Facile deprotection of 1,3-oxathiolanes to carbonyl compounds with O-iodoxy benzoic acid (IBX) in the presence of β-cyclodextrin in water

Article abstract of DOI:10.1080/00397910600947866

1,3-Oxathiolanes are smoothly deprotected to carbonyl compounds by IBX at room temperature with β-cyclodextrin as a catalyst and water as solvent. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910600947866

Synthetic Communicationsw, 36: 3771–3775, 2006
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910600947866
Facile Deprotection of 1,3-Oxathiolanes
to Carbonyl Compounds with O-Iodoxy
Benzoic Acid (IBX) in the Presence
of b-Cyclodextrin in Water
M. Somi Reddy, M. Narender, A. Mahesh, Y. V. D. Nageswar,
and K. Rama Rao
Organic Chemistry Division I, Indian Institute of Chemical Technology,
Hyderabad, India
Abstract: 1,3-Oxathiolanes are smoothly deprotected to carbonyl compounds by IBX
at room temperature with b-cyclodextrin as a catalyst and water as solvent.
Keywords: b-Cyclodextrin, deprotection, IBX, oxathiolanes, water
INTRODUCTION
The pioneering work of Lynch and Eliel[1] and others[2] has clearly established
the utility of 1,3-oxathiolane as acyl anion equivalent for carbon–carbon bond
formation[3] and elegant synthesis of chiral alcohols. Many methods are
available for the deprotection of oxathiolanes. Usual methods of deprotection
involve stoichiometric amounts of oxidants,[1,4] chloramine-T,[4c] and
TMSOTf alone[5] or in the presence of p-nitrobenzaldehyde,[6] NCS-
AgNO3,[7] and I2-AgNO2.[8]
Among hypervalent iodine reagents, O-iodoxybenzoic acid (IBX)
has become the reagent of choice because of its easy handling, stability,
Received in India May 5, 2006
IICT Communication No. 060424.
Address correspondence to K. Rama Rao, Organic Chemistry Division I, Indian
Institute of Chemical Technology, Hyderabad, India. E-mail: ramaraok@iict.res.in
3771

3772
M. S. Reddy et al.
tolerance to moisture, and zero toxic-waste generation. The significant
utilization of IBX as a reagent is of recent origin, because of its insolubi-
lity in most solvents. However, our efforts to utilize IBX in water
under supramolecular catalysis involving cyclodextrins have further
enhanced the utility of IBX as an environmentally friendly oxidizing
agent.[9]
RESULTS AND DISCUSSION
We report herein the deprotection of a variety of 1,3-oxathiolanes with IBX
(Scheme 1) catalyzed by b-cyclodextrin (b-CD) in water to yield the corre-
sponding aldehydes or ketones.
These reactions were carried out by dissolving a catalytic amount of
b-CD (0.1 mmol of CD per 1 mmol of the substrate) in water at room
temperature followed by the addition of the substrate and IBX and then
stirring at room temperature until the reaction was complete (Table 1).
The organic material was extracted with ethyl acetate, dried, concentrated
under reduced pressure, purified by chromatography, and identified by com-
parison with authentic samples.[10] This methodology also tolerates other
functionalities: methoxy, methylenedioxy, C55C bond, and phenolic
hydroxyl. The reaction goes smoothly at room temperature with a
catalytic amount of b-CD. The catalyst can be recovered and reused. The
role of b-CD appears to be to activate the substrate by the formation of
hydrogen bonding. The reaction was very slow (6 h) in the absence of
b-CD and in the presence of IBX alone under the same reaction conditions,
and gave poor yields (,20%).
In summary, this methodology describes a simple, convenient, and highly
efficient method for the deprotection of 1,3-oxathiolanes with IBX. The
notable features of this method are cleaner reaction profiles, high yields,
and operational simplicity.
Scheme 1.

Deprotection of 1,3-Oxathiolanes
3773
Table 1. Deprotection of oxathiolanes with IBX in the presence of b-CD in water
Entry
1
Substrate
Producta
Time (min) Yield (%)b
15
90
2
3
4
5
18
88
20
18
20
20
89
90
87
85
6
7
25
86
8
20
25
25
88
85
87
9
10
11
12
18
20
90
90
(continued)

3774
M. S. Reddy et al.
Table 1. Continued
Entry
15
Substrate
Producta
Time (min) Yield (%)b
25
90
16
17
20
90
20
25
87
89
18
19
25
90
aAll products were identified by IR, NMR, and mass spectroscopy.
bYield of products isolated after column chromatography.
EXPERIMENTAL
Materials
All reactions were carried out without any special precautions in an atmos-
phere of air. Chemicals and solvents were purchased from Fluka and S. D.
1
Fine Chemicals and used as received. H NMR spectra were obtained on a
Gemini 200- or 300-MHz spectrometer, IR spectra were recorded on a
Nicolet FT-IR spectrometer, and mass spectra were obtained on a V. G.
autospectrometer.
General Procedure
The substrate (1 mmol) in acetone (1 mL), followed by IBX (1 mmol), was
added to a solution of b-cyclodextrin (0.1 mmol) in distilled water (15 mL)
at room temperature. The reaction mixture was stirred at room temperature

Deprotection of 1,3-Oxathiolanes
3775
for the specified time (Table 1), and then the product was extracted with ethyl
acetate (3 Â 15 mL). The organic phase was dried over anhydrous sodium
sulphate and concentrated under vacuum. The crude product thus obtained
was purified by column chromatography on silica gel (60–120 mesh) using
ethyl acetate–hexane as eluent.
ACKNOWLEDGMENT
M. S. R., M. N. and A. M. thank to CSIR, New Delhi, India, for financial
assistance.
REFERENCES
1. (a) Lynch, J. E.; Eliel, E. L. J. Am. Chem. Soc. 1984, 106, 2943; (b) Eliel, E. L.;
Morris-Natsche, S. S. J. Am. Chem. Soc. 1984, 106, 2937.
2. Utimoto, K.; Nakamura, A.; Motsubara, S. J. Am. Chem. Soc. 1990, 112, 8189.
3. (a) Fuji, K.; Ueda, M.; Fujita, E. J. Chem. Soc., Chem. Commun. 1977, 814;
(b) Fuji, K.; Udea, M.; Sumi, K.; Kaziwara, K.; Fujita, E.; Iwashita, T.;
Miura, I. J. Org. Chem. 1985, 50, 657; (c) Fuji, K.; Udea, M.; Sumi, K.;
Fujita, E. Tetrahedron Lett. 1981, 22, 2005; (d) Fuji, K.; Udea, M.; Fujita, E.
J. Chem. Soc., Chem. Commun. 1983, 49.
4. (a) Perrier, H.; Huyer, G.; Young, R. N. Tetrahedron Lett. 1992, 33, 725;
(b) Barton, D. H. R.; Magnus, P. D.; Smith, G.; Streckert, G.; Zurr, D. J. Chem.
Soc., Perkin Trans. 1 1972, 542; (c) Fuji, K.; Ichikawa, K.; Fujitha, E. Tetrahedron
Lett. 1978, 3561; (d) Emerson, D. W.; Wynberg, H. Tetrahedron Lett. 1971, 3445;
(e) Mandai, T.; Takeshita, M.; Kawada, M.; Otera, J. Chem. Lett. 1984, 1259.
5. Ravindranathan, T.; Chavan, S. P.; Dantale, S. W. Tetrahedron Lett. 1995, 36,
2285.
6. (a) Ravindranathan, T.; Chavan, S. P.; Tejwani, R. B.; Varghese, J. P. J. Chem.
Soc., Chem. Commun. 1991, 1750; (b) Ravindranathan, T.; Chavan, S. P.;
Varghese, J. P.; Dantale, S. W.; Tejwani, R. B. J. Chem. Soc., Chem. Commun.
1994, 1937.
7. (a) Frye, S. V.; Eliel, E. L. Tetrahedron Lett. 1985, 26, 3907; (b) Eliel, E. L.;
Soai, K. Tetrahedron Lett. 1981, 21, 2859.
8. (a) Nishide, K.; Yokota, K.; Nakamura, D.; Sumiya, T.; Node, M.; Ueda, M.;
Fuji, K. Tetrahedron Lett. 1993, 34, 3425; (b) Nishide, K.; Yokota, K.;
Nakamura, D.; Sumiya, T.; Node, M.; Ueda, M.; Fuji, K. Heterocycles 1997,
44, 393.
9. (a) Surendra, K.; Krishnaveni, N. S.; Reddy, M. A.; Nageswar, Y. V. D.; Rao, K. R.
J. Org. Chem. 2003, 68, 9119; (b) Surendra, K.; Krishnaveni, N. S.; Reddy, M. A.;
Nageswar, Y. V. D.; Rao, K. R. J. Org. Chem. 2003, 68, 2058;
(c) Krishnaveni, N. S.; Surendra, K.; Nageswar, Y. V.D.; Rao, K. R. Synthesis
2003, 1968; (d) Krishnaveni, N. S.; Surendra, K.; Somi Reddy, M.;
Nageswar, Y. V. D.; Rao, K. R. Adv. Synth. Catal. 2004, 346, 395; (e) Somi
Reddy, M.; Narender, N.; Rao, K. R. Synlett 2005, 3, 489.
10. Behnka, C. J. P. T. (Ed.). The Aldrich Library of IR, 13C and 1H FT NMR Spectra;
Aldrich: Milwaukee, WI, USA, 1985–1989.