Synthesis of cyclic peroxides containing the Si-gem-bisperoxide fragment. 1,2,4,5,7,8-hexaoxa-3-silonanes as a new class of peroxides

Article abstract of DOI:10.1021/jo7027213

(Chemical Equation Presented) A method was developed for the synthesis of the previously unknown class of organic peroxides, 1,2,4,5,7,8-hexaoxa-3- silonanes, based on the reaction of dialkyldichlorosilanes with 1,1′-dihydroperoxyperoxides. 1,2,4,5,7,8-Hexaoxa-3-silonanes are rather stable under ambient conditions and were characterized by NMR spectroscopy, X-ray diffraction, and elemental analysis. Their yields are in a range of 59-96%. The attempts were made to prepare 1,2,4,5-tetraoxa-3-silinanes by the reaction of dialkyldichlorosilanes with gem-bishydroperoxides. 1,2,4,5-Tetraoxa-3-silinanes were detected by NMR spectroscopy; these compounds rapidly decompose upon isolation.

Full text of DOI:10.1021/jo7027213

Synthesis of Cyclic Peroxides Containing the Si-gem-bisperoxide
Fragment. 1,2,4,5,7,8-Hexaoxa-3-silonanes as a New Class of
Peroxides
Alexander O. Terent’ev,*,† Maxim M. Platonov,† Anna I. Tursina,‡
Vladimir V. Chernyshev,‡,§ and Gennady I. Nikishin†
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991
Moscow, Russian Federation, Department of Chemistry, Moscow State UniVersity, 119992 Moscow,
Russian Federation, and A.N. Frumkin Institute of Physical Chemistry and Electrochemistry,
31 Leninsky prosp., 119991 Moscow, Russian Federation
terenteV@ioc.ac.ru
ReceiVed December 21, 2007
A method was developed for the synthesis of the previously unknown class of organic peroxides,
1,2,4,5,7,8-hexaoxa-3-silonanes, based on the reaction of dialkyldichlorosilanes with 1,1′-dihydroperox-
yperoxides. 1,2,4,5,7,8-Hexaoxa-3-silonanes are rather stable under ambient conditions and were
characterized by NMR spectroscopy, X-ray diffraction, and elemental analysis. Their yields are in a
range of 59-96%. The attempts were made to prepare 1,2,4,5-tetraoxa-3-silinanes by the reaction of
dialkyldichlorosilanes with gem-bishydroperoxides. 1,2,4,5-Tetraoxa-3-silinanes were detected by NMR
spectroscopy; these compounds rapidly decompose upon isolation.
Introduction
are produced as intermediates in the Fleming6 or Tamao-
Kumada7 oxidation: conversion of alkyl silanes to alcohols by
means of peracids or hydrogen peroxide. However, the chem-
istry of organosilicon peroxides is less well-known due, in part,
to the fact that the methods of their synthesis are few in number.
There are several routes to peroxides containing the Si-O-O
fragment. These methods are based on the reactions of chlo-
Organic peroxides belong to a broad and highly demanded
class of compounds.1 These compounds have found wide
application in industrial and laboratory synthesis as oxidants,
polymerization initiators, cross-linking agents, building blocks,
intermediates in autoxidation, and substances having antimalarial
and antimicrobial activities. Peroxides containing the Si-O-O
fragment have similar applications. They are used primarily for
the polymerization initiation,2 hydroxylation of arenes,3 per-
oxidation,4 and in thermal transformations.5 These compounds
(2) (a) Fomin, V. A.; Petrukhin, I. V. J. Gen. Chem. USSR (Engl. Transl.)
1997, 67, 580-588 [Zh. Obshch. Khim. 1997, 67, 621-630]. (b) Terman,
L. M.; Brevnova, T. N.; Sutina, O. D.; Semenov, V. V.; Ganyushkin, A.
V. Bull. Acad. Sci. USSR DiV. Chem. Sci. (Engl.Transl.) 1980, 448-452
[IzV. Akad. Nauk SSSR Ser. Khim. 1980, 629-634].
(3) (a) Taddei, M.; Ricci, A. Synthesis 1986, 633-635. (b) Sengupta,
S.; Snieckus, V. Tetrahedron Lett. 1990, 31, 4267-4270. (c) Camici, L.;
Dembech, P.; Ricci, A.; Seconi, G.; Taddei, M. Tetrahedron 1988, 44,
4197-4206.
(4) (a) Jefford, C. W.; Rossier, J.-C.; Richardson, G. D. J. Chem. Soc.,
Chem. Commun. 1983, 1064-1065. (b) Mukaiyama, T.; Miyoshi, N.; Kato,
J.-I.; Ohshima, M. Chem. Lett. 1986, 1385-1388. (c) Ramirez, A.; Woerpel,
K. A. Org. Letters 2005, 7 (21), 4617-4620. (d) Ahmed, A.; Dussault, P.
H. Tetrahedron 2005, 61, 4657-4670. (e) Dai, P.; Dussault, P. H. Org.
Lett. 2005, 7 (20), 4333-4335. (f) Dai, P.; Trullinger, T. K.; Liu, X.;
Dussault, P. H. J. Org. Chem. 2006, 71 (6), 2283-2292.
* Corresponding author. Tel: +7 (499) 1356428. Fax: +7 (499) 1355328.
† N.D. Zelinsky Institute of Organic Chemistry.
‡ Moscow State University.
§ A.N. Frumkin Institute of Physical Chemistry and Electrochemistry.
(1) (a) Jones, C. W. Applications of Hydrogen Peroxides and DeriVatiVes;
Royal Society of Chemistry: Cambridge, 1999. (b) The chemistry of
peroxides; Patai, S., Ed.; Wiley: New York 1983. (c) Organic Peroxides;
Ando, W., Ed.; Wiley: New York, 1992. (d) Peroxide Chemistry:
Mechanistic and PreparatiVe Aspects of Oxygen Transfer; Adam, W., Ed;
Wiley-VCH: Weinheim, 2000. (e) Catalytic Oxidations with Hydrogen
Peroxide as Oxidant; Strukul, G., Ed.; Kluwer Academic Publishers:
Boston, MA, 1992.
10.1021/jo7027213 CCC: $40.75 © 2008 American Chemical Society
Published on Web 03/18/2008
J. Org. Chem. 2008, 73, 3169-3174
3169

Terent’ev et al.
SCHEME 1. Synthesis of 1,2,4,5,7,8-hexaoxa-3-silonanes
rosilanes with hydroperoxides in the presence of bases,8 singlet
oxygen with silyl enolates,9 compounds containing the Si-H
bond with ozone,10 hydroperoxides with N,O-bis(trimethylsilyl)-
acetamide,11 and the Co(L)2/O2/Et3SiH system with unsaturated
compounds.12 Mono-, di-, tri-, and tetraperoxy-substituted silanes
have been synthesized according to these methods.
Some aspects of the chemistry of organosilicon peroxides
have been reviewed by Brandes and Blaschette,13a Aleksandrov,13b
Tamao,13c Ando,13d Ricci,13e and Davies.13f An analysis of the
published data shows that no systematic studies of the properties
and reactions of cyclic peroxides containing the O-O-Si-
O-O fragment have been performed, and efficient procedures
for the synthesis of these compounds are lacking. Only a few
structures containing the O-O-Si-O-O fragment in the ring
(3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexaoxa-3,6,9-
trisilonane14a and 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxa-3-
silonane14b) were documented.
Results and Discussion
(5) (a) Yablokov, V. A.; Sunin, A. N.; Yablokova, N. V.; Ganyushkin,
A. V. J. Gen. Chem. USSR (Engl. Transl.) 1974, 44, 2405-2408 [Zh.
Obshch. Khim. 1974, 44, 2446-2449]. (b) Yablokov, V. A.; Thomadze A.
V.; Yablokova, N. V.; Aleksandrov, Yu. A. J. Gen. Chem. USSR (Engl.
Transl.) 1979, 49, 1570-1572 [Zh. Obshch. Khim. 1979, 49, 1787-1790].
(c) Sluchevskaya, N. P.; Yablokov, V. A.; Yablokova, N. V.; Savushkina
V. I.; Chernyschev E. A. J. Gen. Chem. USSR (Engl. Transl.) 1977, 47,
213 [Zh. Obshch. Khim. 1977, 47, 229].
(6) (a) Jones, G. R.; Landais, Y. Tetrahedron 1996, 52, 7599-7662. (b)
Fleming, I.; Henning, R.; Plaut, H. J. Chem. Soc., Chem. Commun. 1984,
29-31. (c) Fleming, I.; Sanderson, P. E. J. Tetrahedron Lett. 1987, 28,
4229-4232.
(7) (a) Tamao, K.; Ishida, N.; Kumada, M. J. Org. Chem. 1983, 48 (12),
2120-2122. (b) Tamao, K.; Ishida, N.; Tanaka, T.; Kumada, M. Organo-
metallics 1983, 2, 1694-1696. (c) Tamao, K.; Ishida, N. J. Organomet.
Chem. 1984, 269, C37-C39.
(8) (a) Buncel, E; Davies, A.G. J. Chem. Soc. 1958, 1550-1556. (b)
Ol’dekop, Yu. A.; Livshits, F. Z. J. Gen. Chem. USSR (Engl. Transl.) 1974,
44, 2135-2137 [Zh. Obshch. Khim. 1974, 44, 2174-2176]. (c) Brandes,
D.; Blaschette, A. Monatsh. Chem. 1975, 106, 1299-1306. (d) Fan, Y. L.;
Shaw, R. G. J. Org. Chem. 1973, 38, 2410-2412.
The aims of the present study were to examine the possibility
of the existence of 1,2,4,5-tetraoxa-3-silinanes and 1,2,4,5,7,8-
hexaoxa-3-silonanes, which belong to new classes of cyclic di-
and triperoxides containing one Si atom and two or three O-O
bonds in the ring, under ambient conditions, develop an
approach to the synthesis of such compounds, evaluate their
stability during isolation and storage, and characterize these
compounds by NMR spectroscopy. In addition, the goal was to
estimate to what extent the formation of oligomeric (linear)
peroxides competes with the cyclization.
The reactions of gem-bishydroperoxides and 1,1′-dihydrop-
eroxyperoxides with available dialkyldichlorosilanes and stan-
dard procedures for the isolation and identification of the
products were used as the general strategy for the synthesis of
the target peroxides.
Synthesis of 1,2,4,5,7,8-Hexaoxa-3-silonanes. Initially, we
examined the synthesis of 1,2,4,5,7,8-hexaoxa-3-silonanes (8-
13) based on the condensation of 1,1′-dihydroperoxyperoxides
(1-6) with dialkyldichlorosilanes (7a-h) in the presence of
bases (Scheme 1).
(9) (a) Adam, W.; Alzerreca A.; Liu J.-C.; Yany F. J. Am. Chem. Soc.
1977, 99 (17), 5768-5773. (b) Einaga, H.; Nojima, M; Abe, M. J. Chem.
Soc. Perkin Trans. 1 1999, 2507-2512. (c) Cointeaux, L.; Berrien, J. -F.;
Mahuteau, J.; Traˆn Huu-Daˆu, M. E.; Cice´ron, L.; Danis, M.; Mayrargue, J.
Bioorg. Med. Chem. 2003, 11, 3791-3794.
(10) Corey, E. J.; Mehrotra, M. M.; Khan, A. U. J. Am. Chem. Soc.
1986, 108, 2472.
When we proceeded to the synthesis of peroxides 8-13
containing a nine-membered ring, we could not be quite sure
(11) (a) Kim, H-S.; Begum, K.; Ogura, N.; Wataya, Y.; Nonami, Y.;
Ito, T.; Masuyama, A.; Nojima, M.; McCullough, K. J. J. Med. Chem. 2003,
46 (10), 1957-1961. (b) Ushigoe, Y.; Masuyama, A.; Nojima, M.;
McCullough, K. J. Tetrahedron Lett. 1997, 38, 8753-8756. (c) Kim, H.-
S.; Tsuchiya, K.; Shibata, Y.; Wataya, Y.; Ushigoe, Y.; Masuyama, A.;
Nojima, M.; McCullough, K. J. J. Chem. Soc., Perkin Trans. 1 1999, 1867-
1870.
(12) (a) Tokuyasu, T.; Kunikawa, S.; McCullough, K. J.; Masuyama,
A.; Nojima, M. J. Org. Chem. 2005, 70 (1), 251-260. (b) Tokuyasu, T.;
Kunikawa, S.; Abe, M.; Masuyama, A.; Nojima, M.; Kim, H.-S.; Begum,
K.; Wataya, Y. J. Org. Chem. 2003, 68 (19), 7361-7367. (c) Ahmed, A.;
Dussault, P. H. Org. Lett. 2004, 6 (20), 3609-3611. (d) O’Neill, P. M.;
Hindley, S.; Pugh, M. D.; Davies, J.; Bray, P. G.; Park, B. K.; Kapu, D. S.;
Ward, S. A.; Stocks, P. A. Tetrahedron Lett. 2003, 44, 8135-8138.
(13) (a) Brandes, D.; Blaschette, A. J. Organomet. Chem. 1974, 78, 1-48.
(b) Alexandrov, Yu. A. J. Organomet. Chem. 1982, 238, 1-78. (c) Tamao,
K. Science of Synthesis; Moloney, M. G. Ed.; Thieme: Stuttgart 2002. (d)
Ando, W. Chemistry of peroxides; Rappoport, Z., Ed.; John Wiley and
Sons: New York, 2006; pp 775-830. (e) Ricci, A.; Seconi, G.; Curci, R.;
Larson, G. L. AdV. Silicon. Chem. 1996, 3, 63-104. (f) Davies, A. G.
Tetrahedron 2007, 63, 10385-10405.
(14) (a) Razuvaev, G. A.; Yablokov, V. A.; Ganyushkin, A. V.;
Schklover, V. E.; Zinker, I.; Struchkov, Yu. T. Dokl. Chem. (Engl. Transl.)
1978, 242, 428-431 [Dokl. Acad. Nauk SSSR Ser. Khim. 1978, 242, 132-
135]. (b) Halle, R.; Bock, L. A. Argus. Chem. Co. US Patent 4161485,
1979; Chem. Abstr. 1980, 92, 42836.
3170 J. Org. Chem., Vol. 73, No. 8, 2008

Si-gem-bisperoxides
TABLE 1. Synthesis of Hexaoxasilonane 12a from Me2SiCl2 7aa and 1,1′-Dihydroperoxyperoxide 5 in the Presence of Different Bases
base
pyridine
DMAP
quinoline
imidazole
Et3N
DABCO
DBU
in the absence of bases
ratio, mole of base per mole of 5
reaction time, h
5
3
5
5
5 (3; 7)
3
96 (93; 96)
5
3
21
4
3
34
5
3 (1)
5 (traces)
3 (1)
94 (71)
3 (1; 17)
94 (70; 94)
3
5
yield 12a,b %
83 (85c)
a A one-and-a-half molar excess of Me2SiCl2 7a with respect to 5. b Yield based on the isolated product. c A 6-fold molar excess of Me2SiCl2 7a with
respect to 5.
that the goal would be attained. It is known that general methods
for the construction of structurally similar carbocycles containing
a nine-membered ring are not always applicable to the synthesis
of such carbocycles because of the formation of oligomers.
The procedure for the synthesis of peroxide 12a was
optimized and the influence of the reaction conditions on the
yield of the target compound was studied on the basis of the
reaction of dichlorodimethylsilane 7a with dihydroperoxyper-
oxide 5. We used the following aromatic and aliphatic nitrogen
bases: pyridine, DMAP, quinoline, imidazole, DABCO, DBU,
and triethylamine.
presence of DMAP or quinoline is 3 h. A decrease in the
reaction time from 3 to 1 h leads to a decrease in the yield of
peroxide 12a from 94 to ca. 70%.
As can be seen from Table 1, aliphatic amines, Et3N,
DABCO, and DBU are less efficient than aromatic amines. In
the presence of DABCO, dihydroperoxyperoxide 5 is decom-
posed to a considerable extent to give cyclododecanone as the
major product, whereas peroxide 12a is produced in a yield of
only 34%.
The low efficiency of triethylamine may be a consequence
of the partial decomposition of peroxide 12a. An analogous
2a
In this reaction, the base serves several functions. First, it
increases the nucleophilicity of hydroperoxide groups via proton
abstraction from dihydroperoxide. This is evident from the
effect has been observed earlier in the reaction of dimethy-
lamine with peroxides containing the Si-O-O-C fragment.
The formation of 12a is not catalyzed by DBU, and dihydro-
peroxyperoxide 5 remains virtually unconsumed. In the absence
of bases, compound 12a is produced in a yield of only 5%.
It can be assumed that the main difference in the yields of
12a with the use of aliphatic and aromatic amines results from
the specific character of their complexation with dihydroper-
oxyperoxide 5. Contrary to aromatic amines, aliphatic amines
form complexes with dihydroperoxyperoxide 5 of low reactivity,
which either decompose or react slowly with silane 7a.
Peroxides 8-13 were synthesized with the use of a 3-fold
molar excess of imidazole; silanes 7a-h, with a 1.2-fold molar
excess with respect to dihydroperoxyperoxides 1-5. Under these
conditions, peroxides 8-13 were isolated in high preparative
yields (59-94%, see Table 2).
Under these conditions, the reaction is completed in from 1
to 24 h depending on the structures of the starting reagents,
primarily, on the volume of the substituents R′ and R′′ at the
silicon atom in dichlorosilanes 7a-h. As expected, the con-
densation of peroxides 1-5 with sterically unhindered dichlo-
rodimethylsilane 7a proceeds most easily; the reaction with
dichlorodiethylsilane 7b proceeds somewhat less readily. The
rate of the reaction with dichlorodiphenylsilane 7f sharply
decreases; however, this reaction also produces peroxides 9f
and 12f in satisfactory yields (78-79%). An insignificant
amount of phenol was detected among the reaction products in
the condensation of peroxides 2 and 5 with dichlorodiphenyl-
silane 7f.
1
results of NMR experiments. The H and 13C NMR spectra of
dihydroperoxyperoxide 2 and its mixture with imidazole in a
1
molar ratio of 1:2 were recorded in CDCl3. In the H NMR
spectrum of the mixture, the signal for the protons of the OOH
groups of compound 2 (at δ 9.5) disappeared. In the 13C NMR
spectrum, the signal for the quaternary carbon atom was shifted
upfield (from δ 111.1 to δ 110).
The second function of amine in this reaction is, apparently,
to form complexes with dialkyldichlorosilane. For example, the
formation of stable complexes in the reactions of amines with
SiF4 was documented.15 The mixing of Me2SiCl2 with imidazole
affords a precipitate, and the reaction of the latter with
dihydroperoxyperoxide 5 produces 1,2,4,5,7,8-hexaoxa-3-silo-
nane 12a in 71% yield.
In addition, nitrogen bases serve as acceptors of hydrogen
chloride that is eliminated in the course of the reaction. It is
important to trap hydrogen chloride and maintain the basicity
of the medium. If these conditions are not fulfilled, 1,2,4,5,7,8-
hexaoxa-3-silonanes undergo decomposition.
The yield of peroxides depends, among other things, on the
nature of the base. The influence of this factor and other reaction
conditions was examined for the synthesis of peroxide 12a
which is characterized by high stability. The easy and reproduc-
ible procedure for the purification and isolation of peroxide 12a
allowed the precise determination of its yield (Table 1).
The highest yield of peroxide 12a was achieved in the
reactions of 5 and 7a with use of aromatic nitrogen-containing
bases. Peroxide 12a was prepared in virtually quantitative yield
(94 and 96%) in the presence of DMAP, quinoline, or imidazole;
in somewhat lower yield (83%), in the presence of pyridine.
An excess amount of a base has little effect on the formation
of peroxide 12a. In the presence of a 3-, 5-, or 7-fold molar
excess of imidazole with respect to dihydroperoxyperoxide 5,
the yield of the target product was 93, 96, and 96%, respectively.
An increase in the excess of dichlorosilane 7a from 1.5- to 6-fold
had virtually no effect on the yield of peroxide 12a. The reaction
time required for the achievement of the best result in the
The ring size in peroxides 1-5 also influences the results of
the reaction, although to a lesser extent than the structures of
the substitutes R′ and R′′ in dialkyldichlorosilanes 7a-h.
Unexpectedly, in contradiction with the steric factor, the yield
of peroxide 12a containing the 12-memebred ring appeared to
be higher than that of peroxide 8a containing the five-membered
ring. Most likely, this difference is attributed to the partial
hydrolysis of peroxide 8a in the course of chromatographic
purification on silica gel. This conclusion is consistent with the
quantitative results of the hydrolysis of hexaoxasilonanes
presented in Table 3.
Diacetoxydimethylsilane can also be used for the cyclization,
as was exemplified by the synthesis of 8a, 9a, 11a, and 12a.
These reactions produce peroxides in lower yields compared
(15) (a) Fessenden, R.; Fessenden, J. S. Chem. ReV. 1961, 361-388. (b)
Organic Silicon Compounds; Rappoport, Z., Apeloig, Y., Eds.; John Wiley
& Sons: New York, 1998; Vol. 2.
J. Org. Chem, Vol. 73, No. 8, 2008 3171

Terent’ev et al.
TABLE 2. Synthesis of 1,2,4,5,7,8-Hexaoxa-3-silonanes 8-13
a Yield based on the isolated product. b Yield of the reaction with diacetoxydimethylsilane.
to the reactions of the corresponding dihydroperoxyperoxides
with dichlorodimethylsilane 7a. Peroxides 8-13 are stable on
storage at 0 °C and can be purified by silica gel chromatography
and recrystallized from anhydrous solvents. Some of these
compounds have very high melting points, which are not typical
of peroxides; for example, the melting points of 12a and 13a
are 264-266 and 156-158 °C, respectively. At these temper-
atures, peroxides ROOR (R ) alkyl) generally undergo decom-
position accompanied by the O-O bond cleavage. A comparison
of thermal stability of 1,2,4,5,7,8-hexaoxa-3-silonanes 8a, 9a,
3172 J. Org. Chem., Vol. 73, No. 8, 2008

Si-gem-bisperoxides
TABLE 3. Hydrolysis of 1,2,4,5,7,8-Hexaoxa-3-silonanesa
SCHEME 2. Hydrolysis of 1,2,4,5,7,8-Hexaoxa-3-silonanes
time of complete
hydrolysis of
1,2,4,5,7,8-hexa-
oxa-3-silonanes, h
yield of dihydro-
1,2,4,5,7,8-hexa-
oxa-3-silonane
peroxyperoxides
run
1, 2, and 5,b %
1
2
3
4
5
6
8a
8b
9a
9b
12a
12b
0.1
2.5
0.17
3.7
1.5
23
84
85
91
86
93 (9)c
94
SCHEME 3. Synthesis of 1,2,4,5-Tetraoxa-3-silinanes
a General reaction conditions for the hydrolysis: hexaoxasilonane (0.31
mmol) was dissolved in a solution (10 g) containing THF (9.78 g), H2O
(0.2 g), and H2SO4 (0.02 g), and the reaction mixture was kept at 6 °C
until the complete conversion of hexaoxasilonane was achieved (TLC
monitoring). b Yield based on the isolated product. c The hydrolysis time
was 0.1 h.
and 12a with nonsilylated analogss1,2,4,5,7,8-hexaoxonanes16s
shows that these peroxides behave similarly: they could be
stored without a noticeable decomposition for 2-3 months at
temperatures below 0 °C, at room temperature the decomposition
of 8a and 9a occurs noticeably for 1 month. The structures of
the resulting compounds were established by NMR spectroscopy
and elemental analysis. Since 1,2,4,5,7,8-hexaoxa-3-silonanes
have been previously unknown, it was important to obtain direct
evidence for the existence of these compounds by X-ray
diffraction. The X-ray diffraction study was carried out for
compounds 12a,b (Figure 1, X-ray data are included in the
Supporting Information).
of these compounds increases with increasing size of the alicycle
and the volume of the substituents at the silicon atom (Scheme
2, Table 3).
The differences in the hydrolysis rate of 1,2,4,5,7,8-hexaoxa-
3-silonanes in going from dimethylsilyl to diethylsilyl derivatives
are substantial, and the hydrolysis time increases by a factor of
ca. 15-25. An increase in the size of the alicycle has a smaller
effect on the hydrolytic stability of 1,2,4,5,7,8-hexaoxa-3-
silonanes.
In both molecules, the nine-membered rings adopt a twist-
boat-chair conformation (pseudo-C3 conformer); the average Si-
O, O-O, and C-O bond lengths are 1.666(4), 1.474(5), and
1.419(6) Å, respectively. The crystal structures are typical of
branched hydrocarbons, with hydrophobic space-filling contacts
reflecting the simple close-packing of hydrophobic molecules.17
Hydrolysis of Hexaoxasilonanes in an Acidic Medium. The
resulting 1,2,4,5,7,8-hexaoxa-3-silonanes are unstable in the
presence of acids and are decomposed by water. The hydrolysis
of hexaoxasilonanes was found to result in the virtually complete
transformation of these compounds into 1,1′-dihydroperoxyper-
oxides (84-94% yields). Hence, the dialkylsilyl fragment can
be considered as a convenient protecting group for 1,1′-
dihydroperoxyperoxides. According to the results of the hy-
drolysis of hexaoxasilonanes 8a,b, 9a,b, and 12a,b in THF
containing 2% of water and 0.2% of sulfuric acid, the stability
Synthesis of 1,2,4,5,3-Tetraoxa-3-silinanes. Based on the
knowledge of the ring strain, 1,2,4,5-tetraoxa-3-silinanes would
be expected to be produced selectively to form stable six-
membered rings. However, our expectations were not completely
fulfilled. The results of the reactions of dialkyldichlorosilanes
7a-c,f with 1,1-bishydroperoxides 14-16 (Scheme 3) differ
substantially from those with dihydroperoxyperoxides 1-5
(Scheme 1).
Under the conditions analogous to the synthesis of 8-13,
1,2,4,5-tetraoxa-3-silinanes 17-19 were isolated in the indi-
vidual state in none of the experiments. These compounds did
not withstand the purification on different (including silanized)
SiO2 and Al2O3. Attempts to separate tetraoxasilinanes from
amines led to the formation of silicon-containing oligomers. The
NMR monitoring of the reaction proceeding according to
FIGURE 1. Molecular structure of 12a,b, showing the atomic numbering and 40% probability displacement ellipsoids. H atoms omitted for
clarity.
J. Org. Chem, Vol. 73, No. 8, 2008 3173

Terent’ev et al.
by flash chromatography using a short silica gel column (hexane-
CH2Cl2, 20:1): yield 84% (0.166 g, 0.48 mmol); white crystals;
mp ) 44-45 °C; Rf 0.52 (TLC, hexane-EA, 20:1); 1H NMR (300
MHz, CDCl3) δ 0.77 (q, 4H, J ) 7.5 Hz), 1.04 (t, 6H, J ) 7.5
Hz), 1.34-1.99 (m, 20H); 13C NMR (75 MHz, CDCl3) δ 2.4, 6.4,
22.7, 25.6, 30.1, 30.2, 108.5. Anal. Calcd for C16H30O6Si: C, 55.46;
H, 8.73; Si, 8.11. Found: C, 55.64; H, 8.63; Si, 8.37.
Scheme 3 in CDCl3 in the presence of pyridine showed that
1,2,4,5-tetraoxa-3-silinanes 17-19 are formed as virtually the
only products, but they undergo decomposition (10-20 h).
Apparently, these compounds are stable over a period of time
in dilute solutions in the presence of amines, with which these
compounds form rather stable complexes.
Synthesis of Ethyl 4-(29-Methyl-13,14,27,28,30,31-hexaoxa-
29-siladispiro[11.2.11.5]hentriacont-29-yl)butanoate, 12g. 1,1′-
Dihydroperoxydi(cyclododecyl)peroxide 5 (0.2 g, 0.47 mmol) was
added to a solution of imidazole (0.095 g, 1.40 mmol) and ethyl
4-[dichloro(methyl)silyl]butanoate 7g (0.13 g, 0.57 mmol) in THF
(8 mL). The reaction mixture was stirred at 20-25 °C for 12 h
and then filtered. The residue was washed with THF (2 × 5 mL).
The majority (∼15 mL) of the filtrate was evaporated, and MeOH
(15 mL) was added. The residue of 12g was precipitated. The
suspension was cooled at -10 °C, and the residue of 12g was
filtered. Peroxide 12g was washed with MeOH (4 × 5 mL) and
dried under reduced pressure (10-20 Torr) at room temperature
for 2 h: yield 74% (0.203 g, 0.35 mmol); white crystals; mp )
97-99 °C; Rf 0.36 (TLC, hexane-EA, 20:1); 1H NMR (300 MHz,
CDCl3) δ 0.27 (s, 3H), 0.83 (t, 2H, J ) 6 Hz) 1.18-1.89 (m, 49H),
2.38 (t, 2H, J ) 7.3 Hz), 4.15 (q, 2H, J ) 7.3 Hz); 13C NMR (75
MHz, CDCl3) δ -6.6, 11.7, 14.3, 18.6, 19.2, 19.5, 21.9, 22.2, 25.9,
26.2, 26.4, 37.1, 60.1, 112.6, 173.5. Anal. Calcd for C31H58O8Si:
C, 63.44; H, 9.96; Si, 4.79. Found: C, 63.38; H, 9.62; Si, 4.80.
Hydrolysis of 15,15-Diethyl-6,7,13,14,16,17-hexaoxa-15-
siladispiro[4.2.4.5]heptadecane, 8b. Peroxide 8b (0.1 g, 0.31
mmol) was added to a solution of THF (9.78 g), H2O (0.2 g), and
H2SO4 (0.02 g) at 6 °C. The mixture was kept at this temperature
for 2.5 h (TLC monitoring) for a complete hydrolysis of 8b. K2-
CO3 (0.5 g) was added to the mixture, and the suspension was
stirred at room temperature for 0.5 h. The suspension was filtered,
and the filtrate was concentrated. 1,1′-Dihydroperoxydi(cyclopen-
tyl)peroxide 1 was isolated by silica gel column chromatography
(hexane-Et2O, 10:1): yield 85% (0.063 g, 0.27 mmol); white
Conclusion
A general procedure was developed for the synthesis of
1,2,4,5,7,8-hexaoxa-3-silonanes, new class of cyclic peroxides,
containing one Si atom and three O-O fragments in one ring.
The method is based on the reaction of 1,1′-dihydroperoxyper-
oxides with disubstituted dialkylsilanes in the presence of
aromatic nitrogen bases. The main reaction pathway involves
the formation of cyclic rather than oligomeric (linear) peroxides.
In contradiction to the common rule of the steric strain of the
carbocyclic structures, the nine-membered cyclic peroxides
1,2,4,5,7,8-hexaoxa-3-silonanes are much more stable than their
six-membered cyclic analogs 1,2,4,5-tetraoxa-3-silinanes, which
were isolated in the individual state in none of the experiments.
The formation of 1,2,4,5-tetraoxa-3-silinanes was detected by
NMR spectroscopy in the reaction of dialkyldichlorosilanes with
gem-bishydroperoxides.
Experimental
Caution: Although we have encountered no difficulties in
working with peroxides, precautions, such as the use of shields,
fume hoods, and the avoidance of transition-metal salts, heating,
and shaking, should be taken whenever possible. It should be
mentioned that although some 1,2,4,5,7,8-hexaoxonanes display
remarkable sensitivity towards friction or shock,17,18 similar
1,2,4,5,7,8-hexaoxa-3-silonanes are more stable under these
conditions.
1
crystals; mp ) 60-63 °C; H NMR (200.13 MHz) δ 1.55-1.82
(m, 8H), 1.83-2.11 (m, 8H), 9.80-10.05 (br s, 2H); 13C NMR
(50.32 MHz) δ 24.4, 33.2, 122.2.
Synthesis
of
17,17-Diethyl-7,8,15,16,18,19-hexaoxa-17-
siladispiro[5.2.5.5]nonadecane, 9b. 1,1′-Dihydroperoxydi(cyclo-
hexyl)peroxide 2 (0.15 g, 0.57 mmol) was added to a solution of
imidazole (0.12 g, 1.76 mmol) and dichlorodiethylsilane 7b (0.11
g, 0.70 mmol) in THF (6 mL). The reaction mixture was stirred at
20-25 °C for 3 h and then filtered. The residue was washed with
THF (2 × 5 mL). The filtrate was concentrated, and 9b was isolated
Acknowledgment. This work is supported by the Program
for Support of Leading Scientific Schools of the Russian
Federation (Grant No. NSh 5022.2006.3), the Grant of President
of Russian Federation (No. MK-3515.2007.3), and the Russian
Science Support Foundation.
Supporting Information Available: Experimental procedures
for the synthesis of 1,2,4,5,7,8,3-hexaoxasilonanes 8-13, 1,2,4,5,3-
tetraoxasilinanes 17-19, 1,1′-dihydroperoxyperoxides 1-6, and
(16) Terent’ev, A. O.; Platonov, M. M.; Sonneveld, E. J.; Peschar, R.;
Chernyshev, V. V.; Starikova, Z. A.; Nikishin, G. I. J. Org. Chem. 2007,
72, 7237-7243.
(17) Dubnikova, F.; Kosloff, R.; Almog, J.; Zeiri, Y.; Boese, R.; Itzhaky,
H.; Alt, A.; Keinan, E. J. Am. Chem. Soc. 2005, 127, 1146 -1159.
(18) (a) Meyer, R.; Ko¨hler, J.; Homburg, A. ExplosiVes, 5th ed.; John
Wiley-VCH: Weinheim, 2002. (b) Dubnikova, F.; Kosloff, R.; Zeiri, Y.;
Karpas, Z. J. Phys. Chem. A 2002, 106, 4951-4956.
1
gem-bishydroperoxides 14-16, H and 13C NMR spectra for all
peroxides, and details of X-ray data for 12a and 12b. This material
is available free of charge via the Internet at http://pubs.acs.org.
JO7027213
3174 J. Org. Chem., Vol. 73, No. 8, 2008