An efficient approach to deoximation using hexachlorodisilane under mild conditions

Article abstract of DOI:10.1134/S1070363214110267

A simple, facile, and efficient procedure for deoximation of oximes to the corresponding ketones and aldehydes with hexachlorodisilane (Si₂Cl₆) in the presence of SiO₂ from good to high yields is described. Apparently, SiO₂ greatly increases the reaction rate and product yield. The proposed procedure is more advantageous than those described previously due to its higher efficiency, milder reaction conditions, shorter reaction, and easier work-up.

Full text of DOI:10.1134/S1070363214110267

ISSN 1070-3632, Russian Journal of General Chemistry, 2014, Vol. 84, No. 11, pp. 2200–2204. © Pleiades Publishing, Ltd., 2014.
An Efficient Approach to Deoximation Using Hexachlorodisilane
under Mild Conditions1
Liyong Du, Jing Gao, Shuyang Yang, Dawei Wang, Xinxin Han, Yongjian Xu, and Yuqiang Ding
Key Laboratory of Food Colloids and Biotechnology, Ministry of Education,
School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122 Jiangsu, China
e-mail: wangdw@jiangnan.edu.cn; yding@jiangnan.edu.cn
Received June 26, 2014
Abstract—A simple, facile, and efficient procedure for deoximation of oximes to the corresponding ketones
and aldehydes with hexachlorodisilane (Si2Cl6) in the presence of SiO2 from good to high yields is described.
Apparently, SiO2 greatly increases the reaction rate and product yield. The proposed procedure is more
advantageous than those described previously due to its higher efficiency, milder reaction conditions, shorter
reaction, and easier work-up.
Keywords: deoximation, oximes, hexachlorodisilane, ketones, aldehydes
DOI: 10.1134/S1070363214110267
Regeneration of carbonyl compounds from stable
and readily obtainable oximes, semicarbazones, and
hydrazones has received extensive attention in recent
decades [1–7]. Since oximes are prepared from a
variety of basic organic compounds such as primary
aliphatic amines [8], olefins [9], esters [10], nitriles
[10], nitro compounds [11], and alcohols [12],
regeneration of carbonyl compounds from oximes may
be a convenient alternative method for the preparation
of either aldehydes or ketones. Thus far, various deoxi-
mation methods based on acid-catalyzed hydrolysis
[13–16], reductive cleavage [17], oxidative cleavage
[18–28], and photosensitized oxidative deprotection
[29–31] have been developed. However, these methods
involve either highly poisonous or dangerous reagents,
as well as expensive or difficultly accessible metal
catalysts. Therefore, development of more appropriate
reagents for this kind of reaction is particularly
important. Silicon-based reagents have emerged as
synthetically useful reagents and intermediates that
provide a range of possibilities for the efficient
preparation of organic molecules [32–34]. In parti-
cular, hexachlorodisilane shows admirable properties
in various reactions, most significantly in the reduction
of phosphorus–oxygen [35], phosphorus–sulfur [35],
sulfur–oxygen [36], carbon–oxygen [37], and
nitrogen–oxygen [38] double bonds.
Accordingly, our interest herein is focused on the
use of Si2Cl6 in combination with SiO2 for the regene-
ration of certain aldehydes and ketones from oximes.
This work was aimed at developing a simple method
for the effective cleavage of the carbon–nitrogen
double bond of oximes under mild and heterogeneous
conditions (Scheme 1). The results showed that oximes
are converted into the corresponding carbonyl com-
pounds in good to excellent yields.
We began our investigation by performing the
deoximation of acetophenone oxime (Ia, R′ = Me) by
the action of Si2Cl6 in anhydrous THF in the presence
of SiO2, followed by addition of water. Hexachloro-
disilane was added in slight excess to a suspension of
Ia and SiO2 in THF. The mixture was refluxed for 8 h,
and water was then added. The mixture was stirred for
30 min to obtain acetophenone (IIa) in 95% yield. The
reaction conditions were optimized with respect to the
Scheme 1.
OH
N
O
(1) Si2Cl6, SiO2, toluene
R'
R'
(2) H2O
R
R
1 The text was submitted by the authors in English.
Ia
IIa
2200

AN EFFICIENT APPROACH TO DEOXIMATION USING HEXACHLORODISILANE
2201
Table 2. Study of the reaction scopea
Table 1. Optimization of the reaction conditionsa
OH
N
OH
N
O
O
(1) Si2Cl6, SiO2, reflux
(1) Si2Cl6, SiO2, toluene
Me
R'
Me
R'
(2) H2O
(2) H2O
R
R
Ia
Solvent
IIa
Ia
IIa
Yield,c
%
Run
no.
Si2Cl6, SiO2, H2O,
Yield,b
%
Time,
h
Productb
Time, h
Run no.
R/R′
mL
0.0
0.5
1.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
g
mL
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.2
0.1
0.0
0.2
0.2
0.2
0.2
0.2
0.2
1
2
3
4
5
6
7
8
9
THF
THF
THF
THF
THF
THF
THF
THF
THF
5.0
5.0
5.0
5.0
2.5
1.5
0.0
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
18
18
3
0
70
91
92
91
77
54
90
47
0
1
2
H/Me (Ia)
1.0
3.0
4.0
1.0
0.5
3.0
3.0
0.5
0.5
8.0
8.0
0.5
8.0
0.5
1.0
4.0
0.5
0.5
0.5
1.0
IIa
IIb
IIc
IId
IIe
IIf
95
55
4-NO2/Me (Ib)
3-NO2/Me (Ic)
4-Me/Me (Id)
4-OMe/Me (Ie)
2-Cl /Me (If)
3-Cl/Me (Ig)
4-Cl/Me (Ih)
4-F/Me (Ii)
3
>99
87
3
4
3
5
99
3
6
50
18
3
7
IIg
IIh
IIi
40
8
92
18
18
1
9
90
10 THF
10
11
12
13
14
15
16
17
18
19
20
2-F/Me (Ij)
IIj
67
11 n-Hexane
12 PhMe
13 EtOH
14 DMSO
15 DCE
57
95
31
48
<l0
<l0
H/Ph (Ik)
IIk
IIl
>99
>99
30
1
4-F/Ph (Il)
1
2-F/Ph (Im)
H/H (In)
IIm
IIn
IIo
IIp
IIq
IIr
IIs
IIt
1
>99
49
1
4-NO2/H (Io)
3-NO2/H (Ip)
4-OH/H (Iq)
4-OMe/H (Ir)
4-Me/H (Is)
4-N(Me)2/H (It)
16 DMF
1
95
a
Reaction conditions: Ia (2.5 mmol), solvent (5 mL).
Yields of isolated products.
98
b
>99
97
amounts of Si2Cl6, SiO2, and H2O (relative to 2.5
mmol of Ia), reflux time, and solvent; the results are
summarized in Table 1.
60
a
b
c
Reaction conditions: I (2.5 mmol), Si2Cl6 (1 mL), SiO2 (2.5 g),
toluene (5 mL), reflux (110°C), H2O (0.2 mL).
All products were characterized by 1H NMR spectra and by
comparison with published data.
It is seen that Si2Cl6 is necessary for the reaction to
occur (Table 1, run no. 1), but the yield increases
gradually when redundant Si2Cl6 is added (run nos. 3,
4). Addition of SiO2 dramatically shortens the reaction
time and simultaneously improves the product yield
(run nos. 3, 5–7). An effort was made to elucidate the
origin of the C=O oxygen atom in IIa. For this
purpose, H2O was intentionally omitted (run no. 10); in
this case, no deoximation was observed. As follows
from the results of run nos. 1 and 7, the oxygen atom
Yields of isolated products.
originates from H2O, as opposed to SiO2 or Ia. Scheme 2
illustrates a probable reaction mechanism.
Notably, solvent plays a significant role in increase-
ing the yield (run nos. 8, 11–16). Tetrahydrofuran and
toluene ensured similar results, but ultimately we
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 11 2014

2202
LIYONG DU et al.
Scheme 2.
O
O
OH
N
Si2Cl5
N
Si2Cl5
N
Si2Cl6
SiO2
OH2
−HCl
OH2
I
B
A
O
OH
O
HN
Si2Cl5
−H+
OH
II
chose toluene as optimum solvent with a view to
CDCl3; the chemical shifts were measured relative to
the residual proton signal of the solvent (CHCl3, δ
7.26 ppm). All solvents were purified and dried according
to standard procedures unless otherwise stated.
achieving a shorter reflux time (run nos. 8, 12). To
investigate the scope of this reaction, various aromatic
oximes Ia–It were subjected to deoximation under the
optimized reaction conditions (Table 2).
Typical procedure for the deoximation of oximes.
A mixture of 0.378 g (2.5 mmol) of acetophenone oxime
(Ia), 1.5 g (5.5 mmol) of Si2Cl6, and 2.5 g (41.7 mmol)
of SiO2) in 5 mL of toluene was heated for 1 h under
reflux (110°C). Water, 0.2 g (11.1 mmol), was then
added, and the resulting mixture was stirred for
30 min. When the reaction was complete, the mixture
was cooled to room temperature and extracted with
methylene chloride (3 × 20 mL). The combined
extracts were washed with water (25 mL), dried over
anhydrous MgSO4, filtered, and concentrated under
reduced pressure. The residue was purified by column
chromatography on silica gel (EtOAc–petroleum ether,
1 : 50 by volume) to isolate the desired product,
acetophenone (IIa) [39]. Yield 285 mg (95%), light
Regarding aromatic oximes I, both electronic
nature and steric requirements of the substituents on
the benzene ring influenced the reaction yield. Notably,
aromatic oximes bearing strongly electron-withd-
rawing (NO2) and electron-donating groups (OMe) at
the para position of the benzene ring differed greatly
in the yields (Table 2, run nos. 2, 5, 15, 18). However,
very good efficiency was achieved in the deoximation
of meta-nitro derivatives Ic and Ip (Table 2, run nos. 3,
16). Substituents in the ortho position (Table 2, run
nos. 2, 6, 10, 13), markedly reduced the yield, which
may be due to steric reasons.
In keeping with a plausible mechanism shown in
Scheme 2, aromatic oxime I initially reacts with Si2Cl6
to form intermediate A. The subsequent reaction of
intermediate A with water generates intermediate B
which undergoes electron and proton transfer to
produce final product II.
1
yellow oil. H NMR spectrum, δ, ppm: 7.97–7.95 m
(2H), 7.58–7.54 m (1H), 7.48–7.44 m (2H), 2.61 s
(3H).
4-Nitroacetophenone (IIb) [39]. Yield 227 mg
1
(55%), light yellow crystals, mp 75–78°C. H NMR
In summary, we have developed a straightforward,
facile, and efficient procedure for deoximation of
oximes to the corresponding ketones and aldehydes
with good to excellent yields. The main advantages of
the proposed method are milder reaction conditions,
shorter reaction times, and easier workup.
spectrum, δ, ppm: 8.33–8.30 m (2H), 8.13–8.10 m
(2H), 2.68 s (3H).
3-Nitroacetophenone (IIc) [39]. Yield 411 mg
1
(>99%), light yellow solid, mp 76–78°C. H NMR
spectrum, δ, ppm: 8.77 d (1H, J = 2.0 Hz), 8.44–8.41
m (1H), 8.30–8.28 m (1H), 7.71–7.67 m (1H), 2.69 s
(3H).
EXPERIMENTAL
1
The H NMR spectra were recorded on a Bruker
4-Methylacetophenone (IId) [39]. Yield 291 mg
(87%), colorless liquid. H NMR spectrum, δ, ppm:
1
ACF-400 spectrometer (400 MHz) from solutions in
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 11 2014

AN EFFICIENT APPROACH TO DEOXIMATION USING HEXACHLORODISILANE
2203
7.85 d (2H, J = 8 Hz), 7.25 d (2H, J = 8 Hz), 2.57 s
(3H), 2.41 s (3H).
3-Nitrobenzaldehyde (IIp) [41]. Yield 359 mg
(95%), light yellow solid, mp 55–58°C. H NMR
1
spectrum, δ, ppm: 10.19 s (1H), 8.73 s (1H), 8.50 s
(1H), 8.27 s (1H), 7.80 s (1H).
4-Methoxyacetophenone (IIe) [39]. Yield 371 mg
(99%), colorless crystals, mp 36–38°C. 1H NMR spec-
trum, δ, ppm: 7.93 d (2H, J = 8.8 Hz), 6.92 d (2H, J =
8.8 Hz), 3.86 s (3H), 2.54 s (3H).
4-Hydroxybenzaldehyde (IIq) [41]. Yield 299 mg
1
(98%), light yellow crystals, mp 114–117°C. H NMR
spectrum, δ, ppm: 9.87 s (1H), 7.82 d (2H, J = 6.8 Hz),
6.97 d (2H, J = 7.2 Hz), 6.73 br s (1H).
2-Chloroacetophenone (IIf) [39]. Yield 193 mg
(50%), colorless oily liquid. 1H NMR spectrum, δ, ppm:
7.56–7.53 m (1H), 7.41–7.30 m (3H), 2.64 s (3H).
4-Methoxybenzaldehyde (IIr) [41]. Yield 339 mg
1
(>99%), colorless liquid. H NMR spectrum, δ, ppm:
3-Chloroacetophenone (IIg) [39]. Yield 154 mg
(40%), colorless oil. 1H NMR spectrum, δ, ppm: 7.93–
7.92 m (1H), 7.84–7.82 m (1H), 7.55–7.52 m (1H),
7.43–7.39 m (1H), 2.59 s (3H).
9.85 s (1H), 7.81 d (2H, J = 8.8 Hz), 6.98 d (2H, J =
8.4 Hz), 3.86 s (3H).
4-Methylbenzaldehyde (IIs) [41]. Yield 291 mg
1
(97%), colorless oily liquid. H NMR spectrum, δ,
4-Chloroacetophenone (IIh) [39]. Yield 355 mg
ppm: 9.94 s (1H), 7.76 d (2H, J = 7.6 Hz), 7.31 d (2H,
J = 8.4 Hz), 2.42 s (3H).
1
(92%), colorless oily liquid. H NMR spectrum, δ,
ppm: 7.88 d (2H, J = 8.8 Hz), 7.42 d (2H, J = 8.8 Hz),
2.58 s (3H).
4-(Dimethylamino)benzaldehyde (IIt) [41]. Yield
1
224 mg (60%), light yellow solid, mp 72–75°C. H
4-Fluoroacetophenone (IIi) [39]. Yield 310 mg
NMR spectrum, δ, ppm: 9.72 s (1H), 7.72 d (2H, J =
8.8 Hz), 6.68 d (2H, J = 8.8 Hz), 3.06 s (6H).
1
(90%), colorless liquid. H NMR spectrum, δ, ppm:
8.00–7.96 m (2H), 7.15–7.11 m (2H), 2.58 s (3H).
ACKNOWLEDGMENTS
2-Fluoroacetophenone (IIj) [39]. Yield 231 mg
(67%), colorless oily liquid. H NMR spectrum, δ,
ppm: 7.89–7.85 m (1H), 7.53–7.49 m (1H), 7.24–7.20
m (1H), 7.16–7.11 m (1H), 2.64 d (3H, J = 5 Hz).
1
We gratefully acknowledge financial support of this
work by the National Natural Science Foundation of
China (no. 21371080), 333 Talent Project of Jiangsu
Province (BRA2012165), the Fundamental Research
Funds for the Central Universities (JUDCF13016) and
the Postgraduate Innovation Project of Jiangsu
Province (CXZZ13_0746).
Benzophenone (IIk) [40]. Yield 452 mg (>99%),
1
colorless crystals, mp 47–49°C. H NMR spectrum, δ,
ppm: 7.81–7.79 m (4H), 7.61–7.57 m (2H), 7.50–7.46
m (4H).
4-Fluorobenzophenone (IIl) [40]. Yield 496 mg
(>99%), colorless crystals, mp 46–48°C. H NMR
spectrum, δ, ppm: 7.86–7.83 m (2H), 7.78–7.76 m
(2H), 7.62–7.57 m (1H), 7.50–7.47 m (2H), 7.18–7.15 m
(2H).
REFERENCES
1
1. Yang, Y.T., Li, T.S., and Li, Y.L., Synth. Commun.,
1993, vol. 23, p. 1121.
2. Khurana, J.M., Ray, A., and Sahoo, P.K., Bull. Chem.
Soc. Jpn., 1994, vol. 67, p. 1091.
3. Khan, R.H., Mathur, R.K., and Ghosh, A.C., J. Chem.
Res., Synop., 1995, p. 506.
2-Fluorobenzophenone (IIm) [40]. Yield 151 mg
1
(30%), colorless liquid. H NMR spectrum, δ, ppm:
7.85–7.83 m (2H), 7.58–7.45 m (5H), 7.28–7.25 m
(1H), 7.18–7.14 m (1H).
4. Zhang, G.S., Yang, D.H., Chen, M.F., and Cai, K.,
Synth. Commun., 1998, vol. 28, p. 607.
5. Shirini, F. and Azadbar, M.A., Synth. Commun., 2001,
Benzaldehyde (IIn) [41]. Yield 264 mg (>99%),
colorless oily liquid. 1H NMR spectrum, δ, ppm: 7.51 t
(2H, J = 7.6 Hz), 7.61 t (1H, J = 7.2 Hz), 7.86 d (2H,
J = 7.6 Hz), 9.99 s (1H).
vol. 31, p. 3775.
6. Shirini, F., Zolfigol, M.A., and Azadbar, M.R., Synth.
Commun., 2002, vol. 32, p. 315.
7. Shirini, F., Zolfigol, M.A., Mallakpour, B., Mallak-
pour, S.E., Hajipour, A.R., and Mohammadpour, B.I.,
Tetrahedron Lett., 2002, vol. 43, p. 1555.
4-Nitrobenzaldehyde (IIo) [41]. Yield 185 mg
1
(49%), light yellow crystals, mp 104–107°C. H NMR
8. Kahr, K. and Berther, C., Chem. Ber., 1960, vol. 93,
spectrum, δ, ppm: 8.09 d (2H, J = 7.2 Hz), 8.41 d (2H,
J = 6.8 Hz), 10.18 s (1H).
p. 132.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 11 2014

2204
LIYONG DU et al.
9. Kadzyauskas, P.P. and Zefirov, N.S., Russ. Chem. Rev.,
27. Grirrane, A., Corma, A., and Garcia, H., J. Catal., 2009,
1968, vol. 37, p. 543.
vol. 268, p. 350.
10. Fujisawa, T., Kurita, Y., and Sato, T., Chem. Lett., 1983,
vol. 12, p. 1537.
11. Stiver, S. and Yates, P., J. Chem. Soc., Chem. Commun.,
28. Zhang, G.F., Wen, X., Wang, Y., Han, X.W., Luan, Y.X.,
Zheng, L.B., Ding, C.G., and Cao, X.J., RSC Adv.,
2013, vol. 3, p. 22918.
1983, p. 50.
29. Saravanselvi, C., Somasundaram, N., Vijaikumar, S.,
and Srinivasan, C., Photochem. Photobiol. Sci., 2002,
vol. 1, p. 607.
12. Barton, D.H.R. and Beaton, J.M., J. Am. Chem. Soc.,
1961, vol. 83, p. 4083.
13. De, S.K., Tetrahedron Lett., 2003, vol. 44, p. 9055.
30. Lijser, H.J.P., Fardoun, F.H., Sawyer, J.R., and Quant, M.,
Org. Lett., 2002, vol. 4, p. 2325.
14. Chavan, S.P. and Soni, P., Tetrahedron Lett., 2004,
vol. 45, p. 3161.
31. Kim, B.R., Lee, H.G., Kim, E.J., Lee S. G., and Yoon, Y.J.,
15. Lee, S.Y., Lee, B.S., Lee, C.W., and Oh, D.Y., J. Org.
Chem., 2000, vol. 65, p. 256.
16. Martin, M., Martinez, G., Urpi, F., and Vilarrasa, J.,
J. Org. Chem., 2010, vol. 75, p. 484.
32. The Chemistry of Organic Silicon Compounds, Patai, S.
and Rappoport, Z., Eds., Chichester: Wiley, 1989, vol. 1,
p. 895
Tetrahedron Lett., 2004, vol. 45, p. 5559.
17. Curran, D.P., Brill, J.F., and Rakiewicz, D.M., J. Org.
Chem., 1984, vol. 49, p. 1654.
18. Davey, D.D. and Lumma, W.C., J. Org. Chem., 1989,
vol. 54, p. 3211.
19. Shinada, T. and Yoshihara, K., Tetrahedron Lett., 1995,
vol. 36, p. 6701.
20. Demir, A.S., Tanyeli, C., and Altinel, E., Tetrahedron
Lett., 1997, vol. 38, p. 7267.
33. Hiyama, T. and Kusumoto, T., Comp rehensive Organic
Synthesis, Pergamon: Oxford, 1991, p. 763.
34. The Chemistry of Organic Silicon Compounds, Patai, S.
and Rappoport, Z., Eds., Chichester: Wiley, 1998, vol. 2,
p. 919.
35. Krenske, E.H., J. Org. Chem., 2012, vol. 77, p. 1.
36. Zhang, X.W., Huang, K.X., Hou, G.H., Cao, B.N., and
Zhang, X.M., Angew. Chem., Int. Ed., 2010, vol. 49,
p. 6421.
21. Barhate, N.B., Gajare, A.S., Wakharkar, R.D., and
Sudalai, A., Tetrahedron Lett., 1997, vol. 38, p. 653.
37. Yang, J.C. and Verkade, J.G., J. Organomet. Chem.,
22. Zhang, G.-F., Wen, X., Wang, Y., Mo, W.-M., and
2002, vol. 651, p. 15.
Ding, C.-G., J. Org. Chem., 2011, vol. 76, p. 4665.
38. Naumann, K. and Gerald, Z.M., J. Am. Chem. Soc.,
23. Hashemi, M.M. and Beni, Y.A., Synth. Commun., 2001,
1969, vol. 91, p. 7012.
vol. 31, p. 295.
39. Ruan, J.W., Li, X.M., Saidi, O., and Xiao, J.L., J. Am.
Chem. Soc., 2008, vol. 130, p. 2424.
24. Yang, Y., Zhang, D., Wu, L.Z., Chen, B., Zhang, L.P.,
and Tung, C.H., J. Org. Chem., 2004, vol. 69, p. 4788.
25. Jain, N., Kumar, A., and Chauhan, S.M.S., Tetrahedron
Lett., 2005, vol. 46, p. 2599.
40. Meng, L., Su, J., Zha, Z., Zhang, L., Zhang, Z., and
Wang, Z., Chem. Eur. J., 2013, vol. 19, p. 5542.
26. Deshpande, S.S., Sonavane, S.U., and Jayaram, R.V.,
41. Ruan, J.W., Li, X.M., Saidi, O., and Xiao, J.L., J. Am.
Chem. Soc., 2008, vol. 130, p. 2424.
Catal. Commun., 2008, vol. 9, p. 639.
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