A new application of hypervalent iodine (λ5) reagents with organosulfonic acids for direct α-organosulfonyloxylation carbonyl compounds

Article abstract of DOI:10.1055/s-2008-1072508

Hypervalent iodine (λ⁵) reagents in combination with p-toluenesulfonic acid when reacted with ketones under reflux temperature in acetonitrile gave α-tosyloxy ketones in moderate to excellent yields. The reaction was developed further for both

Full text of DOI:10.1055/s-2008-1072508

LETTER
987
A New Application of Hypervalent Iodine (l5) Reagents with Organosulfonic
Acids for Direct a-Organosulfonyloxylation Carbonyl Compounds
New
Application
o
l
f
H
ypehrvalent Iodin 5
a
e
(
l
)
Reag
s
ents S. Mahajan, Krishnacharya G. Akamanchi*
Department of Pharmaceutical Sciences & Technology, Institute of Chemical Technology, Matunga, Mumbai 400 019, India
Fax +91(22)24145614; E-mail: kgap@rediffmail.com
Received 22 November 2007
In continuation of our studies towards the development of
Abstract: Hypervalent iodine (l5) reagents in combination with p-
novel applications of hypervalent iodine (l5) regents, we
toluenesulfonic acid when reacted with ketones under reflux tem-
perature in acetonitrile gave a-tosyloxy ketones in moderate to ex-
cellent yields. The reaction was developed further for both ketones
wish to report direct a-organosulfonyloxylation of various
ketones and dicarbonyl compounds using these reagents
and dicarbonyl compounds using Dess–Martin periodinane reagent in combination with organosulfonic acids. The added ad-
in combination with p-toluenesulfonic acid and methanesulfonic ac-
id, to give mono-a-tosyloxy and mono-a-mesyloxy products in very
high to excellent yields.
vantage of this method is that there is no need for prior
preparation of sulfonyloxy reagents as in the case of
HTIB.5 For preliminary experiments, 4-methoxyace-
Key words: hypervalent iodine reagents, Dess–Martin periodinane,
carbonyl compounds, organosulfonic acids, a-organosulfonyl-
oxylation
tophenone was chosen as a model substrate and reactions
were carried out using 1.5 equivalents of DMP in combi-
nation with 2.0 equivalents of p-toluenesulfonic acid at
room temperature in acetonitrile. The expected reaction
did not occur and unreacted starting material was recov-
Hypervalent iodine reagents are known for direct oxida-
ered. When the reaction was performed at reflux temper-
tive a-carbon–heteroatom bond formation in carbonyl
compounds.1 The reagents being nonmetallic, highly se-
lective, and mild oxidants have attracted considerable at-
tention towards exploration and development of new
methodologies.2 The a-tosyloxy and a-mesyloxy carbon-
yl compounds are versatile precursors for construction of
biologically important heterocyclic ring systems such as
thiazoles, imidazoles, oxazoles pyrazines, pyrazoles, lac-
tones, benzofurans, benzopyrazines, benzoxazines, ben-
zothiazines, imidazo[2,1-b]thiazoles and thiazolo[3,2-
a]benzimidazoles.3
ature, it proceeded smoothly and the corresponding a-
tosyloxy ketone was obtained in 94% yield with complete
consumption of starting material (Table 1, entry 2).
Table 1 a-Tosyloxylation Using Hypervalent Iodine (l5) Reagentsa
O
O
O-4-Ts
reagent system
conditions
Me
MeO
MeO
Entry
Reagent
Reagent/PTSA Conditions
molar ratio
Yield
(%)b
Our group has been working extensively on the develop-
ment of novel methodologies using hypervalent iodine
(l5) reagents, mainly, o-iodoxybenzoic acid (IBX) and
Dess–Martin periodinane (DMP).4 Throughout the litera-
ture there is no report on a-organosulfonyloxylation of
carbonyl compounds using these reagents. However triva-
lent iodine (l3) reagents are known to promote direct a-or-
ganosulfonyloxylation of carbonyl compounds. Among
them are (hydroxy tosyloxy iodo) benzene (HTIB),5 (di-
acetoxyiodo)benzene organosulfonic acid under solvent-
free conditions,6a (diacetoxyiodo)benzene and p-toluene-
sulfonic acid under microwave irradiation,6b iodosylben-
1
2
3
4
5
DMP
DMP
IBX
1.5/2
1.5/2
2/2
r.t., 10 h
NR
94
Reflux, 2.5 h
Reflux, 3 h
Reflux, 10 h
Reflux, 10 h
78
HIO3
HIO4
2.5/2.5
2.5/2.5
65c
55c
a Reactions were carried out on 5 mmol scale.
b Isolated yields using column chromatography.
c Unreacted starting material was recovered, NR = no reaction.
zene/p-toluenesulfonic
acid
monohydrate,6c
m-
chloroperbenzoic acid/p-toluenesulfonic acid in presence
of PhI,6d poly(4-hydroxy tosyloxy iodo)styrenes,6e and re-
cently enantioselective a-tosyloxylation using enantioen-
riched iodoarenes/m-chloroperbenzoic acid.6f Other
methods for direct a-p-tosyloxylation include thallium p-
tolylsulfonate6g and N-methyl-O-tosylhydroxylamine.6h
Encouraged by these results, other hypervalent iodine
compounds IBX, HIO3, and HIO4 were also examined and
all were found to be viable. However, the reactions were
slow and in some cases unreacted starting material re-
mained even after 10 hours and yields were moderate
(Table 1, entries 4 and 5).
For further investigations DMP was chosen and selectivi-
ty, general applicability, and extension for other organo-
sulfonic acids such as methanesulfonic acid were studied.
Various ketones and dicarbonyl compounds were reacted
SYNLETT 2008, No. 7, pp 0987–0990
Advanced online publication: 17.03.2008
DOI: 10.1055/s-2008-1072508; Art ID: D37607ST
© Georg Thieme Verlag Stuttgart · New York
x
x.
x
x.
2
0
0
8

988
U. S. Mahajan, K. G. Akamanchi
LETTER
with DMP in combination with p-toluenesulfonic acid and obtained in very good to excellent isolated yields. The re-
methanesulfonic acid, respectively.7,8 In all cases the cor- sults are summarized in Table 2.
responding a-organosulfonyloxylated compounds were
Table 2 DMP-Mediated a-Organosulfonyloxylation of Various Carbonyl Compoundsa
Entry
Substrate
Productb
Yieldc (%, reaction time, h)
R = OMs
R = O-4-Ts
O
O
86
(2.5)
90
(2.5)
R
1
2
3
Me
O
O
O
82
(3.0)
88
(3.0)
R
R
Me
Me
Cl
Cl
Cl
Cl
O
Cl
78
(3.5)
90
(3.5)
Cl
O
O
80
(3.5)
86
(3.5)
R
4
Me
O2N
O2N
O
O
82
(3.5)
92
(3.5)
R
5
6
Me
Me
Me
O
O
79
(2.5)
94
(2.5)
R
Me
MeO
MeO
O
O
75
(4.5)
84
(4.5)
R
7
Me
O
Cl
4-ClC6H4O
O
Cl
4-ClC6H4
O
78
(3.0)
82
(3.0)
8
9
R
O
O
72
(3.0)
84
(3.0)
R
Me
O
O
R
O
O
65
(4.5)
72
(4.5)
10
O
O
80
(2.5)
87
(2.5)
11
12
R
Me
Me
Me
O
76
(3.0)
80
(3.0)
O
R
Synlett 2008, No. 7, 987–990 © Thieme Stuttgart · New York

LETTER
New Application of Hypervalent Iodine (l5) Reagents
989
Table 2 DMP-Mediated a-Organosulfonyloxylation of Various Carbonyl Compoundsa (continued)
Entry
Substrate
Productb
Yieldc (%, reaction time, h)
R = OMs
R = O-4-Ts
O
O
O
O
68
(2.5)
72
(2.5)
13
14
15
Me
Me
R
O
O
O
O
73
(2.5)
78
(2.5)
Me
Me
O
Me
Me
O
R
O
O
72
(3.0)
80
(3.0)
OEt
OEt
R
a Reactions were conducted on 5 mmol scale in MeCN at reflux temperature with DMP (1.5 equiv) and organosulfonic acid (2.0 equiv).
b Compounds were characterized by IR, 1H NMR and physical constants.8
c Isolated yield after column chromatography.
Org. Synth. 2005, 2, 121. (d) Wirth, T. Angew. Chem. Int.
Ed. 2005, 44, 3656. (e) Nicolaou, K. C.; Montagnon, T.;
Baran, P. S. Angew. Chem. Int. Ed. 2002, 41, 993.
(f) Nicolaou, K. C.; Gray, D. L.; Montagnon, F. T.; Harrison,
S. T. Angew. Chem. Int. Ed. 2002, 41, 996. (g) Nicolaou, K.
C.; Montagnon, T.; Baran, P. S. Angew. Chem. Int. Ed. 2002,
41, 1386. (h) Katritzky, A. R.; Duell, B. L.; Durst, H. D.;
Knier, B. L. J. Org. Chem. 1988, 53, 3972. (i) Zhdankin, V.
V.; Arbit, R. M.; Lynch, B. L.; Kiprof, P. J. Org. Chem.
1998, 63, 6590.
As illustrated in Table 2, the reactivity profile of the sub-
stituted ketones was remarkable. The reaction was equally
facile with all aromatic ketones irrespective of whether
they contain electron-withdrawing or electron-donating
substituents (entries 1–8) and 2-acetylfuran (entry 9). The
cyclic ketone cyclohexanone and aliphatic ketones in-
cluding acetone, diethyl ketone (entries 10–12), and 1,3-
dicarbonyl compounds including benzoylacetone, acetyl-
acetone, ethyl benzoylacetate underwent a-sulfonyloxyla-
tion smoothly with good to high yields (entries 13–15).
Esters such as ethyl butyrate and ethyl phenylacetate did
not react under the optimized reaction conditions.
(3) Reviews: (a) Moriarty, R. M.; Vaid, R. K.; Koser, G. F.
Synlett 1990, 365. (b) Koser, G. F. Aldrichimica Acta 2001,
34, 89. (c) Prakash, O.; Saini, N.; Sharma, P. K.
Heterocycles 1994, 38, 409. Papers: (d) Neilands, O.;
Karele, B. J. Org. Chem. USSR 1970, 6, 885. (e) Koser, G.
F.; Wettach, R. H.; Troup, J. M.; Bertram, A. F. J. Org.
Chem. 1976, 41, 3609. (f) Koser, G. F.; Wettach, R. H. J.
Org. Chem. 1977, 42, 1476. (g) Koser, G. F.; Wettach, R.
H.; Smith, C. S. J. Org. Chem. 1980, 45, 1543. (h) Koser,
G. F.; Relenyi, A. G.; Kalos, A. N.; Rebrovic, L.; Wettach,
R. H. J. Org. Chem. 1982, 47, 2487. (i) Moriarty, R. M.;
Penmasta, R.; Awasthi, A. K.; Epa, W. R.; Prakash, I. J. Org.
Chem. 1989, 54, 1101. (j) Moriarty, R. M.; Vaid, R. K.;
Hopkins, T. E.; Vaid, B. K.; Prakash, O. Tetrahedron Lett.
1990, 31, 201. (k) Tuncay, A.; Dustman, J. A.; Fisher, G.;
Tuncay, C. I. Tetrahedron Lett. 1992, 33, 7647.
In conclusion, it has been shown that hypervalent iodine
(l5) reagents in combination with organosulfonic acids
are suitable for direct a-organosulfonyloxylation. The
general applicability of the reaction was demonstrated by
using DMP in combination with p-toluenesulfonic acid
and methanesulfonic acid. Direct a-tosyloxylation and a-
mesyloxylation of various carbonyl compounds has been
achieved. The method is clean, efficient, and useful for a
wide range of carbonyl compounds.
(l) Moriarty, R. M.; Vaid, B. K.; Duncan, M. P.; Levy, S. G.;
Prakash, O.; Goyal, S. Synthesis 1992, 845. (m) Prakash,
O.; Goyal, S. Synthesis 1992, 629. (n) Prakash, O.; Rani, N.;
Goyal, S. J. Chem. Soc., Perkin Trans. 1 1992, 707.
(o) Prakash, O.; Saini, N.; Sharma, P. K. Synlett 1994, 221.
(p) Varma, R. S.; Kumar, D.; Liesen, P. J. J. Chem. Soc.,
Perkin Trans. 1 1998, 4093. (q) Lee, J. C.; Choi, J.-H.
Synlett 2001, 234. (r) Moriarty, R. M.; Vaid, B. K.; Duncan,
M. P.; Levy, S. G.; Prakash, O.; Goyal, S. Synthesis 1992,
845. (s) Nicolaou, K. C.; Mantagnon, T.; Ulven, T.; Baren,
P. S.; Zhong, Y. L.; Sarabia, F. J. Am. Chem. Soc. 2002, 124,
5718.
Acknowledgment
The authors wish to thank the University Grants Commission
(UGC), and AICTE India, for financial support.
References and Notes
(1) (a) Lodaya, J. S.; Koser, G. F. J. Org. Chem. 1988, 53, 210.
(b) Moriarty, R. M.; Vaid, R. K.; Ravikumar, V. T.; Vaid, B.
K.; Opkins, T. E. Tetrahedron 1988, 44, 1603. (c)Moriarty,
R. M.; Prakash, O. Acc. Chem. Res. 1986, 19, 244.
(d) Mizukami, E.; Ando, M.; Tanaka, T.; Imamura, J. Bull.
Chem. Soc. Jpn. 1978, 51, 335. (e) Koser, G. F.; Lodaya, J.
S.; Ray, D. G. III; Kokil, P. B. J. Am.Chem. Soc. 1988, 110,
2987.
(4) (a) Bhalerao, D. S.; Mahajan, U. S.; Chaudhari, K. H.;
Akamanchi, K. G. J. Org. Chem. 2007, 73, 662. (b) Arote,
N. D.; Bhalerao, D. S.; Akamanchi, K. G. Tetrahedron Lett.
2007, 48, 5661. (c) Ramnarayanan, G. V.; Shukla, V. G.;
Akamanchi, K. G. Synlett 2002, 2059. (d) Shukla, V. G.;
Salgaonker, P. D.; Akamanchi, K. G. J. Org. Chem. 2003,
(2) (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic Press: London, 1997. (b) Zhdankin, V. V.; Stang,
P. J. Chem. Rev. 2002, 102, 2523. (c) Zhdankin, V. V. Curr.
Synlett 2008, No. 7, 987–990 © Thieme Stuttgart · New York

990
U. S. Mahajan, K. G. Akamanchi
LETTER
68, 5742. (e) Chaudhari, S. S.; Akamanchi, K. G. Synthesis
1999, 760. (f) Chaudhari, S. S.; Akamanchi, K. G.
Tetrahedron Lett. 1998, 39, 3209.
sulfonate (Entry 4)
Solid; mp 137 °C (lit.6g 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) ppm.
2-Oxo-2-p-tolylethyl 4-Methylbenzenesulfonate (Entry
5)
(5) Review: (a) Moriarty, R. M.; Vaid, R. K.; Koser, G. F.
Synlett 1990, 365. (b) Tuncay, A.; Dustman, J. A.; Fisher,
G.; Tuncay, C. I. Tetrahedron Lett. 1992, 33, 7647.
(c) Vrama, R. S.; Kumar, D.; Liesen, P. J. J. Chem. Soc.,
Perkin Trans. 1 1998, 4093. (d) Lee, J. C.; Choi, J.-H.
Synlett 2001, 234. (e) Nabana, T.; Togo, H. J. Org. Chem.
2002, 67, 4362.
(6) (a) Yusubov, M. S.; Wirth, T. Org. Lett. 2005, 7, 519.
(b) Lee, J. C.; Choi, J.-H. Synlett 2001, 234. (c) Ueno, M.;
Nabana, T.; Togo, H. J. Org. Chem. 2003, 68, 6424.
(d) Yamamoto, Y.; Togo, H. Synlett 2006, 798. (e) Abe, S.;
Sakurantani, K.; Togo, H. Synlett 2001, 22. (f) Richardson,
R. D.; Page, T. K.; Altermann, S.; Paradine, S. M.; French,
A. N.; Wirth, T. Synlett 2007, 538. (g) Khanna, M. S.; Garg,
C. P.; Kapoor, R. P. Tetrahedron Lett. 1992, 33, 1495.
(h) Oliver, R. S.; John, N. M.; Killeen, D. A.; Sze, C. Y.;
Mark, C. B.; Nicholas, C. O. T. Org. Lett. 2007, 9, 4009.
(7) General Experimental Procedure for a-Organo-
sulfonyloxylation
Solid; mp 80 °C (lit.6g 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) ppm.
2-Oxo-2-p-tolylethyl Methanesulfonate (Entry 5)
IR (KBr): nmax = 1710 cm–1. 1H NMR (60 MHz, CDCl3): d =
2.44 (s, 3 H), 3.28 (s, 3 H), 5.48 (s, 2 H), 7.28 (d, J = 8.33
Hz, 2 H), 7.77 (d, J = 8.33 Hz, 2 H) ppm. 13C NMR (300
MHz, CDCl3): d = 190.68, 145.65, 130.93, 129.77, 127.86,
70.22, 39.27, 21.83. Anal. Calcd (%) for C10H12O4S: C,
52.63; H, 5.26. Found: C, 52.64; H, 5.25.
2-(4-Methoxyphenyl)-2-oxo-ethyl Methanesulfonate
(Entry 6)
Solid; mp 98 °C. IR (KBr): nmax 1710 cm–1. 1H NMR (60
MHz, CDCl3): d = 3.22 (s, 3 H), 3.88 (s, 3 H), 5.44 (s, 2 H),
To a stirred suspension of Dess–Martin periodinane (3.5 g,
7.5 mmol) and organosulfonic acid (10 mmol) in MeCN (15
mL) was added the substrate (5 mmol) in one portion and the
reaction mixture was refluxed until complete consumption
of starting material (monitored by TLC). After completion of
reaction MeCN was removed under reduced pressure. The
residue obtained was diluted by adding CHCl3 (50 mL) and
washed with sat. solutions of NaHCO3 (2 × 30 mL) and brine
(50 mL). The organic layer was dried over anhyd Na2SO4
and concentrated under reduced pressure to give the crude a-
organosulfonyloxylated product. Pure product was obtained
after column chromatography (SiO2, mesh size 60–120,
eluent, EtOAc–hexane, 15:85).
7.28 (d, J = 7.8 Hz, 2 H), 7.74 (d, J = 7.8 Hz, 2 H) ppm. 13
C
NMR (300 MHz, CDCl3): d = 37.63, 70.35, 55.82, 114.24,
126.81, 129.86, 165.12, 190.92. Anal. Calcd (%) for
C10H12O5S: C, 49.18; H, 4.91. Found: C, 49.20; H, 4.92.
2-[2-Chloro-4 (4-chlorophenoxy)phenyl]-2-oxo-ethyl
Methanesulfonate (Entry 7)
White solid; mp 118–119 °C. IR (KBr): nmax = 1715 cm–1. 1H
NMR (60 MHz, CDCl3): d = 3.20 (s, 3 H), 5.44 (s, 2 H),
7.20–7.89 (m, 7 H) ppm. 13C NMR (300 MHz, CDCl3): d =
39.23, 73.64, 117.32, 121.62, 123.35, 124.14, 130.70,
130.73, 131.31, 132.32, 132.40, 158.12, 190.40. Anal. Calcd
(%) for C15H13Cl2O5S: C, 47.87; H, 3.45. Found: C, 47.86;
H, 3.42.
(8) Spectroscopic Data for Selected of a-Tosyloxylated and
a-Mesyloxylated Products
1-Oxo-1-phenylpropan-2-yl 4-Methanebenzenesulfonate
(Entry 8)
2-Oxo-2-phenylethyl-4-Methanebenzenesulfonate
(Entry 1)
Solid; mp 68 °C (lit.6g 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), 7.60 (t, J = 7.2 Hz,
1 H), 7.75 (d, J = 7.2 Hz, 2 H), 7.88 (d, J = 8.1 Hz, 2 H) ppm.
2-(Furan-2-yl)-2-oxo-ethyl 4-Methanebenzensulfonate
(Entry 9)
Solid; mp 90 °C (lit.5d 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), 7.23–7.88 (m, 5 H) ppm.
2-Oxo-2-phenylethyl Methanesulfonate (Entry 1)
Solid; mp 76–77 °C (lit.1a 76–78 °C). IR (KBr): nmax = 1725
cm–1. 1H NMR (60 MHz, CDCl3): d = 3.20 (s, 3 H), 5.43 (s,
2 H), 7.12–8.12 (m, 5 H) ppm.
Solid; mp 62 °C (lit.5e 65–67 °C). IR (KBr): nmax = 1670
cm–1. 1H NMR (60 MHz, CDCl3): d = 3.27 (s, 3 H), 5.53 (s,
1 H), 7.28–8.05 (m, 3 H) ppm.
2-Oxo-cyclohexyl 4-Methylbenzenesulfonate (Entry 10)
Solid; mp 76 °C (lit.5e 74–76 °C). IR (KBr): nmax = 1744
cm–1. 1H NMR (60 MHz, CDCl3): d = 1.30–2.70 (m, 11 H),
4.82 (s, 1 H), 7.10 (d, 2 H), 8.02 (d, 2 H) ppm.
2-Oxo-propyl Methanesulfonate (Entry 11)
Oil.1a IR (neat): nmax = 1738, 1367, 1187 cm–1. 1H NMR (60
MHz, CDCl3): d = 2.20 (s, 3 H), 3.16 (s, 3 H), 4.37 (s, 2 H)
ppm.
2-(4-Chlorophenyl)-2-oxo-ethyl 4-Methanebenzene-
sulfonate (Entry 2)
Solid; mp 123 °C (lit.6g 125 °C). IR (KBr): 1190, 1360, 1700
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) ppm.
2-(2,4-Dichlorophenyl)-2-oxo-ethyl Methanesulfonate
(Entry 3)
Solid; mp 87 °C. IR (KBr): nmax = 1710 cm–1. 1H NMR (60
MHz, CDCl3): d = 3.24 (s, 3 H), 5.44 (s, 2 H), 7.22–7.83 (m,
3 H) ppm. 13C NMR (300 MHz, CDCl3): d = 37.65, 69.83,
128.90, 129.92, 130.46, 131.63, 136.10, 136.57, 190.74.
Anal. Calcd (%) for C9H8Cl2O4S: C, 38.16; H, 2.82. Found:
C, 38.15; H, 2.81.
Ethyl 2-(Methylsulfonyloxy)-3-oxo-3-phenylpropanoate
(Entry 15)
Yellow oil.1a IR (KBr): nmax = 1670 cm–1. 1H NMR (60 MHz,
CDCl3): d = 1.13 (t, 3 H), 3.23 (s, 3 H), 4.24 (q, 2 H), 6.23
(s, 1 H), 7.23–8.20 (m, 5 H) ppm.
2-(4-Nitrophenyl)-2-oxo-ethyl 4-Methanebenzene-
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