Ozonolysis of verbenone in aprotic solvents

Article abstract of DOI:10.1016/j.mencom.2009.03.019

The ozonolysis of verbenone in methylene chloride and acetonitrile at -60 and 0 °C proceeds with cleavage of the double bond and neighbouring σ-bond to give (1R,3S)-acetyl-2,2-dimethylcyclobutane carboxylic acid. The mechanism of the reaction has been pro

Full text of DOI:10.1016/j.mencom.2009.03.019

Mendeleev
Communications
Mendeleev Commun., 2009, 19, 106–107
Ozonolysis of verbenone in aprotic solvents
a
a
b
b
Olga S. Kukovinets, Tatyana I. Zvereva,* Natalya N. Kabalnova, Vakhtang G. Kasradze,
b
b
a
b
Elena V. Salimova, Lyucia R. Khalitova, Marat I. Abdullin and Leonid V. Spirikhin
a
b
Department of Chemical Technology, Bashkirian State University, 450014 Ufa, Russian Federation.
Fax: +7 8347 228 6257; e-mail: salimovaev@mail.ru
Institute of Organic Chemistry, Ufa Scientific Center of the Russian Academy of Sciences, 450054 Ufa,
Russian Federation
DOI: 10.1016/j.mencom.2009.03.019
The ozonolysis of verbenone in methylene chloride and acetonitrile at –60 and 0 °C proceeds with cleavage of the double bond
and neighbouring σ-bond to give (1R,3S)-acetyl-2,2-dimethylcyclobutane carboxylic acid. The mechanism of the reaction has
been proposed.
The ozonolysis of olefins is widely used in synthetic organic
chemistry because it allows one to introduce oxygen-containing
substituents into a molecule for the synthesis of biologically
of keto groups at 196.68, 201.39 and 201.49 ppm. The first
signal corresponds to keto functions in peroxide 4b, the other,
to keto functions in dimer 4a. The aldehyde group neigbouring
1
13
active compounds. However, the results of the reaction of a
with a keto group appears at 188.71 ppm. In the C NMR
cycloolefin with ozone are not always identical, especially
when in the substrate there are functional groups which can
react with obtained peroxides leading to anomalous ozonolysis
products. For instance, the ozonolysis of α,β-unsaturated
carbonyl compounds occurs with the additional cleavage of a
neighbouring σ-bond to shorten a hydrocarbon chain.2 The
mechanism of enone ozonolysis depends on the structural environ-
ment of the reacting double bond and ozonolysis conditions.
This work is devoted to the study of the structure of peroxide
products of verbenone ozonolysis in aprotic solvents, the dynamics
of peroxide decomposition and the composition of the products
with the aim to reveal the possible reaction mechanisms.
spectrum, two carbon atoms of an acetal fragment are also
observed (98.42 ppm for 4a and 109.97 ppm for 4b).
1
In the H NMR spectrum of dimer peroxides 4a,b, the signals
of protons of the aldehyde groups are observed at 8.99 ppm, and
the proton at carbon atom bound with two oxygens – at 4.95 ppm.
,3
O
O
O
O
O
O3/CD2Cl2
1
CHOO
+
CHO
–
60 °C
3
a
3b
O
O
O
O
The ozonolysis of verbenone 1 in methylene chloride and
acetonitrile gives (1R,3S)-3-acetyl-2,2-dimethylcyclobutane
carboxylic acid 2 as the main product (Scheme 1).
O
O
O
O
i, O3/MeCN, –40 °C
O
4a
t
+
ii, –40 °C
20 °C
COOH
O
O
O
O
O
O
O
OHC
CHO
1
(1R,3S)-2 (83%)
Scheme 1
4
b
The reaction stoichiometry of verbenone 1 with ozone at dif-
Scheme 2
ferent temperatures (0, –40 and –60 °C) was determined according
4
to a published method. The data on the ozone quantity needed
Dimer peroxides 4a,b are unstable, that is testified by the
decrease of their concentration at heating the reaction mass to
room temperature.
After the ozonization, the concentration of dimers is practically
equal to the concentration of initial verbenone 1; at –40 °C,
it decreases by two times, and at room temperature they
decompose completely (Table 2).
for the total verbenone conversion are presented in Table 1.
The stabilization of resulting carbonyl oxides depends on
1
13
the reaction temperature. The H and C NMR spectra of the
products of the ozonolysis carried out in CD Cl at –60 °C
2
2
showed that the reaction results in the formation of carbonyl
oxides 3a,b, which are transformed into dimer peroxides 4a,b
(
Scheme 2), that is the meaning by the signals of carbon atoms
Table 2 Peroxide concentration dependence on ozonization conditions
–
3
Table 1 Ozone consumed depending on the ozonolysis conditions of
verbenone 1 (1 mmol).
(verbenone concentration is 0.22 mol dm ).
Peroxide concentration/mol dm–3
Consumed O3/
mmol
Entry
T/°C
Solvent
CH2Cl2
Entry
T/°C
Solvent
Yield of 2 (%)
Ozonolysis temperature
0.21
25 °C
0.05
1
2
3
–60
–40
0
CH Cl2
1.1–1.3
70
1
2
3
–60
–40
0
2
MeCN
1.1–1.3
1.1–1.3
83
71
MeCN
CH2Cl2
0.11
0.10
0.05
0.06
CH Cl2
2
MeCN
1.5–1.7
57
MeCN
0.06
0.06
©
2009 Mendeleev Communications. All rights reserved.
– 106 –

Mendeleev Commun., 2009, 19, 106–107
The increase in the temperature of compounds 4a,b leads to
O
O
O
O
the rearrangement into mixed anhydride 5, which, according
to spectral data, results from both peroxides. Probably, this
rearrangement of peroxide 4b occurs via dimer 6 (Scheme 3).
3
a,b
H +
CHO
–
O2, – CO2
O
O
O
O
7
8
O
O
O
O
O3/O2 MeCN
4
a,b
+
2
Scheme 4
O
References
O
O
O
O
O
O
1
2
3
O. S. Kukovinets, T. I. Zvereva, V. G. Kasradze, F. Z. Galin, L. L. Frolova,
A. V. Kuchin, L. V. Spirikhin and M. I. Abdullin, Khim. Prir. Soedin.,
O
O
+
O
H
O
–
60
20 °C
2
006, 42, 179 [Chem. Nat. Compd. (Engl. Transl.), 2006, 42, 216].
O
F. Z. Galin, O. S. Kukovinets, R. A. Zainullin, V. V. Shereshovets, Yu. A.
Kashina, A. M. Akhmetov, R. V. Kunakova and G. A. Tolstikov, Zh.
Org. Khim., 2001, 37, 251 (Russ. J. Org. Chem., 2001, 37, 238).
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G. Yu. Ishmuratov and G. A. Tolstikov, Zh. Org. Khim., 2002, 38, 1047
5
2
t
6
Scheme 3
(
Russ. J. Org. Chem., 2002, 38, 1005).
The intermediate formation of anhydride 5 is confirmed
by spectroscopic data. In the C NMR spectrum, the signal at
88.71 ppm disappears and the signals of carbon atoms of
the anhydride fragment appear (156.67 and 169.84 ppm). The
signal of the carbonyl atom of the acetyl fragment is observed at
4 V. V. Shereshovets, V. D. Komissarov and E. T. Denisov, Neftekhimiya,
1980, 20, 245 (in Russian).
1
3
5
6
O. A. Reutov, A. L. Kurts and K. P. Butin, Organicheskaya Khimiya,
BINOM, Moscow, 2004, vol. 3 (in Russian).
I. N. Komissarova, V. D. Komissarov and E. T. Denisov, Izv. Akad. Nauk
SSSR, Ser. Khim., 1978, 1991 (Bull. Acad. Sci. USSR, Div. Chem. Sci.,
1
2
06.51 ppm. On storage, compound 5 decomposes to acid 2.
1
978, 27, 1751).
According to the results, the formation of dimer peroxides
proceeds only at reduced temperatures. The ozonolysis in aprotic
solvents at –20 °C occurs, probably, otherwise. The aldehyde
groups of compounds 7 and 8 resulted from zwitterions of 3a,b
are oxidized by ozone with the formation of the single product –
ketoacid 2 (Scheme 4). The possibility of such a transformation
5
is described in the literature. The reaction in aprotic solvents at
–
1
20 °C leads to the consumption of 1.5–1.7 mol of ozone per
mol of verbenone, that is conformed to the mechanism of
6
aldehydes oxidation by ozone.
Received: 25th July 2008; Com. 08/3190
–
107 –