A novel and convenient approach for tosyloxylation of aromatic ring of some ortho-substituted phenolic compounds using [hydroxy(tosyloxy)iodo]benzene

Article abstract of DOI:10.1016/j.tet.2010.05.042

The oxidation of some substituted monohydric phenols, containing electron-withdrawing substituents at the ortho position to the phenolic group, with [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser's reagent) leads to novel tosyloxylation of aromatic ring, the

Full text of DOI:10.1016/j.tet.2010.05.042

Tetrahedron 66 (2010) 5827e5832
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Tetrahedron
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A novel and convenient approach for tosyloxylation of aromatic ring of some
ortho-substituted phenolic compounds using [hydroxy(tosyloxy)iodo]benzene
,
a
b
Om Prakash a , Manoj Kumar , Rajesh Kumar
*
a Department of Chemistry, Kurukshetra University, Kurukshetra-136119, Haryana, India
b Post Graduate Department of Chemistry, M. L. N. College, Yamuna Nagar-135001, Haryana, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 15 April 2010
Received in revised form 10 May 2010
Accepted 13 May 2010
Available online 1 June 2010
The oxidation of some substituted monohydric phenols, containing electron-withdrawing substituents at
the ortho position to the phenolic group, with [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser’s reagent)
leads to novel tosyloxylation of aromatic ring, thereby offering a convenient synthesis of hitherto un-
known 4-tosyloxy-2-substituted phenols.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Hypervalent iodine reagents
[Hydroxy(tosyloxy)iodo]benzene
Substituted phenols
Tosyloxylation
1. Introduction
Ph
X
I
The oxidation of phenols is a key biochemical process in
oxidative phosphorylation and it is also important in numerous
biosynthetic pathways.1 There has been considerable interest in
developing controlled synthetic transformations involving oxi-
dation of phenolic compounds with a variety of oxidants. Useful
reagents include Fermy’s salt2 and a wide variety of other redox-
metal based oxidants such as Pb(IV),3 Tl(III),4 Mn(III),5 Cu(II),6 and
Fe(III).7 Recently, the use of hypervalent iodine reagents has
offered very interesting and useful transformations from various
phenolic compounds.8 The beneficial features for the use of
hypervalent iodine reagents9 are their low toxicity, high stability,
easy handling, and unique reactivity similar to that of a series of
heavy metals. Extensive research studies reported to date in the
literature reveal that the process that occurs during the oxidation
of phenolic compounds with hypervalent iodine reagents can be
divided in two categories. The first category involves ligand
exchange of the phenolic proton with the hypervalent iodine re-
agent to generate the OeI(III) intermediate, which is subsequently
transformed to various products, depending upon the reaction
conditions (Eq. 1).
O
OH
PhIX2
(1)
Products
+
PhI
Z
Z
These transformations include oxidation of phenols to qui-
nones and related compounds,10 formation of spirocyclic
compounds,11 oxygen heterocyclic compounds via oxidative
intramolecular participation reactions,12 and intramolecular
carbonecarbon bond formation via phenolic oxidative coupling.13
All of these reactions are driven by the reduction of iodine (III) to
iodine (I).
The second category of these reactions includes formation of
stable iodonium salts and ylides, which are important in-
termediates in organic synthesis. These reactions occur via car-
boneI (III) bond formation without loss of iodobenzene (Eq. 2).14
Z
O-
Z
OH
Z
OH
(2)
* Corresponding author. Tel.: þ91 1744 238410; fax: þ91 1744 238277; e-mail
addresses: dromprakash50@rediffmail.com (O. Prakash), rajeshchem12a@gmail.
com (R. Kumar).
I+PhX-
I+PhX-
Y
Y
Y
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.05.042

5828
O. Prakash et al. / Tetrahedron 66 (2010) 5827e5832
Of the various hypervalent iodine reagents employed for phe-
spectral (IR, 1H NMR) and elemental analytical data (Scheme 1).
This was a novel observation, as no such an example of tosyloxy-
lation of phenolic compounds is known in the literature.
nolic oxidations, organoiodine(III) reagents namely, iodobenzene
diacetate (IBD) and iodobenzene bis(trifluoroacetate) (IBTA) have
found versatile and significant applications. In contrast, [hydroxy
(tosyloxy)iodo]benzene (HTIB), which is well known for its versatile
synthetic utility, particularly tosyloxylation of olefinic and carbonyl
compounds,15 has little been explored for phenolic oxidations.
Previous investigations from our laboratory have shown that
oxidation of some dihydroxy phenols containing enolizable moiety
at the o-position of phenolic group leads to regioselective oxy-
genation of aromatic ring16 and formation of iodonium ylides and
their rearrangement17depending upon the nature of substrate and
reaction condition as outlined in Eqs. 3 and 4, respectively.
OH
OH
PhI(OH)OTs, CH2Cl2
rt
CH3
CH3
TsO
O
O
2a
1a
Scheme 1. Reaction of o-hydroxyacetophenone (1a) with HTIB in dichloromethane.
Further, it is worthwhile to mention that o-hydroxy-
acetophenone on treatment with IBDeKOH in methanol is known
to give 2,2-dimethoxycoumaran-3-one (Eq. 7).12b We attempted
this reaction using IBD in methanol and dichloromethane in the
absence of KOH. However, in this experiment only starting
o-hydroxyacetophenone was recovered.
OH
OH
IBD, ROH
(3)
CH3
CH3
HO
HO
O
OR
O
OH
O
OMe
OMe
IBD
I
CH3
(7)
KOH, MeOH
PhO
OH
HO
X
OH
IBD-KOH
MeOH
(4)
O
O
X
R
R
Encouraged by this result on tosyloxylation of 1a, we became
interested in examining the impact of the structure of phenolic
compounds on the reaction outcome. Accordingly variously
substituted monohydric phenols 1beq were subjected to reaction
with HTIB under similar conditions. The results summarized in
Table 1, clearly indicate that the reaction is greatly influenced by the
electronic effect and position of substituents on the aromatic ring of
monohydric phenols. The results of this study are discussed
according to the type of phenolic substrates employed.
O
O
When applied to 6-hydroxyflavone and 6-hydroxyflavanone,
the oxidative approach using IBD in acetic acid provides a conve-
nient route for the synthesis of 5-acetoxylated products (Eqs. 5
and 6).18
O
Ph
O
Ph
PhI(OAc)2
AcOH
(5)
2.1. Phenols containing electron-withdrawing substituents at
the ortho position
HO
HO
O
OAc
O
The monohydric phenols, which contain electron-withdrawing
substituents (eNO2, eCHO, eCONH2, eCOOCH3, eCOOPh) at the or-
tho position on treatment with 1.1 equiv of HTIB in dichloromethane
underwent smooth tosyloxylation to the corresponding 4-tosyloxy-
2-substituted phenols (2bef) (Scheme 2, Table 1, entries 2e6).20
Obviously, in all these cases, tosyloxylation occurred at the
vacant para position with respect to the phenolic hydroxyl group.
The reaction of 2-acetyl-4-methylphenol (1g), where para position
was occupied by methyl group occurred according to expectation to
give the ortho substituted product 2g in 78% yield (Table 1, entry 7).
In case of 1-formyl-2-naphthol (1h) tosyloxylation occurred at
6-position to give 1-formyl-6-tosyloxy-2-naphthol (2h) in 72%
yield (Table 1, entry 8).
O
Ar
O
Ar
PhI(OAc)2
AcOH
(6)
HO
HO
O
OAc
O
Encouraged by our previous results and keeping in view that the
use of HTIB for oxidation of monohydric phenolic compounds,
particularly which contain electron-withdrawing groups has not
been explored till date,19 we have now investigated the oxidation of
some substituted monohydric phenols 1 with emphasis on those
containing electron-withdrawing substituents (eNO2, eCHO,
eCONH2, eCOOCH3, eCOOPh) at ortho position with HTIB in
dichloromethane. The study has led to a novel tosyloxylation of
aromatic ring of substituted monohydric phenols 1, thereby offer-
ing a convenient synthesis of hitherto unknown 4-tosyloxy-2-
substituted phenols (2).
2.2. Phenol and phenols containing electron-releasing
substituents at the ortho position
The phenols, which contain electron-releasing substituents
such as CH3 and OCH3 at the ortho position did not give the tosy-
loxylated product under the same conditions (Table 1, entries 9 and
10). The reaction was sluggish and formation of complex mixture
was observed. Despite making numerous attempts, we were unable
to isolate corresponding 4-tosyloxy-2-substituted phenols. The
reaction of parent phenol with HTIB also did not give any successful
result (Table 1, entry 17). Monitoring the reaction by 1H NMR did
not give any indication of tosyloxylation of aromatic ring.
2. Results and discussion
We first selected o-hydroxyacetophenone (1a), which was
treated with 1.1 equiv of HTIB in dichloromethane at room tem-
perature for 3 h. The single product isolated from this reaction was
characterized as 2-acetyl-4-tosyloxyphenol (2a) on the basis of

O. Prakash et al. / Tetrahedron 66 (2010) 5827e5832
Table 1 (continued)
5829
Table 1
Products of the reactions of substituted monohydric phenols with HTIB in di-
chloromethane at room temperature
Entry
Substrates
Productsa
Yieldb (%)
Productsa
Yieldb (%)
OH
Entry
1
Substrates
OH
OH
12
c
d
d
CH3
CH3
65
CH3
TsO
1l
O
O
2a
1a
OH
OH
OH
13
d
d
OHC
2
3
4
68
64
62
1m
NO2
TsO
NO2
2b
1b
OH
OH
OH
14
15
H3C
d
1n
O
CHO
TsO
CHO
2c
1c
OH
OH
Ph
OH
OH
82
O2N
I
O2N
OCH3
OCH3
OH
OTs
2o
1o
1d
2d
O
O
OH
OH
16
17
c
d
d
H3C
1p
5
6
61
58
NH2
NH2
TsO
OH
1e
2e
O
O
c
OH
OH
1q
OPh
OH
OPh
TsO
OCH3
CH3
OCH3
2f
1f
O
O
18
92
OTs
OTs
O
O
OH
5
4
a
7
8
CH3
78
72
Satisfactory spectral data were obtained on all the products.
Isolated yields after purification by column chromatography.
Reaction was sluggish.
H3C
CH3
b
c
H3C
1g
O
2g
d
O
No reaction.
CHO
CHO
OH
X
OH
OH
OH
PhI(OH)OTs, CH2Cl2
stirring at room temp.
TsO
X
TsO
2h
1h
2
1
OH
CH3
OH
X = NO2 (b); CHO (c); COOCH3 (d); CONH2 (e); COOPh (f)
9
c
d
d
Scheme 2. Reaction of 2-substituted phenol derivatives (1bef) with HTIB leading to
formation of 4-tosyloxy-2-substituted phenol derivatives (2bef).
1i
2.3. Phenols containing electron-withdrawing and electron-
releasing substituents at the para position
10
c
OCH3
OH
1j
The phenols, which contain electron-withdrawing substituents at
the para position (Table 1, entries 13e15) also did not follow the same
trend. When the reaction of p-nitrophenol was carried out under
similar reaction conditions, the 2-hydroxy-5-nitrodiphenyliodonium
tosylate (2o) was obtained in 82% rather than any tosyloxylated
product (Table 1,entry15).Thetosylate2o on basificationwith aqueous
potassium carbonate resulted in the formation of ylide 3 (Scheme 3).
11
d
d
CHO
1k

5830
O. Prakash et al. / Tetrahedron 66 (2010) 5827e5832
OH
PhI(OH)OTs,
CH2Cl2
O
OH
aq. K2CO3
rt
O2N
I Ph
OTs
O2N
I Ph
O2N
1o
2o
3
Scheme 3. Reaction of p-nitrophenol (1o) with HTIB.
Similar iodonium ylides/salts have previously been reported by
Kokil and Nair by the reaction of p-nitrophenol with IBD in acetic
acid.14b To our surprise p-hydroxyacetophenone and p-hydroxy-
bezaldehyde under similar conditions did not give neither tosy-
loxylated product nor iodonium salt/ylide (Table 1, entries 13 and
14). In the case of p-cresol, the reaction was also sluggish (Table 1,
entry 16).
aromatic rings. Koser et al. have also suggested SET mechanism for
oxidative-substitution reaction of polycyclic aromatic hydrocar-
bons with HTIB in dichloromethane.15i Thus, we considered the
possibility of SET mechanism for tosyloxylation of phenols under
study. In order to determine whether the reaction involves phenolic
group, we carried out the reaction of o-methoxyacetophenone (4)
in place of o-hydroxyacetophenone with HTIB in dichloromethane
under similar reaction conditions. However, the reaction afforded
a-tosyloxyketone 5 rather than p-tosyloxylated product 6 in 92%
2.4. Phenols containing electron-withdrawing and electron-
yield (Scheme 5). This experiment suggested that the ring tosyl-
oxylation could not proceed without phenolic group and therefore
probably proceeds via ligand exchange between phenolic group
and HTIB as shown in Scheme 4. It is also relevant to mention that
involvement of the intermediate of the Type B (similar to Type A)
has been suggested in on thallium(III) mediated oxidation of some
o-hydroxyacetophenones (based upon 1H NMR measurements).23
releasing substituents at the meta position
Unfortunately, the method for tosyloxylation of phenols was not
applicable to the m-substitued phenols. While in the case of m-
hydroxybezaldehye (Table 1, entry 11) only starting m-hydroxy-
bezaldehyde was recovered, the reaction of m-cresol (Table 1, entry
12) resulted in a complex mixture without affording any desired
tosyloxylated product.
OCH3
2.5. Mechanistic considerations
OTs
It is evident from the results of the present study, summarized in
Table
1 that it is necessary to have electron-withdrawing
O
OCH3
CH3
5
PhI(OH)OTs, CH2Cl2
rt
substituents at the ortho position of the phenolic group for the
successful tosyloxylation of aromatic ring. Although, actual role of
various electron-withdrawing substituents is not clear and detailed
understanding of the reaction mechanism awaits further study, the
plausible mechanism suggested for the tosyloxylation of phenols is
analogous to the reported studies on hypervalent iodine oxidation
of phenols21 and is outlined in Scheme 4. The mechanism probably
involves Type A intermediate, in which the phenolic oxygen
initially reacts with iodine of HTIB. This is followed by the
nucleophilic attack of ꢀOTs at the para (or ortho when para position
is not vacant) position of phenol ring to give the tosyoxylated
product 2, together with iodobenzene.
OCH3
CH3
O
4
TsO
O
6
Scheme 5. Reaction of o-methoxyacetophenone (4) with HTIB.
O
Tl(NO3)2
OH
Ph
..
Ph
I
OTs
- OTs
O
OH
O
X
I
OH
X
Me
TsO
1
A
B
3. Conclusion
O
OH
The tosyloxylation of phenols reported in this study demonstrates
an interesting application of HTIB in aromatic substitution of certain
phenolic compounds containing electron-withdrawing substitution
at their ortho position. The noteworthy features of this study are:
PhI,
H2O
H
X
TsO
X
OTs
2
(i) Oxidation of monohydric phenols 1 containing electron-
withdrawing substituents at ortho position with 1 equiv of
HTIB offers a novel and efficient route for their tosyloxylation
at para position. The tosyloxy derivatives 2aeh obtained from
this study are hitherto unknown and seem to be useful pre-
cursors for further transformations such as carbonecarbon
coupling reaction such as arylation of enolates derived from
carbonyl compounds.24
Scheme 4. Plausible mechanism for the formation of 4-tosyloxy-2-substituted
phenols (2).
It may be mentioned that Kita et al. in 1994,22 determined the
SET oxidation ability of IBTA toward phenyl ethers, affording the
corresponding aromatic cation radicals. Since then, they have
utilized IBTA as selective and efficient oxidizing agent that enables
a variety of direct CeH functionalization of aromatic and hetero

O. Prakash et al. / Tetrahedron 66 (2010) 5827e5832
5831
1004 cmꢀ1
;
1H NMR (300 MHz, CDCl3)
d
2.39 (s, 3H, CH3), 3.86 (s,
(ii) Inenolizableketones, COCH3 group,whichispronetoundergo
a-
tosyloxylation remains intact under the reaction conditions.25
3H, -OCH3), 6.78 (d, 1H, J¼9.0 Hz), 6.87 (dd, 1H, J¼9.0, 2.9 Hz), 7.26
(d, 2H, J¼8.4 Hz), 7.50 (d, 1H, J¼2.9 Hz), 7.63 (d, 2H, J¼8.4 Hz), 10.66
(s, 1H, OH); elemental analysis calcd (%) for C15H14O6S: C, 55.90; H,
4.35; found: C, 55.84; H 4.21.
(iii) In the case of o-hydroxybenzamide (2e), CONH2 group does
not undergo Hoffmann reaction to produce the amine with
HTIB, as reported earlier.26
(iv) The reaction conditions are mild and further oxidative-sub-
stitution of phenolic group is not observed.
4.2.5. 2-Carbamoyl-4-tosyloxyphenol 2e. Brownish crystals; mp
145e146 ꢁC; IR (KBr): 3466, 3340, 3219, 1654, 1450, 1372, 1258,
1179, 1095, 1029 cmꢀ1 1H NMR (300 MHz, CDCl3)
; d 2.46 (s, 3H,
4. Experimental section
4.1. General information
CH3), 6.11 (br s, 2H, eNH2), 6.79 (d, 1H, J¼9.0 Hz), 6.89 (dd, 1H,
J¼9.0, 2.0 Hz), 7.21 (d, 1H, J¼2.0 Hz), 7.33 (d, 2H, J¼8.1 Hz), 7.68 (d,
2H, J¼8.1 Hz), 12.17 (s, 1H, OH); elemental analysis calcd (%) for
C14H13NO5S: C, 54.72; H, 4.23; found: C, 54.61; H 4.13.
Melting points (mp) were taken in open capillaries and are
uncorrected. The IR spectra were recorded on PerkineElmer IR1800
spectrophotometer. The 1H NMR spectra were recorded in CDCl3 on
Bruker 300 MHz instrument with TMS as an internal standard. The
4.2.6. 2-Carbaphenoxy-4-tosyloxyphenol 2f. Brownish crystals; mp
105e106 ꢁC; IR (KBr): 3442, 1691, 1487, 1377, 1256, 1178, 1083,
1004 cmꢀ1 1H NMR (300 MHz, CDCl3)
; d 2.43 (s, 3H, CH3), 6.79 (d,
data are reported as follows: chemical shift in parts per million (d)
1H, J¼9.0 Hz), 6.88 (dd, 1H, J¼9.0, 2.9 Hz), 7.23 (d, 2H, J¼8.1 Hz),
7.33 (m, 3H), 7.39 (m, 2H), 7.56 (d, 1H, J¼2.9 Hz), 7.63 (d, 2H,
J¼8.1 Hz), 10.71 (s, 1H, OH); elemental analysis calcd (%) for
C20H16O6S: C, 62.50; H, 4.17; found: C, 62.55; H, 4.06.
and coupling constant (Hz). Elemental analyses were carried out in
PerkineElmer 2400 instrument. PhI(OH)OTs (HTIB, Koser’s re-
agent) was prepared according to the literature method.27 Solvents
and all starting materials were obtained from commercial suppliers
and were used without further purification.
4.2.7. 2-Acetyl-4-methyl-6-tosyloxyphenol 2g. Colorless crystals;
mp 121e122 ꢁC; IR (KBr): 3451, 1648, 1469, 1374, 1260, 1172, 1085,
4.2. Typical procedure for synthesis of 4-tosyloxy-2-
substituted phenols (2)
1003 cmꢀ1 1H NMR (300 MHz, CDCl3)
; d 2.31 (s, 3H, CH3), 2.45 (s,
3H, CH3), 2.62 (s, 3H, CH3), 7.31, (d, 2H, J¼8.1 Hz), 7.40 (d, 1H,
J¼1.8 Hz), 7.44 (d, 1H, J¼1.8 Hz), 7.84, (d, 2H, J¼8.1 Hz), 12.02 (s, 1H,
OH); elemental analysis calcd (%) for C16H16O5S: C, 60.00; H, 5.00;
found: C, 59.89; H, 5.08.
To a stirred solution of o-hydroxyacetophenone (1a, 136 mg,
1.0 mmol) in dichloromethane (50 ml) was added HTIB (431 mg,
1.1 mmol) in one portion. The resulting mixture was allowed to stir
at room temperature. HTIB was highly insoluble in dichloro-
methane, gradually disappeared as the reaction proceeded. The
stirring was allowed to continue for about 3 h. After completion of
the reaction (as monitored by TLC), the crude product 2a was
purified by column chromatography on silica gel using 1:10
EtOAcePetroleum ether as eluent; mp 102e103 ꢁC, yield, 280 mg
(65%), entry 1, Table 1.
4.2.8. 1-Formyl-6-tosyloxy-2-naphthol 2h. Colorless crystals; mp
152e153 ꢁC; IR (KBr): 3410, 2834, 1672, 1444, 1293, 1247, 1170,
1021 cmꢀ1; 1H NMR (300 MHz, CDCl3)
d 2.39 (s, 3H, CH3), 7.11 (d, 1H,
J¼6.9 Hz), 7.15 (dd, 1H, J¼6.9, 21.8 Hz), 7.25 (d, 2H, J¼6.3 Hz), 7.41 (d,
1H, J¼1.8 Hz), 7.66 (d, 2H, J¼6.3 Hz), 7.81 (d,1H, J¼6.9 Hz), 8.19 (d,1H,
J¼6.9 Hz), 10.67 (s, 1H, eCHO), 13.05 (s, 1H, OH); elemental analysis
calcd (%) for C18H14O5S: C, 63.16; H, 4.09; found: C, 62.99; H, 4.01.
4.2.1. 2-Acetyl-4-tosyloxyphenol 2a. Colorless crystals; mp 102e
4.3. Synthesis of 2-hydroxy-5-nitrodiphenyliodonium ylide 3
103 ꢁC; IR (KBr): 3450, 1651, 1483, 1377, 1285, 1167, 1089,
1024 cmꢀ1
;
1H NMR (300 MHz, CDCl3)
d
2.47 (s, 3H, CH3 of ꢀOTs),
4.3.1. 2-Hydroxy-5-nitrodiphenyliodonium tosylate 2o. To a stirred
solutionof p-nitrophenol (1o, 347 mg, 2.5 mmol) in dichloromethane
(50 ml) was added HTIB (1077 mg, 2.8 mmol) in one portion. The
resulting mixture was allowed to stir at room temperature. HTIB,
initially insoluble in dichloromethane, gradually disappeared as the
reaction proceeded. After stirring the reaction mixture for 2 h the
yellow colored solid was separated out and filtered; yield 632 mg
(82%); mp 191e192 ꢁC; IR (KBr): 3448, 1540, 1490, 1381, 1352, 1250,
2.52 (s, 3H, CH3), 6.87 (d, 1H, J¼9.0 Hz), 7.01 (dd, 1H, J¼9.0, 2.7 Hz),
7.35 (d, 2H, J¼8.1 Hz), 7.37, (d, 1H, J¼2.7 Hz), 7.71 (d, 2H, J¼8.1 Hz),
12.15 (s, 1H, OH); elemental analysis calcd (%) for C15H14O5S: C,
58.82; H, 4.58; found: C, 58.91; H 4.43.
Other derivatives were prepared in a similar manner. The
characterization data of the compounds prepared in this study is
given as under.
1180,1089,1005 cmꢀ1; 1H NMR (300 MHz, CD3OD)
d 2.37 (s, 3H, CH3),
4.2.2. 2-Nitro-4-tosyloxyphenol 2b. Yellow crystals; mp 112e113 ꢁC;
7.21e7.24 (m, 3H), 7.53 (d, 2H, J¼7.8 Hz), 7.67e7.70 (m, 3H), 8.19 (d,
IR (KBr): 3432,1528,1490,1381,1358,1259,1177,1089,1005 cmꢀ1; 1H
2H, J¼7.8 Hz), 8.39 (dd, 1H, J¼8.7, 2.7 Hz), 9.10 (d, 1H, J¼2.7 Hz).
NMR (300 MHz, CDCl3)
d
2.48 (s, 3H, CH3), 7.11 (d, 1H, J¼9.0 Hz), 7.29
(dd, 1H, J¼9.0, 3.0 Hz), 7.36 (d, 2H, J¼8.1 Hz), 7.68 (d, 1H, J¼3.0 Hz),
7.73 (d, 2H, J¼8.1 Hz), 10.49 (s, 1H, OH); elemental analysis calcd (%)
for C13H11NO6S: C, 50.49; H, 3.56; found: C, 50.38; H, 3.58.
4.3.2. 2-Hydroxy-5-nitrodiphenyliodonium ylide 3. The suspension
of tosylate 2o (513 mg, 1.0 mmol) with aqueous potassium carbon-
ate (10 ml, 10%) was stirred at room temperature for 30 min. The
resulting yellow colored solid was filtered and washed with water;
yield 325 mg (95%); mp 131e132 ꢁC (lit.13b mp 133 ꢁC); IR (KBr):
3460,1550,1461,1381,1259,1010 cmꢀ1; 1H NMR (300 MHz, CD3OD)
4.2.3. 2-Formyl-4-tosyloxyphenol 2c. Brownish crystals; mp 219e
220 ꢁC; IR (KBr): 3455, 2866, 1666, 1473, 1374, 1265, 1172, 1083,
1003 cmꢀ1
;
1H NMR (300 MHz, CDCl3)
d
2.47 (s, 3H, CH3), 6.88 (d,
d
6.35 (d,1H, J¼9.3 Hz), 7.49e7.54 (m, 2H), 7.64e7.68 (m,1H), 7.94 (d,
1H, J¼9.0 Hz), 7.01 (dd,1H, J¼9.0, 2.8 Hz), 7.28 (d,1H, J¼2.8 Hz), 7.34
(d, 2H, J¼8.4 Hz), 7.71 (d, 2H, J¼8.4 Hz), 9.78 (s, 1H, eCHO), 10.96 (s,
1H, OH); elemental analysis calcd (%) for C14H12O5S: C, 57.53; H,
4.11; found: C, 57.61; H, 4.03.
1H, J¼9.1 Hz), 8.10 (d, 2H, J¼7.5 Hz), 8.38 (d, 1H, J¼2.7 Hz).
4.4. Synthesis of o-methoxy- -tosyloxyacetophenone 5
a
To a stirred solution of o-methoxyacetophenone (4, 150 mg,
1.0 mmol) in dichloromethane (40 ml) was added HTIB (431 mg,
1.1 mmol) in one portion. The resulting mixture was allowed to stir
4.2.4. 2-Carbamethoxy-4-tosyloxyphenol 2d. Brownish crystals; mp
91e92 ꢁC; IR (KBr): 3445, 1682, 1490, 1384, 1259, 1175, 1083,

5832
O. Prakash et al. / Tetrahedron 66 (2010) 5827e5832
Synth. Commun. 1990, 20, 2907; (d) Callinan, A.; Chen, Y.; Morrow, G. W.;
Swenton, J. S. Tetrahedron Lett. 1990, 31, 4551; (e) Fleck, A. E.; Hobart, J. A.;
Morrow, W. Synth. Commun. 1992, 22, 179; (f) Mallik, U. K.; Mallik, U. K. Indian J.
Chem. 1992, 30B, 611; (g) Pelter, A.; Elegendy, S. A. J. Chem. Soc., Perkin Trans. 1
1993, 1891; (h) Mckillop, A.; McLaren, L.; Taylor, R. K. J. Chem. Soc., Perkin Trans.
1 1994, 2047; (i) Saby, C.; Luong, J. H. T. Chem. Commun. 1997, 1197; (j) Mal, D.;
Roy, H. N.; Hazra, N. K.; Adhikari, S. Tetrahedron 1997, 53, 2177.
at room temperature for about 3 h. The solvent was evaporated in
vacuo. The gummy mass so obtained was triturated with pet ether
(60e80 ꢁC) to remove iodobenzene. The resulting colorless solid
was thoroughly washed with water to remove p-toluenesulphonic
acid formed as a byproduct. The solid was recrystallized with ace-
tonitrile to give the pure o-methoxy-a-tosyloxyacetophenone as
11. (a) Tamura, Y.; Yakura, T.; Haruta, J.; Kita, Y. J. Org. Chem. 1987, 52, 3927; (b)
Mckillop, A.; McLaren, L.; Taylor, R. J. K.; Watson, R. J.; Lewis, N. Synlett 1992, 201;
(c) Wipf, P.; Kim, Y. Tetrahedron Lett. 1992, 33, 5477; (d) Kacan, M.; Koyuncu, D.;
Mckillop, A. J. Chem. Soc., PerkinTrans.11993,1771; (e) Wipf, P.; Kim, Y. J. Org. Chem.
1993, 58, 1649; (f) Wipf, P.; Kim, Y.; Fritch, P. C. J. Org. Chem. 1993, 58, 7195.
12. (a) Kaiser, A.; Koch, W.; Scheer, M.; Wolcke, U. Helv. Chim. Acta 1970, 53, 1708;
(b) Moriarty, R. M.; Prakash, O.; Prakash, I.; Musallam, H. A. J. Chem. Soc., Chem.
Commun. 1984, 1342; (c) Moriarty, R. M.; Prakash, O.; Prakash, I.; Duncan, M. P.
Synth. Commun. 1986, 16, 1239; (d) Prakash, O.; Goyal, S.; Pahuja, S.; Singh, S. P.
Synth. Commun. 1990, 20, 1409; (e) Khanna, M. S.; Sangeeta; Garg, C. P.; Kapoor,
R. P. Synth. Commun. 1992, 22, 2555.
colorless crystalline solid (5, yield 294 mg, 92%); mp 91e92 ꢁC; IR
(KBr): 1660, 1571, 1461, 1381, 1348, 1271, 1167, 1078, 1003 cmꢀ1; 1H
NMR (300 MHz, CDCl3)
d 2.46 (s, 3H, CH3), 3.94 (s, 3H, OCH3), 5.27
(s, 2H, CH2), 6.97e7.06 (m, 2H), 7.36 (d, 2H, J¼8.1 Hz), 7.55 (td, 1H,
J¼8.4, 1.8 Hz), 7.86 (dd, 1H, J¼8.4, 1.8 Hz), 7.91 (d, 2H, J¼8.1 Hz);
elemental analysis calcd (%) for C16H16O5S: C, 60.00; H, 5.00; found:
C, 59.83; H, 5.09.
13. (a) Szantay, C.; Blasko, G.; Barczai-Beke, M.; Pechy, P.; Dornyei, G. Tetrahedron
Lett. 1980, 21, 3509; (b) White, J. D.; Chong, W. K.; Thirring, K. J. Org. Chem. 1983,
48, 2300; (c) White, J. D.; Caravati, G.; Kline, T. B.; Edstrom, E.; Rice, K. C.; Bross,
A. Tetrahedron 1983, 39, 2393; (d) Vanderlaan, D. G.; Schwartz, M. A. J. Org.
Chem. 1985, 50, 743; (e) Burnett, D. A.; Hart, D. J. J. Org. Chem. 1987, 52, 5662; (f)
Schwartz, M. A.; Pham, P. T. K. J. Org. Chem. 1988, 53, 2318.
14. (a) Fox, A. R.; Pausacker, K. H. J. Chem. Soc. 1957, 295; (b) Kokil, P. B.; Nair, P. M.
Tetrahedron Lett. 1977, 45, 4113; (c) Spyroudis, S.; Varvoglis, A. J. Chem. Soc.,
Perkin Trans. 1 1984, 135.
Acknowledgements
We are thankful to UGC, New Delhi for the award of Junior Re-
search Fellowship to M.K. and Council for Scientific and Industrial
Research (CSIR), New Delhi (Grant No CSIR 01(2186)/07/EMR-II) for
financial support of this work.
15. (a) Rebrovic, L.; Koser, G. F. J. Org. Chem. 1984, 49, 2462; (b) Moriarty, R. M.;
Vaid, R. K.; Koser, G. F. Synlett 1990, 365; (c) Prakash, O.; Saini, N.; Sharma, P. K.
Heterocycles 1994, 38, 40; (d) Koser, G. F. Aldrichimica Acta 2001, 34, 89; (e) Lee,
J. C.; Lee, J. Y.; Lee, S. J. Tetrahedron Lett. 2004, 45, 4939; (f) Justik, M. W.; Koser,
G. F. Tetrahedron Lett. 2004, 45, 6159; (g) Prakash, O.; Batra, A.; Chaudhri, V.;
Prakash, R. Tetrahedron Lett. 2005, 46, 2877; (h) Justik, M. W.; Koser, G. F.
Molecules 2005, 10, 217; (i) Koser, G. F.; Telu, S.; Laali, K. K. Tetrahedron Lett.
2006, 47, 7011; (j) Kumar, R. Synlett 2007, 2764; (k) Prakash, O.; Kumar, R.;
Sharma, D.; Pannu, K.; Kamal, R. Synlett 2007, 2189; (l) Karade, N. N.; Gampa-
war, S. V.; Kondre, J. M.; Shinde, S. V. Tetrahedron Lett. 2008, 49, 4402; (m)
Karade, N. N.; Tiwari, G. B.; Gampawar, S. V.; Shinde, S. V. Heteroat. Chem. 2009,
20, 172; (n) Dohi, T.; Ito, M.; Yamaoka, N.; Morimoto, K.; Fujioka, H.; Kita, Y.
Tetrahedron 2009, 65, 10797.
References and notes
1. (a) Mihailovic, M. L.; Cekovic, Z., Part I In The Chemistry of the Hydroxyl Group;
Patai, S., Ed.; Wiley: London, 1971; (b) Higuchi, T. In Biosynthesis and Bio-
degradation of Wood Components; Higuchi, T., Ed.; Academic: London, 1985,
Chapter 6; (c) Ayers, D. C.; Loike, J. D. Lignans: Chemical, Biological, and Clinical
properties; Cambridge University Press: Cambridge, 1990, Chapter 7.
2. Deya, P. M.; Dopico, M.; Raso, A. G.; Morey, J.; Saa, J. M. Tetrahedron 1987, 43, 3523.
3. Taup, D.; Kuo, C. H.; Slates, H. L.; Wendler, N. L. Tetrahedron 1963, 19, 1.
4. Dewar, M. J. S.; Nakaya, T. J. Am. Chem. Soc. 1968, 90, 7134.
5. (a) Schwartz, A.; Mami, I. S. J. Am. Chem. Soc. 1975, 97, 1239; (b) Mckillop, A.;
Perry, D. H.; Edwards, M.; Antus, S.; Farkas, L.; Nogradi, M.; Taylor, E. C. J. Org.
Chem. 1976, 41, 282.
16. Prakash, O.; Pundeer, R.; Kaur, H. Synthesis 2003, 2768.
17. (a) Prakash, O.; Tanwar, M. P.; Goyal, S.; Pahuja, S. Tetrahedron Lett. 1992, 33,
6519; (b) Spyroudis, S.; Tarantili, P. Tetrahedron 1994, 50, 11541; (c) Prakash, O.;
Sharma, V.; Tanwar, M. P. Can. J. Chem. 1999, 77, 1243.
18. Prakash, O.; Kaur, H.; Sharma, V.; Bhardwaj, V.; Pundeer, R. Tetrahedron Lett.
2004, 45, 9065.
19. Van De Water, R. W.; Hoarau, C.; Pettus, T. R. R. Tetrahedron Lett. 2003, 44, 5109
The only example of tosyloxylation of phenols with HTIB reported till date is
tosloxylation of 3-[1-(pyrrolidin-1-yl)-2-oxy-ethanon-2-yl]-4-ethylphenol.
20. In case of salicylic acid only starting material was recovered.
6. Brussee, J.; Jansen, A. C. A. Tetrahedron Lett. 1983, 24, 3261.
7. (a) Barton, D. H. R.; Deflorin, A. M.; Edwards, O. E. J. Chem. Soc. 1956, 530; (b)
Thyagarajan, B. S. Chem. Rev. 1958, 58, 439; (c) Battersby, A. R.; Brown, T. H.;
Clements, J. H. J. Chem. Soc. 1965, 4550; (d) Hewgill, F. R.; Middleton, B. S. J.
Chem. Soc. 1967, 2316; (e) Pelter, A.; Bradshaw, J.; Warren, R. F. Phytochemistry
1971, 10, 835; (f) Balogh, V.; Fetizon, M.; Golfier, M. J. Org. Chem. 1971, 36, 1339;
(g) Tobinaga, S.; Kotani, E. J. Am. Chem. Soc. 1972, 94, 309.
8. (a) Varvoglis, A. Synthesis 1984, 709; (b) Moriarty, R. M.; Prakash, O. Org. React.
2001, 57, 327.
21. (a) Moriarty, R. M.; Prakash, O. Acc. Chem. Res. 1986, 19, 244; (b) Ligand Coupling
Reactions with Heteroatomic Compounds; Finet, P., Ed.Tetrahedron Organic
Chemistry Series; Pergamon Press: Oxford: 1998; Vol.18; (c) Ozanne-Beeaudenon,
A.; Quideau, S. Angew. Chem., Int. Ed. 2005, 44, 7065 and references cited therein.
22. Kita, Y.; Okuno, T.; Egi, M.; Jeo, k.; Takeda, Y.; Akai, S. Synlett 1994, 1039.
23. Horie, T.; Yamada, T.; Kawamura, Y.; Tsukayama, M.; Kuramoto, M. J. Org. Chem.
1992, 57, 1038.
24. Nguyen, H. N.; Huang, X.; Buchwald, S. L. J. Am. Chem. Soc. 2003, 125, 11818.
25. Koser, G. F.; Relenyi, A. G.; Kalos, A. N.; Rebrovic, L.; Wettach, R. H. J. Org. Chem.
1982, 47, 2487.
9. For recent reviews and publications, see: (a) Varvoglis, A. Tetrahedron 1997, 53,
1179; (b) Varvoglis, A. Hypervalent Iodine in Organic Synthesis; Academic: San
Diego, 1997; (c) Kitamura, T.; Fujiwara, Y. Org. Prep. Proced. Int. 1997, 29, 409; (d)
Kirshning, A. Eur. J. Org. Chem. 1998, 11, 2267; (e) Ochiai, M. In Chemistry of
Hypervalent Compounds; Akiba, K., Ed.; Wiley-VCH: New York, NY, 1999,
Chapter 12; (f) Zhdankin, V. V.; Stang, P. J. Chem. Rev. 2002, 102, 2523; (g) Wirth,
T.; Ochiai, M.; Zhdankin, V. V.; Koser, G. F.; Tohma, H.; Kita, Y. Hypervalent Iodine
Chemistry-Modern Developments in Organic Synthesis. Top. Curr. Chem.;
Springer: Berlin, 2003; (h) Tohma, H.; Kita, Y. Adv. Synth. Catal. 2004, 346, 111;
(i) Moriarty, R. M. J. Org. Chem. 2005, 70, 2893; (j) Wirth, T. Angew. Chem., Int. Ed.
2005, 44, 3656; (k) Zhdankin, V. V.; Stang, P. J. Chem. Rev. 2008, 108, 5299; (l)
Ochiai, M. Synlett 2009, 159; (m) Dohi, T.; Kita, Y. Chem. Commun. 2009, 2073.
10. (a) Lewis, N.; Wallbank, P. Synthesis 1987, 1103; (b) Tamura, Y.; Yakura, T.;
Tohma, H.; Kikuuchi, K.; Kita, Y. Synthesis 1989, 126; (c) Barret, R.; Daudon, M.
26. (a) Lazbin, I. M.; Koser, G. F. J. Org. Chem. 1986, 51, 2669; (b) Vasudevan, A.;
Koser, G. F. J. Org. Chem. 1988, 53, 5158.
27. (a) Neiland, O.; Karele, B. Zh. Org. Khim. 1970, 6, 885; J. Org. Chem. USSR (Eng.
Transl.) 1970, 6, 889; (b) Koser, G. F.; Wettach, R. H. J. Org. Chem. 1977, 42, 1476.