A new method for the synthesis of primary hydroperoxides. A useful application of bis(tributyltin) oxide in the hydrolysis of peroxyesters

Article abstract of DOI:10.1055/s-2001-13365

Hydrolysis of peroxyesters in the presence of bis(tributyltin) oxide provides a new method for the synthesis of hydroperoxides including methyl and ethyl hydroperoxide.

Full text of DOI:10.1055/s-2001-13365

LETTER
623
A New Method for the Synthesis of Primary Hydroperoxides. A Useful
Application of Bis(tributyltin) Oxide in the Hydrolysis of Peroxyesters
Stefan Baj,* Anna Chrobok
Institute of Organic Chemistry and Technology, Silesian University of Technology, ul. Krzywoustego 4, 44-100 Gliwice, Poland
E-mail: baj@polsl.gliwice.pl
Received 31 January 2001
Hydroxide ion can also attack the proton adjacent to the
peroxide bond in peroxyester molecule resulting in het-
erolytic fragmentation. It is known that peroxyesters are
very sensitive to bases and decompose to yield acids, ke-
tones or aldehydes.5 Particularly, n-alkyl peroxyesters are
very sensitive to hydroxide anions. This might be a reason
why this problem has not been explored, yet. Additional-
ly, it seems to be interesting to obtain primary alkyl hy-
droperoxides via the peroxyester hydrolysis pathway.
Moreover, only few primary hydroperoxides9 are avail-
able; their preparation is difficult and unsafe. Ethyl
hydroperoxide10 was synthesised by using the reaction of
diethyl sulphate with dilute hydrogen peroxide in the pres-
ence of aqueous potassium hydroxide. The reaction was
also used to prepare methyl and propyl
hydroperoxides10,11 and still seems to be the method of
choice for these compounds.5 Yields are low because of
the concomitant base-catalysed decomposition of the hy-
droperoxides.
Abstract: Hydrolysis of peroxyesters in the presence of bis(tribu-
tyltin) oxide provides a new method for the synthesis of hydroper-
oxides including methyl and ethyl hydroperoxide.
Key words: bis(tributyltin) oxide, hydrolysis, peroxyesters, hydro-
peroxides, organic peroxyacids
Organotin alkoxides have recently received much atten-
tion for their utility in organic synthesis.1,2 A tributyl
alkoxide will catalyse the transesterification between an
alcohol and an ester3 and sensitive esters can be hydroly-
sed under essentially neutral conditions with bis(tributyl-
tin) oxide.4 It would be interesting to investigate whether
the hydrolysis of peroxyesters in the presence of this com-
pound is possible.
There are only few studies about the hydrolysis of perox-
yester in the literature.5,6 It is known, that, when peroxyes-
ters are hydrolysed, the products formed are acids and
hydroperoxides.7 Hydroxide ion is able to attack the acyl
carbon, resulting in hydrolysis of the peroxyester via a tet-
rahedral intermediate.8 Only the hydrolysis of tert-alkyl
peroxyesters in the presence of concentrated base solution
has been described.
In conclusion, mild basic or neutral conditions have to be
used to hydrolyse n-alkyl peroxyesters. Here, we present
a new method for peroxyester hydrolysis under mild con-
ditions in the presence of bis(tributyltin) oxide.
Table Hydrolyses of Peroxyesters in the Presence of Bis(tributyltin) Oxide in Diethyl Ether
a yield of hydroperoxides was determined according to the known procedures by iodometric titration.15
Synlett 2001 No. 5, 623–624 ISSN 0936-5214 © Thieme Stuttgart · New York

624
S. Baj, A. Chrobok
LETTER
(7) Milas, N. A.; Surgenor, D. M. J. Am. Chem. Soc. 1946, 68,
642.
(8) Antonovskii, V. L.; Buzlanova, M. M.; Frolova, Z. S. Kinet.
Katal. 1967, 8, 671.
(9) (a) Dussault, P. H.; Sahli, A. J. Org. Chem. 1992, 57, 1009; (b)
Dussault, P. H.; Zope, U. R.; Westermeyer, T. A. J. Org.
Chem. 1994, 59, 8267.
(10) Rieche, A.; Bischoff, C. Ber. 1961, 94, 2722.
(11) Fisher, I. P.; Tipper, C. F. H. Trans. Faraday Soc. 1963, 59,
1174;
First, the method has been tested on cumyl peroxybu-
tyrate.12 This model tert-alkyl peroxyester and the result-
ing cumyl hydroperoxide are relatively stable substances.
A mixture of cumyl peroxybutyrate (0.7 g, 3.00 mmol)
and (n-Bu3Sn)3O (3.6 g, 6.00 mmol) in ether (50 ml) was
stirred at 25 °C in a thermostatic three-necked 100 cm3
flask, equipped with a mechanical stirrer. The progress of
the reaction was monitored by HPLC.13 No thermal de-
composition products of the peroxyester or hydroperoxide
were observed in the reaction mixture. At the end of the
reaction (30 h), 20 ml of H2O was added and the mixture
was saturated with CO2. The aqueous layer was extracted
with ether. The combined organic layers were dried over
MgSO4 and evaporated to dryness; the residue was chro-
matographed with hexane : 2-propanol (99:1) to remove
butyric acid, organotin compounds and to afford pure
cumyl hydroperoxide.
(12) (a) Baj, S.; Chrobok, A. Polish J. Chem. 1999, 73, 1185; (b)
1H NMR and 13C NMR were recorded at 300 MHz in CDCl3
(Varian Unity Inova plus, internal TMS); Cumyl
peroxybutyrate: 1H NMR: 0.82 (t, J = 7.2 Hz, 3H), 1.52
(sextet, J = 7.2 Hz, 2H), 1.66 (s, 6H), 2.11 (t, J = 7.2 Hz, 2H),
7.23-7.49 (m, 5H); 13C NMR: 13.0, 18.0, 26.5, 33.0, 85.9,
125.4, 127.5, 128.2, 144.2, 170.4.
(13) (a) Baj, S.; Chrobok, A. J. Liq. Chromatogr. 2000, 23, 551; (b)
HPLC was performed on liquid chromatograph (Alliance,
Waters 2690 system) with Waters photodiode array detector
and cartridge column (Nova-Pak Silica 4 m; 3.9 150 mm)
and precolumn module; solvent system included hexane/2-
propanol (99.5/0.5, 1 ml/min).
(14) (a) Baj, S.; Chrobok, A. J. Chem. Soc. Perkin 1. 2000, 2575;
(b) Methyl peroxybenzoate: 1H NMR: 4.14 (s, 1H), 7.41-
7.95 (m, 5H); 13C NMR: 64.7, 126.3, 127.7, 128.2, 133.3,
163.9; Ethyl peroxybenzoate: 1H NMR : 1.39 (t, J = 7.8 Hz,
3H), 4.41 (q, J = 7.4 Hz, 2H), 7.42-7.96 (m, 5H); 13C NMR:
12.9, 72.5, 127.2, 128.5, 129.3, 133.4, 164.2.
The same procedures were used for methyl and ethyl per-
oxybenzoate reactions. We have synthesised these novel
compounds by alkylation of organic peroxyacids under
phase transfer catalysis conditions, earlier.14 The hydroly-
sis reactions were carried out at 10 °C. Because the re-
sulting methyl and ethyl hydroperoxides are dangerously
unstable, especially after drying, the concentration of
these compounds was determined in solution by iodomet-
ric titration.15 The NMR studies were also made in solu-
tion.16
(15) (a) Kolthof, J. M.; Medalia, A. J. J. Am. Chem. Soc. 1949, 71,
22; (b) Zawadiak, J.; Gilner, D.; Kulicki, Z.; Baj, S. Analyst,
1993, 118, 1081; (c) Bartlett, P. D.; Hiatt, R. R. J. Am. Chem.
Soc. 1958, 80, 1398.
In summary, we have shown that it is possible to hydrol-
yse sensitive peroxyesters in the presence of bis(tributyl-
tin) oxide. In addition, we have elaborated a new method
for the synthesis of short alkyl chain hydroperoxides that
has not been available before. The reactivity of peroxyes-
ters in this reaction will be the subject of further studies in
our laboratory.
(16) Ethyl hydroperoxide. A mixture of ethyl peroxybenzoate
(0.25 g, 1.51 mmol) and (n-Bu3Sn)3O (1.79 g, 3.02 mmol) in
ether (40 ml) was stirred at –10 °C in a thermostatic three-
necked 100 cm3 flask, equipped with a mechanical stirrer. At
the end of the reaction (15 h lack of starting material on
HPLC), 10 ml of H2O was added and the mixture was
saturated with CO2. The aqueous layer was extracted with
ether. The combined organic layers were dried over MgSO4
and evaporated to about 2 ml (Caution: evaporating to dryness
is dangerous); the residue was chromatographed (hexane) to
remove benzoic acid, organotin compounds and to afford a
pure hexane solution of ethyl hydroperoxide. The yield of
hydroperoxides was determined by iodometric titration.
1H NMR and 13C NMR were recorded at 300 MHz in CDCl3
(Varian Unity Inova plus, internal TMS) in solution of ethyl
hydroperoxide in hexane (the proton of the -OOH group was
not observed because of high dilution of the hydroperoxides).
Methyl hydroperoxide: 1H NMR: 3.91 (s, 3H); 13C NMR:
63.4; Ethyl hydroperoxide: 1H NMR: 1.38 (t, J = 7.8 Hz,
3H), 4.35 (q, J = 7.4 Hz, 2H); 13C NMR: 12.9, 63.2.
Acknowledgement
The authors thank Prof. Alwyn G. Davies for his useful advice.
References and Notes
(1) Davis, A. G.; Kleinschmidt, D. C.; Palan, P. R.; Vasishtha, S.
C. J. Chem. Soc. C. 1971, 3972.
(2) Davies, A. G. J. Chem. Soc. Perkin 1. 2000, 1997.
(3) Steliou, K.; Szczygielska-Nowosielska, A.; Favre, A.;
Poupart, M. A.; Hanessian, S. J. Am. Chem. Soc. 1980, 102,
7578.
(4) Mata, E. G.; Mascaretti, O. A. Tetrahedron Lett. 1988, 29,
6893.
(5) Sawaki, Y. Organic Peroxides; Ando, W., Ed.; Wiley
Interscience: New York, 1992; p. 450.
Article Identifier:
1437-2096,E;2001,0,05,0623,0624,ftx,en;G02201ST.pdf
(6) Yurzhenko, T. I.; Nosan, V. N. Ukr. Khim. Zh. 1967, 1283.
Synlett 2001, No. 5, 623–624 ISSN 0936-5214 © Thieme Stuttgart · New York