aldehyde or ketone
alcohol
CH2Cl2 (0.25 M), r.t.
2
1
IS-DIB or DIB
Ketone or aldehyde (2)
time (h), yield (%) [purity (%)]
O
OBn
OBn
O
O
BnO
OBn
2q
2r
IS-DIB A
IS-DIB B
IS-DIB C
DIB
9, 96 [99]
6, 95 [99]
4, 98 [99]
5, 99 [99]
6, 94 [94]
1.5, 97 [48]
12, 99 [99]
4.5, 99 [48]
a Recovered and regenerated IS-DIB was used.
The oxidation of secondary and primary alcohols with IS- alcohol (1f), piperonyl alcohol (1g), 4-phenylbenzyl alco-
DIB A, B, C, or DIB in the presence of TEMPO in CH2Cl2 hol (1h), 2-thiophenemethanol (1i), geraniol (1j), and
at room temperature was carried out by means of the same trans-cinnamyl alcohol (1k), with IS-DIB A, B, and C un-
experimental procedure as that described in the litera- der the same conditions and procedure provided the corre-
ture.5a Thus, to a solution of IS-DIB A, B, or C (1.5 equiv) sponding aromatic aldehydes 2e–i and α,β-unsaturated
in CH2Cl2 were added alcohol (1.0 equiv) and TEMPO aldehydes 2j and 2k in good yields with high purity, re-
(0.1 equiv). Then, the mixture was stirred at room temper- spectively. The oxidations of primary alcohols, such as β-
ature. After the disappearance of alcohol, the solvent was citronellol (1l), 1-adamantanemethanol (1m), and 8-(p-
removed. Water was added to the residue, and the mixture methylbenzenesulfonyloxy)-1-octanol (1n), with IS-DIB
was extracted with diethyl ether three times. After drying A, B, and C in the presence of TEMPO at room tempera-
the solution with Na2SO4, filtration, and removal of the ture provided the corresponding aldehydes 2l–n in good
solvent, ketone or aldehyde was obtained in good yield yields with high purity, respectively, although the yield
with high purity.10 Thus, when diphenylmethanol (1a) and purity were slightly decreased in the oxidation of 8-
was used as the substrate in the oxidation with IS-DIB A, (p-methylbenzenesulfonyloxy)-1-octanol (1n). When
B, and C, benzophenone (2a) was obtained in 99%, 99%, DIB was used as the oxidant in the same oxidation of 1-
and 97% yields with 99%, 99%, and 98% purity, respec- adamantanemethanol (1m) and 8-(p-methylbenzenesulfo-
tively, as shown in Table 1. Here, use of an excess amount nyloxy)-1-octanol (1n) under the same conditions and
of IS-DIB suppressed the contamination of TEMPO into procedure, the corresponding aldehydes 2m and 2n were
the diethyl ether extracts from the reaction mixture. On obtained in good yields, respectively. However, the purity
the other hand, when DIB was used as the oxidant for the was 50% and 48%, respectively, again due to the presence
oxidation of diphenylmethanol (1a) under the same con- of iodobenzene. The same TEMPO-mediated oxidation of
ditions and procedure, benzophenone (2a) was obtained in ketones, such as β-cholestanol (1o), 4-(tert-butyldimeth-
99% yield, but its purity was 48% due to the presence of ylsilyloxy)-1-cyclohexanol (1p), borneol (1q), and
iodobenzene. Therefore, the purification of benzophenone 2,3,4,6-tetra-O-benzyl-D-glucose (1r), with IS-DIB A, B,
by column chromatography on silica gel was required. and C gave the corresponding ketones 2o–r in good yields
When IS-DIB A, B, or C was used as the oxidant, the ox- with high purity, respectively.
idation product was obtained in good yield with high pu-
rity by simple diethyl ether extraction of the reaction
On the other hand, the purity of ketones 2o–r obtained
with DIB was 49%, 49%, 48%, and 48%, respectively, al-
mixture and subsequent removal of the solvent from the
though the yields were quite good.
extract. The same oxidation reactions of 9-fluorenol (1b),
Then, the reuse of IS-DIB A, B, and C in the oxidation of
alcohols in the presence of TEMPO was carried out. After
the extraction of the oxidation product from the reaction
mixture with diethyl ether, the aqueous solution was ex-
1-phenyl-1-propanol (1c), and 1-(5′-methylfuran-2′-yl)-1-
pentanol (1d) were carried out under the same conditions
and procedure to give the corresponding ketones 2b, 2c,
and 2d in good yields with high purity, respectively.
Moreover, the same treatment of benzylic and allylic alco-
hols, such as p-chlorobenzyl alcohol (1e), p-methylbenzyl
tracted with chloroform to recover ion-supported iodo-
benzenes in good yields.10 The recovered ion-supported
© Georg Thieme Verlag Stuttgart · New York
Synlett 2012, 23, 1250–1256

1254
Y. Suzuki et al.
LETTER
K.; Togo, H. Synthesis 2003, 21. (c) But, T. Y. S.; Tashino,
Y.; Togo, H.; Toy, P. H. Org. Biomol. Chem. 2005, 3, 970.
(d) Piancatelli, G.; Leonelli, F. Org. Synth. 2006, 83, 18.
(e) Vatele, J. Tetrahedron Lett. 2006, 47, 715. (f) Vugts, D.
J.; Veum, L.; al-Mafraji, K.; Lemmens, R.; Schmitz, R. F.;
de Kanter, F. J. J.; Groen, M. B.; Hanefeld, U.; Orru, R. V.
A. Eur. J. Org. Chem. 2006, 1672. (g) Fuwa, H.;
Yamaguchi, M.; Sasaki, M. Org. Lett. 2010, 12, 1848.
(h) Uchiro, H.; Kato, R.; Arai, Y.; Hasegawa, M.;
Kobayakawa, Y. Org. Lett. 2011, 13, 6268. (i) Shimokawa,
J.; Harada, T.; Yokoshima, S.; Fukuyama, T. J. Am. Chem.
Soc. 2011, 133, 17634.
iodobenzenes were re-oxidized with sodium peroxoborate
in acetic acid at 45 °C to regenerate IS-DIB A, B, and C,
respectively, in good yields. Reuse of the recovered and
regenerated IS-DIB A, B, and C for the oxidation of trans-
cinnamyl alcohol (1k) and β-citronellol (1l) in the pres-
ence of TEMPO under the same conditions as those of the
first reactions provided the corresponding aldehydes 2k
and 2l in good yields with high purity again, as shown in
Table 1. Thus, IS-DIB A, B, and C can be regenerated and
reused for the same oxidation.
In conclusion, the TEMPO-mediated oxidation of second-
ary and primary alcohols with IS-DIB A, B, and C provid-
ed the corresponding ketones and aldehydes in good
yields with high purity by simple diethyl ether extraction
of the reaction mixture and subsequent removal of the sol-
vent from the extract. Moreover, ion-supported iodoben-
zenes, which were the co-products of the present reactions
and derived from IS-DIB A, B, and C, could be recovered
in good yields and regenerated and reused for the same
oxidation of alcohols, maintaining high yields and high
purity of the products. Thus, the present IS-DIB A, B, and
C are simplified reagents for the isolation of ketones or al-
dehydes, and are user-friendly and environmentally be-
nign reagents for the TEMPO-mediated oxidation of
alcohols.
(6) (a) Weixing, Q.; Erlei, J.; Weiliang, B.; Yongmin, Z. Angew.
Chem. Int. Ed. 2005, 44, 952. (b) Weixing, Q.; Erlei, J.;
Weiliang, B.; Yongmin, Z. Tetrahedron 2006, 62, 556.
(7) (a) Yamamoto, Y.; Togo, H. Synlett 2006, 798.
(b) Yamamoto, Y.; Kawano, Y.; Toy, P. H.; Togo, H.
Tetrahedron 2007, 63, 4680. (c) Akiike, J.; Yamamoto, Y.;
Togo, H. Synlett 2007, 2168. (d) Moroda, A.; Togo, H.
Synthesis 2008, 1257. (e) Ishiwata, Y.; Togo, H.
Tetrahedron Lett. 2009, 50, 5354. (f) Suzuki, Y.; Togo, H.
Synthesis 2010, 2355. (g) Kawano, Y.; Togo, H.
Tetrahedron 2009, 65, 6251. (h) Ishiwata, Y.; Togo, H.
Tetrahedron 2009, 65, 10720. (i) Tanaka, A.; Togo, H.
Synlett 2009, 3360.
(8) Typical Procedure for the Preparation of N-Methyl-N-
[3-(4′-iodophenyl)-1-propyl]pyrrolidinium 4′′-Methyl-
benzenesulfonate (pre-A): To a solution of 3-(4′-
iodophenyl)-1-propyl tosylate (5 mmol, 2.08 g) in MeCN
(20 mL) was added 1-methylpyrrolidine (1.10 equiv, 5.50
mmol, 0.585 mL). The mixture was stirred for 16 h at 60 °C.
After the reaction, the reaction mixture was concentrated in
vacuo. H2O (20 mL) was added to the residue, the aqueous
layer was washed with Et2O (30 mL) once and then extracted
with CHCl3 (3 × 30 mL). The organic layer was dried over
Na2SO4. Then, removal of the solvent under reduced
pressure afforded N-methyl-N-[3-(4′-iodophenyl)-1-
propyl]pyrrolidinium 4′′-methylbenzenesulfonate (pre-A) in
99% yield. If necessary, the residue was washed with EtOAc
to afford the product in >99% purity. N-Methyl-N-[3-(4′-
iodophenoxy)-1-propyl]pyrrolidinium 4′′-methylbenzene-
sulfonate (pre-B) and N-[3-(4′-iodophenoxy)-1-propyl]-
N,N,N-trimethylammonium 4′′-methylbenzenesulfonate
(pre-C) were prepared in 99% yield and 99% yield,
respectively, by the same procedure.
Acknowledgement
Financial support in the form of a Grant-in-Aid for Scientific Re-
search (No. 23655142) from the Ministry of Education, Culture,
Sports, Science, and Technology in Japan, Iodine Research Project
in Chiba University, and Futaba Electronics Memorial Foundation
is gratefully acknowledged.
Supporting Information for this article is available online at
http://www.thieme-connect.com/ejournals/toc/synlett.onmorinftIangoimnuSpinorttfoIangiStupor
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4′′-Methylbenzenesulfonate: mp 127–129 °C. IR (Nujol):
1185, 798 cm–1. 1H NMR (400 MHz, CDCl3): δ = 1.93–2.03
(m, 2 H), 2.05–2.10 (m, 4 H), 2.31 (s, 3 H), 2.57 (t, J = 7.5
Hz, 2 H), 3.09 (s, 3 H), 3.50 (t, J = 6.7 Hz, 2 H), 3.53–3.65
(m, 4 H), 6.90 (d, J = 8.2 Hz, 2 H), 7.11 (d, J = 8.2 Hz, 2 H),
7.54 (d, J = 8.2 Hz, 2 H), 7.73 (d, J = 8.2 Hz, 2 H). 13C NMR
(100 MHz, CDCl3): δ = 21.27, 21.54, 25.44, 31.57, 48.26,
63.20, 64.20, 91.63, 125.79, 128.67, 130.53, 137.65, 139.25,
139.48, 144.02. ESI-HMRS: m/z calcd for C14H21NI [M+]:
330.0713; found: 330.0705.
N-Methyl-N-[3-(4′-iodophenoxy)-1-propyl]pyrroli-
dinium 4′′-Methylbenzenesulfonate: mp 114–116 °C. IR
(Nujol): 1195, 1010, 818 cm–1. 1H NMR (400 MHz, CDCl3):
δ = 2.08–2.23 (m, 6 H), 2.30 (s, 3 H), 3.15 (s, 3 H), 3.54–
3.72 (m, 6 H), 3.92 (t, J = 5.8 Hz, 2 H), 6.60 (d, J = 9.1 Hz,
2 H), 7.09 (d, J = 8.2 Hz, 2 H), 7.50 (d, J = 9.1 Hz, 2 H), 7.71
(d, J = 8.2 Hz, 2 H). 13C NMR (100 MHz, CDCl3):
δ = 21.23, 21.55, 23.99, 48.27, 61.16, 64.27, 64.38, 83.24,
116.90, 125.70, 128.63, 138.22, 139.22, 144.02, 158.04.
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found: 346.0655.
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Synlett 2012, 23, 1250–1256
© Georg Thieme Verlag Stuttgart · New York

LETTER
Oxidation of Alcohols with Ion-Supported (Diacetoxyiodo)benzenes
1255
N-[3-(4′-Iodophenoxy)-1-propyl]-N,N,N-trimethyl-
2 H), 3.28 (s, 9 H), 3.67 (t, J = 8.4 Hz, 2 H), 4.13 (t, J = 5.5
Hz, 2 H), 6.96 (d, J = 9.1 Hz, 2 H), 8.00 (d, J = 9.1 Hz, 2 H);
δ (anion TsO–) = 2.31 (s, 3 H), 7.12 (d, J = 8.2 Hz, 2 H), 7.71
(d, J = 8.2 Hz, 2 H). 13C NMR (100 MHz, CDCl3): δ = 20.24,
21.43, 23.03, 53.44, 64.12, 64.68, 111.79, 116.98, 126.35,
129.23, 137.09, 138.19, 142.44, 160.76, 176.63. ESI-
HMRS: m/z calcd for C16H25NI [M+]:438.0772; found:
438.0760.
ammonium 4′′-Methylbenzenesulfonate: mp 222–226 °C.
IR (KBr) 1285, 1010, 816 cm–1. 1H NMR (400 MHz,
CDCl3): δ = 2.12–2.19 (m, 2 H), 2.29 (s, 3 H), 3.08 (s, 9 H),
3.46 (t, J = 8.3 Hz, 2 H), 4.02 (t, J = 6.0 Hz, 2 H), 6.80 (d,
J = 9.0 Hz, 2 H), 7.12 (d, J = 7.9 Hz, 2 H), 7.47 (d, J = 7.9
Hz, 2 H), 7.61 (d, J = 9.0 Hz, 2 H). 13C NMR (100 MHz,
DMSO): δ = 20.74, 22.42, 52.25, 62.84, 64.84, 83.53,
117.29, 125.44, 128.00, 137.51, 138.01, 145.80, 158.04.
HRMS (APPI): m/z calcd for C12H19ONI [M+]: 320.0506;
found: 320.0499.
Typical Procedure for the Preparation of N-Methyl-N-
[3-(4′-diacetoxyiodo)phenyl-1-propyl]pyrrolidinium 4′′-
Methylbenzenesulfonate (IS-DIB A): To a solution of
N-methyl-N-[3-(4′-iodophenyl)-1-propyl]pyrrolidium 4′′-
methylbenzenesulfonate (5 mmol, 2.50 g) in AcOH (50 mL)
was added portionwise NaBO3·4H2O (10 equiv, 50 mmol,
7.69 g). The mixture was stirred for 15 h at 45 °C. After the
reaction, the reaction mixture was concentrated in vacuo,
then the residue was dissolved in H2O (50 mL), and the
obtained mixture was washed with Et2O (50 mL) once.
Then, the aqueous layer was extracted with CHCl3 (5 × 30
mL). The organic layer was dried over Na2SO4. Removal of
the solvent under reduced pressure afforded N-methyl-N-
[3-(4′-diacetoxyiodo)-phenyl-1-propyl]pyrrolidium 4′′-
methylbenzenesulfonate in the range of 60–70% yields
(counteranion; TsO–/AcO– = 1:1; IS-DIB A). The
(9) McKillop, A.; Kemp, D. Tetrahedron 1989, 45, 3299.
(10) General Procedure for the Oxidation of Alcohols with IS-
DIB A, B, and C in the Presence of TEMPO: To a solution
of IS-DIB A, B, or C (1.5 equiv, 0.75 mmol) in CH2Cl2 (2
mL) were added alcohol (0.5 mmol) and TEMPO (10 mol%,
0.05 mmol). Then, the reaction mixture was stirred for 2 h at
r.t. Then, the reaction mixture was concentrated in vacuo,
H2O (20 mL) was added to the residue, and the aqueous layer
was extracted with Et2O (3 × 20 mL). The organic layer was
dried over Na2SO4. Removal of the solvent under reduced
pressure afforded the product (ketone or aldehyde), and
purity of the product was estimated by 1H NMR
spectroscopy. On the other hand, the aqueous layer was
extracted with CHCl3 three times (3 × 20 mL). Then, the
organic layer was washed with aq Na2SO3 and brine. The
organic layer was dried over Na2SO4, and removal of the
solvent under reduced pressure afforded ion-supported
iodobenzene (recovery rate: 75–90%).
Typical Procedure for the Regeneration of N-methyl-N-
[3-(4′-diacetoxyiodo)phenyl-1-propyl]pyrrolidinium 4′′-
Methylbenzenesulfonate (IS-DIB A): To a solution of N-
methyl-N-[3-(4′-iodophenyl)-1-propyl]pyrrolidinium 4′′-
methylbenzenesulfonate (5 mmol, 2.50 g) in AcOH (50 mL)
was added portionwise NaBO3·4H2O (10 equiv, 50 mmol,
7.69 g). The mixture was stirred for 15 h at 45 °C. After the
reaction, the reaction mixture was concentrated, and H2O
(20 mL) was added to the residue. Then the aqueous solution
was washed with H2O once, and then extracted with CHCl3
five times (3 × 30 mL). The organic layer was dried over
Na2SO4. Then, removal of the solvent at 45 °C under
reduced pressure afforded N-methyl-N-[3-(4′-diacetoxy-
iodo)phenyl-1-propyl]pyrrolidinium 4′′-methylbenzene-
sulfonate (TsO–/AcO– = 1:1). The counteranion was
completely converted into the tosylate anion by the stirring
treatment of the obtained IS-DIB A with PTSA·H2O (1.0
equiv) in MeCN (20 mL) at r.t. overnight. Then the solvent
was removed and, and H2O (20 mL) was added to the
residue. The aqueous layer was washed with Et2O and then
extracted with CHCl3 (3 × 30mL). Finally, removal of the
solvent gave the regenerated IS-DIB A.
counteranion was completely converted into the tosylate
anion by the stirring treatment of the obtained IS-DIB A with
PTSA·H2O (1.0 equiv) in MeCN (20 mL) at r.t. overnight.
Then the solvent was removed, and H2O (20 mL) was added
to the residue. The aqueous layer was washed with Et2O and
then extracted with CHCl3 (3 × 30 mL). Finally, removal of
the solvent gave IS-DIB A. IS-DIB B and C were prepared
from pre-B and pre-C in the range of 60–70% yields,
respectively, by the same procedure. The purity of IS-DIB
A, B, and C was estimated to be nearly 90% by 1H NMR
spectroscopy, due to containing a trace amount of pre-A,
pre-B, and pre-C, respectively.
N-Methyl-N-[3-(4′-diacetoxyiodo)phenyl-1-propyl]-
pyrrolidinium 4′′-Methylbenzenesulfonate (IS-DIB A):
viscous oil. IR (neat): 1646, 1556, 1272, 799 cm–1. 1H NMR
(400 MHz, CDCl3): δ (cation) = 2.00 (s, 6 H), 2.06–2.29 (m,
6 H), 2.78 (t, J = 7.8 Hz, 2 H), 3.14 (s, 3 H), 3.54–3.73 (m, 6
H), 7.36 (d, J = 8.6 Hz, 2 H), 7.99 (d, J = 8.6 Hz, 2 H); δ
(anion TsO–) = 2.35 (s, 3 H), 7.17 (d, J = 8.2 Hz, 2 H), 7.77
(d, J = 8.2 Hz, 2 H). 13C NMR (100 MHz, CDCl3):
δ = 20.28, 21.50, 21.80, 25.27, 31.83, 48.34, 63.47, 64.33,
118.75, 125.68, 128.66, 131.08, 135.11, 139.61, 143.31,
144.49, 176.46. ESI-HMRS: m/z calcd for C18H27O4NI [M+]:
448.0979; found: 448.0967.
Regenerated IS-DIB B and C were prepared from recovered
N-methyl-N-[3-(4′-iodophenoxy)-1-propyl]pyrrolidinium
4′′-methylbenzenesulfonate (pre-B), and N-[3-(4′-
N-Methyl-N-[3-(4′-diacetoxyiodo)phenoxy-1-propyl]-
pyrrolidinium 4′′-Methylbenzenesulfonate (IS-DIB B):
viscous oil. IR (neat): 1650, 1583, 1275, 1010, 823 cm–1. 1H
NMR (400 MHz, CDCl3): δ (cation) = 1.98 (s, 6 H), 2.18–
2.29 (m, 6 H), 3.17 (s, 3 H), 3.59–3.74 (m, 6 H), 4.13 (t,
J = 5.6 Hz, 2 H), 6.93 (d, J = 9.1 Hz, 2 H), 7.97 (d, J = 9.1
Hz, 2 H); δ (anion TsO–) = 2.31 (s, 3 H), 7.12 (d, J = 8.2 Hz,
2 H), 7.73 (d, J = 8.2 Hz, 2 H). 13C NMR (100 MHz, CDCl3):
δ = 20.28, 21.58, 22.03, 23.85, 48.46, 61.51, 64.51, 64.85,
111.67, 117.03, 125.66, 128.66, 137.02, 138.20, 143.32,
160.77, 176.43. ESI-HMRS: m/z calcd for C18H27O5NI [M+]:
464.0928; found: 464.0919.
iodophenoxy)-1-propyl]-N,N,N-trimethylammonium 4′′-
methylbenzenesulfonate (pre-C), respectively, by the same
method and conditions.
Most of ketones and aldehydes in the present study are
commercially available, and they are identified with
authentic samples, except for the following products.
1-(5′-Methylfuran-2′-yl)-1-pentanone (2d): oil. IR (neat):
3121, 2931, 2827, 1671, 1518, 1452, 876 cm–1. 1H NMR
(400 MHz, CDCl3): δ = 0.94 (t, J = 7.5 Hz, 3 H), 1.39 (sext,
J = 7.5 Hz, 2 H), 1.69 (quin, J = 7.5 Hz, 2 H), 2.39 (s, 3 H),
2.75 (t, J = 7.5 Hz, 2 H), 6.14 (d, J = 3.4 Hz, 1 H), 7.09 (d,
J = 3.4 Hz, 1 H). 13C NMR (100 MHz, CDCl3): δ = 13.15,
13.33, 21.76, 26.11, 37.17, 108.10, 118.22, 150.84, 156.84,
188.40. ESI-HMRS: m/z calcd for C10H15O2 [M + H]:
167.1067; found: 167.1065.
3-[4′-(Diacetoxyiodo)phenoxy]-1-propyl-N,N,N-tri-
methylammonium 4′′-Methylbenzenesulfonate (IS-DIB
C): viscous oil. IR (neat): 1650, 1243, 1040, 812 cm–1.
1H NMR (400 MHz, CDCl3): δ = 1.98 (s 6 H), 2.30–2.35 (m
© Georg Thieme Verlag Stuttgart · New York
Synlett 2012, 23, 1250–1256

1256
Y. Suzuki et al.
LETTER
1-Adamantanecarboxaldehyde (2m): mp 140–142 °C
(lit.[11] mp 146–148 °C). IR (Nujol): 2815, 2698, 1722
cm–1. 1H NMR (400 MHz, CDCl3): δ = 1.68–1.80 (m, 12 H),
2.03–2.09 (m, 3 H), 9.32 (s, 1 H). 13C NMR (100 MHz,
CDCl3): δ = 27.31, 35.80, 36.52, 44.82, 206.09.
8-(4′-Methylbenzenesulfonyloxy)octanal (2n): oil. IR
(neat): 2859, 2723, 1723, 1359, 1176 cm–1. 1H NMR (400
MHz, CDCl3): δ = 1.21–1.36 (m, 6 H), 1.54–1.58 (m, 4 H),
2.41 (t, J = 7.4 Hz, 2 H), 2.45 (s, 3 H), 4.02 (t, J = 6.5 Hz, 2
H), 7.35 (d, J = 8.2 Hz, 2 H), 7.78 (d, J = 8.2 Hz, 2 H), 9.73–
9.76 (m, 1 H). 13C NMR (100 MHz, CDCl3): δ = 21.43,
21.65, 24.95, 28.45, 28.52, 28.67, 43.58, 70.38, 127.67,
129.66, 132.96, 144.54, 202.50. ESI-HMRS: m/z calcd for
C15H23O4S [M + H]: 299.1312; found: 299.1310.
2.18–2.28 (m, 2 H), 2.61–2.73 (m, 2 H), 4.10–4.17 (m, 1 H).
13C NMR (100 MHz, CDCl3): δ = –5.39, 17.53, 25.24,
33.65, 36.38, 65.39, 211.26. HMRS (APPI): m/z calcd for
C12H25O2Si [M + H]: 229.1618; found: 229.1617.
2,3,4,6-Tetra-O-benzyl-D-glucono-1,5-lactone (2r): oil.
IR (neat): 2919, 2869, 1755, 1454, 1165, 1094, 738, 698
cm–1. 1H NMR (400 MHz, CDCl3): δ = 3.64–3.75 (m, 2 H),
3.88–3.98 (m, 2 H), 4.12 (d, J = 6.1 Hz, 1 H), 4.43–4.76 (m,
8 H), 4.98 (d, J = 11.3 Hz, 1 H), 7.15–7.41 (m, 20 H). 13
C
NMR (100 MHz, CDCl3): δ = 68.21, 73.52, 73.69 (2 C),
73.91, 76.01, 78.12, 80.92, 127.79 (3 C), 127.91, 127.96 (3
C), 128.08, 128.37, 128.41 (2 C), 128.45, 136.90, 137.46 (2
C), 137.55, 169.31. ESI-HMRS: m/z calcd for C34H35O6
[M + H]: 539.2428; found: 539.2423.
4-[(tert-Butyldimethylsilyl)oxy]cyclohexanone (2p): oil
(commercial, oil). IR (neat): 1720 cm–1. 1H NMR (400 MHz,
CDCl3): δ = 0.10 (s, 6 H), 0.92 (s, 9 H), 1.83–2.02 (m, 4 H),
(11) Pelletier, G.; Bechara, W. S.; Charette, A. B. J. Am. Chem.
Soc. 2010, 132, 12817.
Synlett 2012, 23, 1250–1256
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