Iodoarene-mediated α-tosyloxylation of ketones with MCPBA and p-toluenesulfonic acid

Article abstract of DOI:10.1055/s-0030-1260948

Alkyl aryl ketones and dialkyl ketones could be converted into the corresponding α-tosyloxy ketones by the reaction with MCPBA and p-toluenesulfonic acid monohydrate (PTSA ? H₂O) in the presence of a catalytic amount of molecular iodine (I

Full text of DOI:10.1055/s-0030-1260948

LETTER
1853
Iodoarene-Mediated a-Tosyloxylation of Ketones with MCPBA and
p-Toluenesulfonic Acid
I
odoarene-Mediate
y
d
a
-Tosylox
u
ylation of
K
e
m
tones i Tanaka, Katsuhiko Moriyama, 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 18 April 2011
arenes with sulfonic acids and MCPBA.4 Based on these
results, the PhI-catalyzed, polymer-supported PhI-cata-
lyzed, and ion-supported PhI-catalyzed a-tosyloxylation
of ketones with MCPBA and p-toluenesulfonic acid
Abstract: Alkyl aryl ketones and dialkyl ketones could be convert-
ed into the corresponding a-tosyloxy ketones by the reaction with
MCPBA and p-toluenesulfonic acid monohydrate (PTSA·H2O) in
the presence of a catalytic amount of molecular iodine (I2) in a mix-
ture of acetonitrile and 2,2,2-trifluoroethanol, although the yields monohydrate;5a–c the PhI-catalyzed and ion-supported
were dependent on the ketones (method A). The same conversion of
PhI-catalyzed preparation of 3,4-dihydro-1H-2,1-ben-
alkyl aryl ketones and dialkyl ketones into the corresponding a-
zothiazine 2,2-dioxides from N-methoxy-2-arylethane-
tosyloxy ketones could be smoothly carried out by the reaction with
sulfonamides with MCPBA,5d–f the PhI-catalyzed
MCPBA and PTSA·H2O in the presence of catalytic amounts of
preparation of oxazoles with MCPBA5g or Oxone®,5h and
iodine and tert-butylbenzene in a mixture of acetonitrile and 2,2,2-
the PhI-catalyzed a-tosyloxylation of ketones with Ox-
one® and p-toluenesulfonic acid monohydrate5i were car-
ried out. Among those reactions, the ArI-catalyzed
oxidative conversion of substrates with MCPBA is very
attractive as MCPBA is a rather strong nonmetal oxidant
and the formed m-chlorobenzoic acid (MCBA) can be re-
moved easily by extraction with an aqueous basic solu-
tion. Here, as part of our study on the use of molecular
iodine (I2) for organic synthesis6 and ArI-catalyzed organ-
ic reactions,5 we would like to report the iodoarene-medi-
ated a-tosyloxylation of ketones with MCPBA and p-
toluenesulfonic acid monohydrate both in the absence and
in the presence of tert-butylbenzene in a mixture of aceto-
nitrile and 2,2,2-trifluoroethanol.
trifluoroethanol (method B). In those reactions, p-iodotoluene and
4-tert-butyl-1-iodobenzene were formed at first in method A and
method B, respectively, and then they were converted into p-[(hy-
droxy)(tosyloxy)]iodotoluene and 4-tert-butyl-1-[(hydroxy)(tosyl-
oxy)iodo]benzene by the reaction with MCPBA and PTSA·H2O. p-
[(Hydroxy)(tosyloxy)]iodotoluene and 4-tert-butyl-1-[(hydroxy)-
(tosyloxy)iodo]benzene worked as an a-tosyloxylation reagent of
ketones.
Key words: molecular iodine, tert-butylbenzene, MCPBA, a-tosyl-
oxy ketone, ketone, p-toluenesulfonic acid, catalyst
a-Tosyloxy ketones are very important strategic precur-
sors for the construction of various heteroaromatics, such
as thiazoles, imidazoles, imidazo[1,2-a]pyridines, ox-
azoles, selenazoles, pyrazoles, and benzofurans.1 [(Hy-
droxy)(tosyloxy)iodo]benzene (HTIB) is the sole reagent
for the direct a-tosyloxylation of ketones. Generally,
HTIB is prepared via two steps: the initial oxidation of io-
dobenzene to (diacetoxyiodo)benzene, followed by the
treatment with p-toluenesulfonic acid monohydrate.1a,b
We have studied the synthetic uses of [(hydroxy)(tosyl-
oxy)iodo]arenes, 1-(arenesulfonyloxy)benziodoxolones,
and poly[4-(hydroxy)(tosyloxy)iodo]styrenes for the a-
tosyloxylation of ketones and the construction of thiaz-
oles, imidazoles, and imidazo[1,2-a]pyridines.2 On the
other hand, the ArI-catalyzed oxidative conversion of sub-
strates, such as ketones, hydroquinones, alkenes, alcohols,
and amides, with m-chloroperbenzoic acid (MCPBA) or
Oxone® has become very popular3 because it is a metal-
free oxidative reaction and hypervalent iodines are
formed in situ. In this regard, environmentally benign or-
ganic synthesis may be carried out. Previously, we report-
ed an efficient method for the preparation of various
[(hydroxy)(sulfonyloxy)iodo]arenes directly from iodo-
At first, iodine, p-toluenesulfonic acid monohydrate, and
MCPBA were dissolved in a mixture of acetonitrile and
2,2,2-trifluoroethanol. The resulting solution was stirred
at room temperature until the color of iodine faded com-
pletely. Then, a solution of acetophenone in acetonitrile
was added to the resulting solution, and the mixture was
stirred for three hours at 60 °C to give a-tosyloxyace-
tophenone in 71% yield as shown in Table 1 (entry 1,
method A).7 a-Tosyloxyacetophenone was not obtained at
all in the absence of iodine (entry 3, method A). When the
reaction was carried out in acetonitrile alone, the yield of
a-tosyloxyacetophenone was low (entry 2, method A). On
the other hand, the addition of 2,2,2-trifluoroethanol as
co-solvent enhanced the reaction to provide a-tosyloxyac-
etophenone in good yield. Moreover, the yield of a-tosyl-
oxyacetophenone was low when Oxone®, instead of
MCPBA as an oxidant, was used under the same condi-
tions (entry 4, method A). Today, it is well known that
2,2,2-trifluoroethanol promotes the oxidative reactions
with hypervalent iodines8,9 and therefore, the promotion
of the oxidative a-tosyloxylation of acetophenone was ob-
served in the present reaction. In further detailed studies,
it became clear that p-iodotoluene was formed at first
in the present reaction, and it was further oxidized to
p-[(hydroxy)(tosyloxy)iodo]toluene by the reaction with
SYNLETT 2011, No. 13, pp 1853–1858
x
x
.x
x
.2
0
1
1
Advanced online publication: 14.07.2011
DOI: 10.1055/s-0030-1260948; Art ID: U03711ST
© Georg Thieme Verlag Stuttgart · New York

1854
A.Tanaka et al.
LETTER
MCPBA and p-toluenesulfonic acid monohydrate. Practi- depending on the ketones. On the whole, the yields of
cally, the treatment of p-toluenesulfonic acid monohy- a-tosyloxy ketones with alkyl aryl ketones bearing an
drate (2.1 mmol) and MCPBA (2.2 mmol) in the presence electron-donating group on the aromatic ring were low,
of molecular iodine (2.4 mmol) in a mixture of acetonitrile and those of dialkyl ketones were likewise low. The re-
(3 mL) and 2,2,2-trifluoroethanol (3 mL) at 60 °C for five sults suggest that the smooth formation of the enol form is
hours provided 4-iodotoluene in 54% yield.10 On the other important. However, the nucleophilicity of the enol form
hand, when the a-sulfonyloxylation of acetophene (1.0 of b-keto esters is not sufficiently high due to the presence
mmol) with MCPBA (2.2 mmol) and molecular iodine of an ester group (entries 15, 16).
(0.1 mmol) in the presence of camphorsulfonic acid (2.1
mmol), an aliphatic sulfonic acid, was carried out at 60 °C
for 24 hours under the same conditions, only trace amount
of a-camphorsulfonyloxyacetophenone was obtained.
Thus, the present reaction requires aromatic sulfonic ac-
ids, not aliphatic sulfonic acids. Once p-iodotoluene is
formed, it is easily oxidized to p-[(hydroxy)(tosyloxy)io-
Table 1 Preparation of a-Tosyloxy Ketones from Ketones with
Methods A and B
Method A: I2 (0.1 equiv), MCPBA (2.2 equiv),
p-TsOH⋅H2O (2.1 equiv)
Method B: I2 (0.1 equiv), t-BuPh (0.2 equiv),
MCPBA (1.7 equiv), p-TsOH⋅H2O
(1.5 equiv)
O
do]toluene by the reaction with MCPBA and p-toluene-
1) MeCN–CF3CH2OH (1:1), r.t.
R2
OTs
sulfonic acid monohydrate at room temperature.4 Thus,
the real key species in method A is p-[(hydroxy)(tosyl-
oxy)iodo]toluene. Based on these results, the a-tosyloxyl-
ation of various ketones, such as alkyl aryl ketones and
dialkyl ketones, with MCPBA and p-toluenesulfonic acid
monohydrate in the presence of iodine in a mixture of
acetonitrile and 2,2,2-trifluoroethanol (method A) was
carried out to provide the corresponding a-tosyloxy ke-
tones in good yields (entries 6–10), moderate yields (en-
tries 5, 11, 15, 16), and low yields (entries 12–14, 17, 18),
Method A or
Method B
R1
2)
R1
O
60 °C, time
R2
Entry Producta
Method A
Method B
Time Yield Time Yield
(h)
(%)
(h)
(%)
O
1
2
3
4
3
71
35
0
5
16b
5c
70
55
0
8b
5c
5c
OTs
O
34
5d
41
OH
O
R2
R2
TsO
R1
R1
5
10
43
71
4
6
66
75
OTs
O
H2O
R2
O
R1
O
R2
OTs
6
5
R1
I
R3
OTs
OH2
Cl
O
(I)
7
4
7
90
85
5
5
96
95
OH
I
OTs
R3
I
O2N
R3
O
OTs
8
OTs
OTs
R = Me, t-Bu
NO2
O
O
9
7.5
16
69
65
5
4
71
80
MCBA
MCPBA
TsOH⋅H2O
10
(Method A)
Me
6
I2, MCPBA
SO3H
OTs
O
I
Me
(Method B)
t-Bu
11
72
42
72
64
I2, MCPBA
I
t-Bu
OTs
Scheme 1 Reaction mechanism for iodoarene-mediated a-tosyl-
oxylation of ketones (methods A and B)
Synlett 2011, No. 13, 1853–1858 © Thieme Stuttgart · New York

LETTER
Iodoarene-Mediated a-Tosyloxylation of Ketones
1855
Table 1 Preparation of a-Tosyloxy Ketones from Ketones with
zene in a mixture of acetonitrile and 2,2,2-trifluoroetha-
nol. We noted improvements in the yields of a-tosyloxy
ketones. In this case, 4-tert-butyl-1-iodobenzene was
formed at first, and then 4-tert-butyl-1-[(hydroxy)(tosyl-
oxy)iodo]benzene was generated from the reaction of 4-
tert-butyl-1-iodobenzene with MCPBA and p-toluene-
sulfonic acid monohydrate,4 and worked as an a-tosylox-
ylating reagent of ketones, similar to HTIB. Here, we do
not have to use expensive iodoarenes and it is formed in
situ and works as a catalyst. Thus, to a stirred solution of
tert-butylbenzene in a mixture of acetonitrile and 2,2,2-
trifluoroethanol were added MCPBA, iodine, and p-tolu-
enesulfonic acid monohydrate. The resulting solution was
stirred at room temperature until color of iodine faded
completely. Then, a solution of acetophenone in acetoni-
trile was added to the resulting solution, and the mixture
was stirred for five hours at 60 °C to provide a-tosyloxy-
acetophenone in 70% yield (entry 1, method B).7 When
anisole, benzene, and toluene instead of tert-butylbenzene
was used for the a-tosyloxylation of acetophenone with
MCPBA, iodine, and p-toluenesulfonic acid monohydrate
under the same conditions, a-tosyloxyacetophenone was
obtained in 48%, 45%, and 64% yields, respectively.
Thus, tert-butylbenzene is the most effective among ani-
sole, benzene, toluene, and tert-butylbenzene. In the reac-
tion with acetophenone, the additive effect of tert-
butylbenzene was not observed at all (entry 1, method A
and B). However, a-tosyloxyacetophenone was not ob-
tained at all in the absence of iodine (entry 3, method B).
In other alkyl aryl ketones and dialkyl ketones under the
same conditions, the corresponding a-tosyloxy ketones
were obtained in good to moderate yields (entries 5–19,
method B), and overall, the yields with method B were
higher than those with method A. The plausible reaction
mechanism, which is the same as that with HTIB, is
shown in Scheme 1. Thus, p-iodotoluene is formed at first
via the desulfonyloxyiodonation of p-toluenesulfonic acid
by the reaction with MCPBA and molecular iodine in
method A.10 On the other hand, 4-tert-butyl-1-iodoben-
zene is formed by the reaction of tert-butylbenzene with
MCPBA and molecular iodine in method B.9 Once p-io-
dotoluene and 4-tert-butyl-1-iodobenzene are formed, p-
[(hydroxy)(tosyloxy)iodo]toluene and 4-tert-butyl-1-
[(hydroxy)(tosyloxy)iodo]benzene are generated in meth-
od A and method B, respectively, as the a-tosyloxylation
reagent of ketones. a-Tosyloxy ketones are produced via
intermediate I by the reaction of ketones with p-[(hy-
droxy)(tosyloxy)iodo]toluene and 4-tert-butyl-1-[(hy-
droxy)(tosyloxy)iodo]benzene, like HTIB1a
Methods A and B (continued)
Method A: I2 (0.1 equiv), MCPBA (2.2 equiv),
p-TsOH⋅H2O (2.1 equiv)
Method B: I2 (0.1 equiv), t-BuPh (0.2 equiv),
MCPBA (1.7 equiv), p-TsOH⋅H2O
(1.5 equiv)
O
1) MeCN–CF3CH2OH (1:1), r.t.
R2
OTs
Method A or
Method B
R1
2)
R1
O
60 °C, time
R2
Entry Producta
Method A
Method B
Time Yield Time Yield
(h)
20
(%)
21
(h)
5
(%)
58
O
12
OTs
O
O
S
13
14
30
24
11
21
3
5
47
49
OTs
OTs
O
O
O
15
3
43
3
63
OEt
OTs
O
O
16
17
18
19
2
1
41
31
14
54
2.5
60
62
57
68
OMe
OTs
O
3
OTs
O
21
5
6
OTs
O
2.5
γ
α
(TsO)
(OTs)
(a/g = 1:9.8)
(a/g = 1:8.7)
a Isolated yield.
b Only MeCN was used as a solvent.
c Reaction was carried out without I2.
d Oxone® was used instead of MCPBA.
In conclusion, alkyl aryl ketones and dialkyl ketones
could be converted into the corresponding a-tosyloxy ke-
tones by the reaction with MCPBA and p-toluenesulfonic
acid monohydrate in the presence of a catalytic amount of
iodine in a mixture of acetonitrile and 2,2,2-trifluoroetha-
nol, and the yields were dependent on the ketones used.
The same a-tosyloxylation of alkyl aryl ketones and di-
alkyl ketones occurred smoothly by the reaction with
MCPBA and p-toluenesulfonic acid monohydrate in the
This may be the reason why the yield with b-keto esters is
not so high. Recently, a one-pot preparation of [(hy-
droxy)(tosyloxy)iodo]arenes from arenes with iodine,
p-toluenesulfonic acid monohydrate, and MCPBA was
reported.9 Based on that report and our previous report,4
we next studied the a-tosyloxylation of ketones with
MCPBA and p-toluenesulfonic acid monohydrate in the
presence of catalytic amounts of iodine and tert-butylben-
Synlett 2011, No. 13, 1853–1858 © Thieme Stuttgart · New York

1856
A.Tanaka et al.
LETTER
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zene in a mixture of acetonitrile and 2,2,2-trifluoroetha-
nol. Both a-tosyloxylation reactions of ketones proceeded
via the formation of [(hydroxy)(tosyloxy)iodo]arenes in
situ and did not require expensive iodoarenes. Further
synthetic study of the present reaction is under way in this
laboratory.
Acknowledgement
Financial support in the form of a Grant-in-Aid for Scientific Re-
search (No. 20550033) from the Ministry of Education, Culture,
Sports, Science, and Technology in Japan, Iodine Research Project
in Chiba University, Academia Showcase Research Grant from the
Japan Chemical Innovation Institute (JCII), and Futaba Electronics
Memorial Foundation is gratefully acknowledged.
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Method A
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I2 (0.1 mmol), p-TsOH·H2O (2.1 mmol), and MCPBA (2.2
mmol) were dissolved in a mixture of MeCN (3 mL) and
2,2,2-trifluoroethanol (3 mL) under argon atmosphere. The
resulting solution was stirred at r.t. until the color of I2 faded
completely (1–2 h). Then, a solution of acetophenone (1
mmol) in MeCN (2 mL) was added, and the mixture was
stirred for 3 h at 60 °C under argon atmosphere. After the
reaction, the reaction mixture was poured into a solution of
sat. aq NaHCO3 and Na2SO3, and the whole was extracted
with CHCl3 (3 × 20 mL). The organic layer was dried over
Na2SO4. After removal of the solvent under reduced
pressure, a-tosyloxyacetophenone was obtained in the crude
Synlett 2011, No. 13, 1853–1858 © Thieme Stuttgart · New York

LETTER
Iodoarene-Mediated a-Tosyloxylation of Ketones
1857
state. Pure a-tosyloxyacetophenone was obtained in 71%
133.93, 143.48, 143.69, 145.10, 194.93.
a-(Tosyloxy)octyl Phenyl Ketone
yield (206 mg) by short flash column chromatography on
silica gel (EtOAc–hexane = 1:3).
Mp 59–61 °C (lit.2d mp 59–61 °C). IR (neat): 1180, 1340,
1700 cm–1. 1H NMR (400 MHz, CDCl3): d = 0.86 (t, J = 6.9
Hz, 3 H), 1.20–1.43 (m, 10 H), 1.84–1.91 (m, 2 H), 2.40 (s,
3 H), 5.59 (dd, J = 8.2, 4.8 Hz, 1 H), 7.24 (d, J = 8.0 Hz, 2
H), 7.45 (t, J = 7.5 Hz, 2 H), 7.59 (t, J = 7.5 Hz, 1 H), 7.74
(d, J = 8.2 Hz, 2 H), 7.86 (d, J = 8.2 Hz, 2 H).
Method B
To a stirred solution of tert-butylbenzene (0.2 mmol) in a
mixture of MeCN (3 mL) and 2,2,2-trifluoroethanol (3 mL)
under argon atmosphere were added MCPBA (1.7 mmol),
I2 (0.1 mmol), and p-TsOH·H2O (1.5 mmol). The resulting
solution was stirred at r.t. until the color of I2 faded
completely (1–2 h). Then, a solution of acetophenone (1
mmol) in MeCN (2 mL) was added, and the mixture was
stirred for 5 h at 60 °C under argon atmosphere. After the
reaction, the reaction mixture was poured into a solution of
sat. aq NaHCO3 and Na2SO3, and the whole was extracted
with CHCl3 (3 × 20 mL). The organic layer was dried over
Na2SO4. After removal of solvent under reduced pressure, a-
tosyloxyacetophenone was obtained in the crude state. Pure
a-tosyloxyacetophenone was obtained in 70% yield (204
mg) by short flash column chromatography on silica gel
(EtOAc–hexane = 1:3).
Tosyloxymethyl Naphthyl Ketone
Oil (lit.12). IR (neat): 1176, 1365, 1700 cm–1. 1H NMR (400
MHz, CDCl3): d = 2.40 (s, 3 H), 5.27 (s, 2 H), 7.29 (d, J = 8.4
Hz, 2 H), 7.50 (t, J = 8.3 Hz, 1 H), 7.53–7.60 (m, 2 H), 7.78
(dd, J = 1.2, 7.4 Hz, 1 H), 7.81 (d, J = 8.3 Hz, 2 H), 7.87 (d,
J = 7.8 Hz, 1 H), 8.04 (d, J = 8.3 Hz, 1 H), 8.48 (dd, J = 0.9,
8.3 Hz, 1 H). 13C NMR (100 MHz, CDCl3): d = 21.65, 70.99,
124.13, 125.35, 126.82, 128.08, 128.34, 128.44, 128.50,
129.87, 130.16, 131.28, 132.60, 133.91, 134.05, 145.24,
193.91.
2,4,6-Trimethylphenyl (Tosyloxy)methyl Ketone
Mp 58 °C. IR (neat): 1191, 1377, 1608 cm–1. 1H NMR (400
MHz, CDCl3): d = 2.12 (s, 6 H), 2.27 (s, 3 H), 2.45 (s, 3 H),
4.84 (s, 2 H), 6.81 (s, 2 H), 7.33 (d, J = 8.0 Hz, 2 H), 7.87 (d,
J = 8.0 Hz, 2 H). 13C NMR (100 MHz, CDCl3): d = 18.96,
21.08, 21.65, 72.28, 128.05, 128.61, 129.81, 132.70, 133.83,
134.70, 139.82, 145.19, 201.17. ESI-HRMS: m/z calcd for
C18H21O4SNa [M + Na]: 355.0980; found: 355.0946.
2-Furyl (Tosyloxy)methyl Ketone
a-Tosyloxyacetophenone
Mp 90 °C (lit.1h mp 90–91 °C). IR (KBr): 1180, 1360, 1715
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). 13C NMR (100 MHz, CDCl3): d = 21.67, 69.90,
127.97, 128.13, 128.89, 129.89, 132.57, 133.71, 134.19,
145.28, 190.26.
Mp 63–64 °C (lit.1h mp 65–67 °C). IR (KBr): 1695, 1370,
1170, 810, 750 cm–1. 1H NMR (400 MHz, CDCl3): d = 2.45
(s, 3 H), 5.09 (s, 2 H), 6.58 (dd, J = 3.7, 1.7 Hz, 1 H), 7.33
(dd, J = 3.7, 0.7 Hz, 1 H), 7.36 (d, J = 8.2 Hz, 2 H), 7.61 (dd,
J = 1.7, 0.7 Hz, 1 H), 7.86 (d, J = 8.2 Hz, 2 H).
a-Tosyloxy-p-methylacetophenone
Mp 105 °C (lit.11 mp 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).
13C NMR (100 MHz, CDCl3): d = 21.68, 21.77, 69.85,
128.07, 128.14, 129.57, 129.87, 131.24, 132.62, 145.23,
145.28, 189.80.
2-Thienyl (Tosyloxy)methyl Ketone
Mp 92–93 °C (lit.1i mp 94–96 °C). IR (KBr): 1685, 1370,
1180, 730 cm–1. 1H NMR (400 MHz, CDCl3): d = 2.45 (s,
3 H), 5.09 (s, 2 H), 7.16 (dd, J = 5.0, 3.9 Hz, 1 H), 7.35 (d,
J = 8.1 Hz, 2 H), 7.73 (dd, J = 5.0, 1.0 Hz, 1 H), 7.79 (dd,
J = 3.9, 1.0 Hz, 1 H), 7.85 (d, J = 8.1 Hz, 2 H). 13C NMR
(100 MHz, CDCl3): d = 21.66, 69.87, 128.17, 128.46,
129.94, 132.38, 133.13, 135.12, 140.12, 145.43, 183.64.
Ethyl a-Tosyloxybenzoylacetate
a-Tosyloxy-p-chloroacetophenone
Mp 123 °C (lit.11 mp 125 °C). IR (KBr): 1190, 1360, 1710
cm–1. 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). 13C NMR (100
MHz, CDCl3): d = 21.71, 69.79, 128.14, 129.28, 129.48,
129.94, 132.05, 132.44, 140.78, 145.43, 189.55.
a-Tosyloxy-p-nitroacetophenone
Oil. IR (neat): 1440, 1590, 1690 cm–1. 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.
HRMS–FAB: m/z calcd for C18H19O6S [M + 1]: 363.0902;
found: 363.0920.
Mp 137 °C (lit.11 mp 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). 13
C
NMR (100 MHz, CDCl3): d = 21.83, 70.04, 117.70, 124.17,
128.26, 129.45, 130.15, 132.32, 138.29, 145.81, 189.87.
a-Tosyloxy-m-nitroacetophenone
Methyl a-Tosyloxyacetoacetate
Mp 129–130 °C. IR (KBr): 1615, 1375, 1348, 1188 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). 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. ESI-HRMS: m/z calcd for C15H13O6NSNa [M + Na]:
358.0356; found: 358.0347.
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 calcd for C12H15O6S [M + 1]: 287.0589;
found: 287.0596.
2-Tosyloxy-3-pentanone
Mp 45–46 °C (lit.1k mp 43–44 °C). IR (neat): 1190, 1360,
1720 cm–1. 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). 13C NMR (100 MHz, CDCl3): d = 6.96,
17.58, 21.65, 31.16, 80.68, 127.85, 129.99, 133.16, 145.29,
207.81.
a-Tosyloxypropiophenone
Mp 68 °C (lit.11 mp 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). 13C NMR (100 MHz, CDCl3):
d = 18.84, 21.74, 128.04, 128.84, 129.85, 133.51, 133.77,
Synlett 2011, No. 13, 1853–1858 © Thieme Stuttgart · New York

1858
A.Tanaka et al.
LETTER
5-Tosyloxy-6-undecanone
(dd, J = 8.4, 4.6 Hz, 1 H), 7.36 (d, J = 8.7 Hz, 2 H), 7.81 (d,
J = 8.7 Hz, 2 H). 13C NMR (100 MHz, CDCl3): d = 13.91,
21.97, 22.35, 24.17, 26.01, 31.00, 31.52, 84.62, 128.13,
130.07, 132.98, 145.48, 205.78. HRMS–FAB: m/z calcd for
C15H23O4S [M + 1]: 299.1317; found: 299.1315.
(8) (a) Dohi, T.; Maruyama, A.; Minamitsuji, Y.; Takenaga, N.;
Kita, Y. Chem. Commun. 2007, 1224. (b) Dohi, T.; Ito, M.;
Morimoto, K.; Minamitsuji, Y.; Takenaga, N.; Kita, Y.
Chem. Commun. 2007, 4152. (c) Dohi, T.; Ito, M.;
Yamaoka, N.; Morimoto, K.; Fujioka, H.; Kita, Y.
Tetrahedron 2009, 65, 10797.
(9) Merritt, E. A.; Carneiro, V. M. T.; Silva, L. F. Jr.; Olofsson,
B. J. Org. Chem. 2010, 75, 7416.
(10) Suzuki, Y.; Moriyama, K.; Togo, H. Tetrahedron Lett. 2010,
51, 5950.
(11) Khanna, M. S.; Grag, C. P.; Kapoor, R. P. Tetrahedron Lett.
1992, 33, 1495.
(12) Cho, B. T.; Choi, O. K. Bull. Korean Chem. Soc. 2001, 22,
Mp 72 °C (lit.2d mp 72 °C). 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).
1-Tosyloxy-2-octanone
Oil. IR (neat): 1180, 1360, 1590, 1730 cm–1. 1H NMR (400
MHz, CDCl3): d = 0.87 (t, J = 7.0 Hz, 3 H), 1.20–1.32 (m, 6
H), 1.48–1.62 (m, 2 H), 2.45 (s, 3 H), 2.49 (t, J = 7.2 Hz, 2
H), 4.49 (s, 2 H), 7.37 (d, J = 8.0 Hz, 2 H), 7.82 (d, J = 8.0
Hz, 2 H). 13C NMR (100 MHz, CDCl3): d = 13.97, 21.68,
22.39, 22.76, 28.62, 31.43, 38.98, 71.78, 128.04, 130.00,
132.30, 145.44, 203.43. HRMS–FAB: m/z calcd for
C15H23O4S [M + 1]: 299.1317; found: 299.1295.
3-Tosyloxy-2-octanone
Oil. IR (neat): 1180, 1360, 1600, 1740 cm–1. 1H NMR (400
MHz, CDCl3): d = 0.80 (t, J = 7.3 Hz, 3 H), 1.00–1.30 (m,
6 H), 1.54–1.78 (m, 2 H), 2.23 (s, 3 H), 2.48 (s, 3 H), 4.58
444.
Synlett 2011, No. 13, 1853–1858 © Thieme Stuttgart · New York