Electrosynthesis of esters of mono- and dioxoalkanoic and alkanedioic acids on the basis of nitro-substituted alkyl carboxylates and cycloalkanones

Article abstract of DOI:10.1023/A:1023935629115

A one-pot electrochemical method for the synthesis of methyl monooxoalkanoates with the carbonyl group in position 4, methyl dioxoalkanoates with the oxo groups in positions 4,7-, 6,9-, 7,10-, and 12,15, and methyl 4-oxoalkanedioates was developed. This method is based on amperostatic electrolysis in an undivided cell of the salts of esters of nitroalkanoic acids and their adducts with CH₂=CHX (X = Ac, CO₂Me).

Full text of DOI:10.1023/A:1023935629115

728
Russian Chemical Bulletin, International Edition, Vol. 52, No. 3, pp. 728—733, March, 2003
Electrosynthesis of esters of monoꢀ and dioxoalkanoic and
alkanedioic acids on the basis of nitroꢀsubstituted
alkyl carboxylates and cycloalkanones*
ꢀ
Yu. N. Ogibin, A. I. Ilovaiskii, V. M. Merkulova, and G. I. Nikishin
N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5328. Еꢀmail: ogibin@ioc.ac.ru
A oneꢀpot electrochemical method for the synthesis of methyl monooxoalkanoates with
the carbonyl group in position 4, methyl dioxoalkanoates with the oxo groups in positions
4,7ꢀ, 6,9ꢀ, 7,10ꢀ, and 12,15, and methyl 4ꢀoxoalkanedioates was developed. This method is
based on amperostatic electrolysis in an undivided cell of the salts of esters of nitroalkanоic
acids and their adducts with СН2=СНХ (Х = Aс, СО2Ме).
Key words: methyl 4ꢀoxoalkanоates, dimethyl 4ꢀoxoalkanedioates, methyl 4,7ꢀ, 6,9ꢀ, 7,10ꢀ,
and 12,15ꢀdioxoalkanоates, electrolysis, salts of nitro compounds, methyl 4ꢀnitroalkanоates,
2ꢀnitrocycloalkanones.
Previously, we found1 that salts of nitro compounds
with an increase in the chain length. For this reason and
(SNC) in methanol can be efficiently transformed with
high selectivity into carbonyl compounds by amperostatic
electrolysis in an undivided cell. As a development of this
study, this work deals with electrochemical transformaꢀ
tions of SNC 1—4, containing acyl and methoxycarbonyl
groups (Schemes 1 and 2). The goal was to develop a new
route to esters of monoꢀ and dioxoalkanоic and monoꢀ
oxoalkanedioic acids, which are versatile blocks for the
construction of heterocyclic systems, cyclopentanoid
structures and pheromones.2
also due to oligomerization of MVK under given condiꢀ
tions, salt 3e cannot be obtained in this way. This salt was
synthesized by the reaction of 2ꢀnitrocyclododecanone
(6е) with MVK in a THF solution in the presence of a
catalytic amount of Ph3P 2 followed by treatment of adꢀ
duct 7 with a methanolic solution of MeONa.
Scheme 2
The starting salts 1 were prepared by the reaction
of methyl 4ꢀnitroalkanoates 1´a,b with 1 equiv. of
МеОNa, and salts 2, 3, and 4 were synthesized from
methyl 4ꢀnitrobutanoate (5) and 2ꢀnitrocycloalkanоnes
6b—e (Schemes 1 and 2).
Scheme 1
R = Me (a), Et (b)
The rate of addition of salts 2 to methyl vinyl ketone
(MVK) and methyl acrylate (МА) markedly decreases
n = 2 (a), 4 (b), 5 (c), 6 (d), 10 (e)
* Dedicated to Academician I. P. Beletskaya on the occasion of
her anniversary.
Reagents and conditions: а. MeOH, MeONa (1 equiv.); b. MVK
or MA (1.5 equiv.); c. MVK (1.5 equiv.), THF, Ph3P.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 697—702, March, 2003.
1066ꢀ5285/03/5203ꢀ728 $25.00 © 2003 Plenum Publishing Corporation

Electrosynthesis of oxoalkanoates
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
729
Table 1. Preparation of salts 1 and 2 from methyl 4ꢀnitroalkanоates 1´ and 5 and 2ꢀnitrocycloꢀ
alkanones 6 and electrolysis of the saltsa
Nitro
Salt preparation
Electrolysis
compound
Т/°С
τ/h
Salt
Anode
material
Salt conꢀ
version (%)
Product
Yieldb
(%)
1´a
1´b
1´b
1´b
5
6b
6с
6е
20
20
20
20
20
60
60
60
0.5
0.5
0.5
0.5
0.5
2
1a
1b
1b
1b
2a
2b
2c
2ed
Pt
Pt
G
GC
Pt
Pt
Pt
Pt
85
87
68
8a
8b
8b
65
76
58
75
15c
60
49
40
85
8b
100
100
100
90
11а
11b
11c
11е
2
3
a Conditions for salt preparation: nitro compound (2 mmol), МеONa (1 equiv.) in МеOH (50 mL).
Electrolysis conditions: amperostatic mode, anode current density 100 mA cm–2, quantity of
electricity 2 F mol–1, 10—15 °C; a platinum (Pt), graphite (G) or glassy carbon (GC) anode and a
stainlessꢀsteel cathode.
b Based on the starting nitro compound according to GLC analysis (for products 8) or isolated
yields (for products 11).
c Methyl 4ꢀoxobutanoate (12) is also formed, yield 5%.
d Degree of conversion of salt 6e into salt 2е is 80%.
Electrolysis of salts 1—4 as 0.1 M solutions in MeOH
was carried out at 10—15 °С in an undivided cell with a
platinum anode and a steel cathode. The electrolysis was
performed in an amperostatic mode at an anodic current
density of 100 mA cm–1 by passing 2 F of electricity per
mole of the substrate. In this process, salts 1—4 act simulꢀ
taneously as reactants and supporting electrolytes. In comꢀ
bination with generation of МеОNa during the electrolyꢀ
sis, this eliminates the necessity of using other electrolytes
and allows one to reach almost complete conversion of
salts 1—4 even when only the theoretical amount of elecꢀ
tricity has been passed (2 F mol–1). The degree of converꢀ
sion of salts 1 and 2 and the product yields diminish when
platinum is replaced by graphite (Table 1).
Analysis of the electrolysis products after treatment of
electrolyzates with dilute НСl shows (Scheme 3, Tables 1
Table 2. Preparation of salts 2—4 and their electrolysisa
Starting
compounds
Step a
τ/h
Step b
τ/h
Electrolysis
Т/°С
Salt
Т/°С
Salt
Anode
material
Prodꢀ
uct
Yieldb
(%)
5, MVK
5, MA
5, MA
20
20
20
60
60
60
60
60
60
60
20
60
0.5
0.5
0.5
2
2
2
2
2
2
2
2a
2a
2a
2b
2b
2b
2c
2c
2d
2d
7c
20
60
60
60
60
60
60
60
60
60
20
60
12
3
3
2
2
3a
4a
4a
3b
4b
4b
3c
4c
3d
4d
3e
4e
Pt
Pt
GC
Pt
GC
Pt
Pt
Pt
Pt
Pt
9a
60
77
75
68
70
70
50
67
78
53
37
48d
10a
10а
9b
10b
10b
9c
10c
9d
10d
9e
6b, MVK
6b, МА
6b, МА
6c, MVK
6c, МА
6d, MVK
6d, МА
6e, MVK
6e, МА
2
3.5
3.5
3.5
4
5
5
48
3.5
Pt
Pt
2e
10e
a Step a: МеONa (1 equiv.) in МеOH (50 mL); step b: MVK or МА (1.5 equiv.); electrolysis conditions are given in
note а to Table 1.
b Isolated yield based on the initial nitro compound.
c The reaction of 2ꢀnitrocyclododecane (6e) with MVK in THF in the presence of 0.1 equiv. of Ph3P (step c,
Scheme 2) gave adduct 7, which was converted into salt 3e under conditions of step a.
d The degree of conversion of 6e was 85%.

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Ogibin et al.
and 2) that salts 1a,b have been converted into monoꢀ
oxoalkanoates 8a,b with a 68—87% degree of conversion
and a 77—90% selectivity. Salts 3a—e are transformed
into dioxoalkanoates 9a—e, and salts 4a—e give rise
to monooxoalkanedioates 10a—e; the selectivities are
37—68% and 48—77%, respectively, based on the starting
nitro compound.
As indicated by the obtained results (low yield of the
aldehyde, the formation of side and unidentified resinous
products), the transformation of salts 2 into esters 11 and
aldehyde 12 is largely complicated by competitive particiꢀ
pation of these salts in side reactions. One of these is
addition of the salts of primary nitro compounds to formꢀ
aldehyde formed from МеОН as a side product (Henry
reaction). The major identified product obtained in
the electrolysis of the salt of 1ꢀnitrohexane, namely,
2ꢀnitroheptanꢀ1ꢀol, have resulted from this reaction. In
the case of salt 2a, electrogenerated radicals 13 are apparꢀ
ently involved into an intramolecular radical cyclization
(Scheme 5), similar to the reaction observed previously
during the freeꢀradical addition of dimethyl glutarate
to 1ꢀalkenes3 and in the freeꢀradical cyclization of
3ꢀcarboxyꢀ and 2ꢀalkoxycarbonylpropyl radicals.4
Scheme 3
Scheme 5
When considering the mechanism of electrochemical
transformation of SNC into carbonyl compounds,1 we
initially suggested that it includes crossꢀdimerization of
radicals 15, electrogenerated from SNC of type 14, to
give nitronic esters 16 and the subsequent transformation
of esters 16 into carbonyl compounds during the elecꢀ
trolysis and workup of the electrolyzate (Scheme 6).
Under similar conditions, salts 2a—c and 2e are transꢀ
formed into esters 11а—с and 11е (Scheme 4), which
were formed in 15, 60, 49, and 40% yields, respectively
(see Table 1); in addition, the reaction gives unidentified
resinous products, which remain at the origin during TLC
analysis of the electrolyzates (elution with petroleum
ether—AcOEt, 100 : 0 to 4 : 1). Apart from the aboveꢀ
mentioned products, electrolysis of salts 2a gives methyl
4ꢀoxobutanoate (12) in ∼5% yield.
Scheme 6
Scheme 4
While proposing this mechanism relying on indirect
experimental data reported in a previous study,1 we overꢀ
looked that electrolysis of SNC in МеОН may be accomꢀ
panied by electrooxidative coupling of these salts with
n = 2 (a), 4 (b), 5 (c), 10 (e)

Electrosynthesis of oxoalkanoates
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
731
methoxyl radicals and anions, i.e., by a process similar to
that taking place during the known oxidative coupling of
these salts with free radicals5 and nitrite, cyanide, arylꢀ
sulfonate, and azide anions.6—9 According to the studies
cited, this process consists of two steps: coupling of the
free radical generated by singleꢀelectron oxidation of the
SNC or the anion with either the anion or the SNC and
the subsequent oxidation of the resulting radical anions.
These data suggest, by analogy, an alternative mechanism
for the electrochemical transformation of SNC into carꢀ
bonyl compounds. As the key intermediate steps, this
mechanism may include coupling of methoxyl and
nitronate anions 14 with electrogenerated methoxyl and
nitronate radicals 15 (Scheme 7, pathways а and b) and
subsequent electrooxidation of the resulting radical anꢀ
ions 17 to give αꢀmethoxynitroalkanes 18. The transforꢀ
mation of these products into ketals 19 is apparently due
to nucleophilic substitution of a methoxy group for the
nitro group on treatment with sodium methoxide formed
in the electrolysis.
anode, i.e., by electrolysis conditions favorable for the
electrogeneration of methoxyl radicals from МеОН.
Generally, the main outcome of this study is the deꢀ
velopment of an original electrochemical method for the
synthesis of alkyl oxoꢀ and dioxocarboxylates from readily
available nitroꢀsubstituted alkyl carboxylates and cycloꢀ
alkanоnes. An important advantage of this method over
the traditional routes for the synthesis of these compounds
based on the use of inorganic or organic oxidants is that
these reagents are now replaced by electric current and
thus the environmental pollution is reduced.
Experimental
NMR spectra were recorded on Bruker АCꢀ200, Bruker
WMꢀ250, and Bruker AMꢀ300 spectrometers using CDCl3 as
the solvent. IR spectra were measured on a Specordꢀ80 specꢀ
trometer in thin films and in CCl4 solutions. Laboratory power
sources B5ꢀ44 and B5ꢀ50 with output current stabilization were
used to generate the direct current. The quantity of electricity
passed was measured using an electronic coulometer with a
digital display and with a current measurement limit of 20 А
(manufactured at the design department, Institute of Organic
Chemistry, Russian Academy of Sciences). GLC analysis was
carried out using a Varianꢀ3700 chromatograph (flame ionizaꢀ
tion detector, glass columns, 5% Carbowax 20M on Inerton and
5% XEꢀ60 on Chromaton NꢀAW). TLC analysis was carried out
using Silufol UVꢀ254 plates. Flash chromatography was carried
out on silica gel L 40/100 µm. Methanol was dehydrated by
distillation over magnesium methoxide. Methyl vinyl ketone,
methyl acrylate, nitrohexane, and nitrocyclohexane were comꢀ
mercial preparations (Aldrich).
Scheme 7
The initial methyl 4ꢀnitroalkanoates 1´a,b and 5 were preꢀ
pared by the reaction of the corresponding primary nitroalkanes
with methyl acrylate,10—12 and 2ꢀnitrocycloalkanones 6b—e were
synthesized by a known procedure13,14 from appropriate cycloꢀ
alkanones.
2ꢀNitrocyclohexanone (6b).13 M.p. 43 °C (hexane). 1H NMR,
δ: 1.65—1.90 (m, 2 H); 1.90—2.22 (m, 2 H); 2.30—2.72 (m, 4 H);
5.24 (dd, 1 H, J = 12.5 Hz, J = 6.5 Hz).
This alternative mechanism for the electrochemical
transformation of SNC into carbonyl compounds is in
much better agreement with the experimental results obꢀ
tained for the electrolysis of SNC in МеОН both previꢀ
ously1 and in this work than the mechanism proposed
earlier (see Scheme 6). In particular, it provides a more
substantiated explanation for the fact that the electrolysis
of SNC performed under the given conditions virtually
does not yield vicꢀdinitroalkanes, the products of oxidaꢀ
tive dimerization of SNC. Indeed, according to this
mechanism, the transformation of SNC into carbonyl
compounds along pathway а does not involve the nitronate
radicals responsible for the formation of vicꢀdinitroꢀ
alkanes; judging by the results of this work, this route is
almost the only or, at least, the major one. An important
argument supporting this assumption is the fact that the
transformation of SNC into ketals 19 is promoted by high
anodic current densities and the use of platinum as the
2ꢀNitrocycloheptanone (6c).13 M.p. 41—42 °C (hexane).
1H NMR, δ: 1.39—1.56 (m, 1 H); 1.56—1.81 (m, 2 H);
1.81—2.10 (m, 3 H); 2.10—2.51 (m, 2 H); 2.51—2.87 (m, 2 H);
5.42 (dd, 1 H, J = 7.5 Hz, 2.5 Hz).
2ꢀNitrocycloheptanone (6d).13 B.p. 62—65 °C (0.1 Torr);
20
1
nD 1.5040. H NMR, δ: 1.00—3.00 (m, 12 H); 5.40 (dd, 1 H,
J = 6.0 Hz).
2ꢀNitrocyclododecanone (6e).13 M.p. 78 °C (hexane).
1H NMR, δ: 1.20—1.45 (m, 14 H); 1.71 (m, 1 H); 1.86 (m, 1 H);
2.13 (m, 1 H); 2.37 (m, 1 H); 2.70 (m, 2 H); 5.16 (dd, 1 H, J =
10.5 Hz, J = 4.5 Hz). 13C NMR, δ: 20.87, 21.52, 22.45, 23.22,
23.47, 23.89, 25.54, 25.76, 27.88 (CH2); 36.16 (CH2CO);
92.08 (C); 199.92 (CO).
Synthesis of 4ꢀoxoalkanоates (8a,b) and alkanedioates
(11а—c,е) (general procedure) (see Table 1). Methyl nitroꢀ
alkanoate 1´ or 5 or 2ꢀnitrocycloalkanone 6 (2 mmol) was mixed
with 20 mL of a methanolic solution of MeONa (1 equiv.) and
the mixture was stirred until the nitro compound was comꢀ
pletely converted into its salt (0.5—3 h at 20—60 °C). Electrolyꢀ

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Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
Ogibin et al.
sis was carried out with intense stirring in an undivided cell
maintained at a constant temperature and equipped with a platiꢀ
num, graphite, or glassy carbon anode (3 cm2) and a stainlessꢀ
steel cathode (3 cm2) separated by a 3—5 mm distance. The
electrolysis was performed under amperostatic conditions, with
an anodic current density of 100 mA cm–2; the quantity of
electricity was 2 F mol–1 and the temperature was 10—15 °C.
After completion of the electrolysis, the reaction mixture with
diluted with water (40 mL), acidified with glacial АсOH (1 mL)
to transform the unreacted part of the aciꢀform salt into the
initial nitro compound, and extracted with CHCl3 (2×20 mL).
An aliquot portion was taken from the combined extracts, dried
with K2CO3, and analyzed by GLC using an internal standard
(dodecane, hexadecane) to estimate the degree of conversion of
the starting compound. To hydrolyze the resulting ketals, the
rest of the combined extracts was stirred with 2 М HCl (10 mL)
for 0.5 h, neutralized with a 5% solution of NaHCO3 (10 mL),
dried with K2CO3, and concentrated using a rotary evaporator.
The individual products were isolated by flash chromatography
of the residue using 100 : 0 to 90 : 10 petroleum ether—AcOEt
mixtures as eluents.
(30 min). Methyl vinyl ketone or МА (1.5 equiv.) was added and
the reaction mixture was stirred for 12 h at 20 °C in the case of
MVK or for 3 h at 60 °C in the case of МА until complete
conversion of salt 2а (GLC monitoring). Electrolysis was carꢀ
ried out according to the general procedure.
Methyl 4,7ꢀdioxooctanoate (9а).18 1H NMR, δ: 2.16 (s, 3 H,
Ме); 2.58 (t, 2 H, J = 7 Hz); 2.71 (s, 4 H); 2.78 (t, 2 H, J =
7 Hz); 3.66 (s, 3 H, OМе). 13C NMR, δ: 27.74, 36.03, 36.94 and
37.08 (CH2); 29.86 (Ме); 51.78 (OМе); 173.15 (COO); 207.03
and 207.39 (CO).
Dimethyl 4ꢀoxoheptaneꢀ1,7ꢀdiоate (10a).12,19 IR, ν/cm–1
:
1740, 1710. 1H NMR, δ: 2.58 (t, 4 H, J = 7 Hz); 2.76 (t, 4 H, J =
7 Hz); 3.64 (s, 6 H, OМе).
Synthesis of methyl dioxoalkanoates (9b—d) and monooxoꢀ
alkanediоates (10b—е) (see Table 2). 2ꢀNitrocycloalkanone
6b—е (2 mmol) was mixed with 20 mL of a methanolic solution
of MeONa (1 equiv.), the mixture was stirred at 60 °C up to
complete transformation of the substrate into sodium salt 2 (2 h),
MVK or МА (1.5 equiv.) was added, and the mixture was stirred
up to complete conversion of salt 2 (2—5 h, GLC monitoring).
The electrolysis and electrolyzate workup were carried out acꢀ
cording to the general procedure. The individual products were
isolated by flash chromatography (gradient elution in the hexꢀ
ane—AcOEt system, 100 : 0 to 4 : 1).
Methyl 6,9ꢀdioxodecanoate (9b).2 IR, ν/cm–1: 1730, 1708.
1H NMR, δ: 1.62 (m, 4 H); 2.18 (s, 3 H, Ме); 2.32 (m, 2 H);
2.47 (m, 2 H); 2.68 (m, 4 H); 3.66 (s, 3 H, МеO). 13C NMR, δ:
23.25, 24.47, 33.86, 36.12, 36.98 and 42.35 (CH2); 29.91 (Ме);
51.52 (МеO); 173.85 (COO); 207.13 and 208.93 (CO).
Methyl 7,10ꢀdioxoundecanoate (9c).2 1H NMR, δ: 1.29 (m,
2 H); 1.58 (m, 4 H); 2.14 (s, 3 H, Ме); 2.26 (t, 2 H, J = 7.5 Hz);
2.42 (t, 2 H, J = 7.5 Hz); 2.65 (m, 4 H); 3.62 (s, 3 H, OМе).
13C NMR, δ: 23.35, 24.67, 28.60, 33.82, 36.05, 36.89 and 42.44
(CH2); 29.90 (Ме); 51.43 (OМе); 173.96 (COO); 207.09 and
209.15 (CO).
Methyl 4ꢀoxopentanoate (8a).11 B.p. 65—66 °C (0.3 Torr).
IR, ν/cm–1: 1718, 1735. 1H NMR, δ: 2.18 (s, 3 H); 2.57 (t, 2 H,
J = 7 Hz); 2.73 (t, 2 H, J = 7 Hz); 3.66 (s, 3 H, OМе).
Methyl 4ꢀoxohexanoate (8b).15 1H NMR, δ: 1.01 (t, 3 H, J =
7.2 Hz); 2.42 (q, 2 H, J = 7.2 Hz); 2.52 (t, 4 H, J = 6.5 Hz); 2.68
(t, 4 H, J = 6.5 Hz); 3.62 (s, 3 H, OМе). 13C NMR, δ: 7.72
(Ме); 27.77, 35.83 and 36.58 (CH2); 51.64 (OМе); 173.17
(COO); 209.20 (CO).
Dimethyl succinate (11а).16 1H NMR, δ: 2.64 (s, 4 H); 3.71
(s, 6 H, OМе).
Dimethyl аdipate (11b).16 1H NMR, δ: 1.65 (m, 4 H); 2.32
(m, 4 H); 3.63 (s, 6 H).
Dimethyl pimelate (11c).16 1H NMR, δ: 1.40 (m, 2 H); 1.68
(m, 4 H); 2.38 (m, 4 H); 3.68 (s, 6 H).
Dimethyl dodecaneꢀ1,12ꢀdioate (11е).16 1H NMR, δ: 1.28
(s, 12 H); 1.52 (m, 4 H); 2.30 (t, 4 H, J = 7.1 Hz); 3.68 (s, 6 H).
13C NMR, δ: 25.04, 29.22, 29.28, 29.43, 34.19 (CH2); 51.47
(OМе); 174.35 (COO).
Electrooxidation of Na salt of 1ꢀnitrohexane. 1ꢀNitrohexane
(0.262 g, 2 mmol) was mixed with 20 mL of a methanolic soluꢀ
tion of MeONa (1 equiv.) and the mixture was stirred for 0.5 h at
20 °C. Electrolysis and the workup of the electrolyzate were
carried out according to the above general procedure. Flash
chromatography (gradient elution in 100 : 0 to 1 : 1 hexꢀ
ane—AcOEt systems) afforded 2ꢀnitroheptanol (yield 30%),
methyl hexanoate (10%), hexanal (5%), and 5,6ꢀdinitrodoꢀ
decane (3%).
2ꢀNitroheptanꢀ1ꢀol.17 1H NMR, δ: 0.90 (t, 3 H); 1.33
(m, 8 H); 1.70—2.00 (m, 2 H); 3.35 (br.s, 1 H, OH); 3.90 (dd,
1 H, J = 12.4 Hz, J = 2.8 Hz); 4.04 (dd, 1 H, J = 12.4 Hz, J =
8.0 Hz); 4.59 (m, 1 H, CH). 13C NMR, δ: 13.99 (C(7)); 22.38
(C(6)); 25.42 (C(4)); 29.94, 31.22 (C(3), C(5)); 63.32 (C(1));
89.56 (C(2)).
Methyl hexanoate.16 1H NMR, δ: 0.89 (t, 3 H); 1.28 (m, 4 H);
1.53 (m, 2 H); 2.32 (t, 2 H, J = 7 Hz); 3.68 (s, 3 H).
Synthesis of methyl 4,7ꢀdioxooctanoate (9a) and methyl
4ꢀoxoheptaneꢀ1,7ꢀdioate (10а) (see Table 2). Methyl 4ꢀnitroꢀ
butanoate (5) (2 mmol) was mixed with 20 mL of a methanolic
solution of MeONa (1 equiv.), and the mixture was stirred at
∼20 °C until the substrate was completely converted into salt 2а
Methyl 8,11ꢀdioxododecanoate (9d).2 1H NMR, δ: 1.27
(m, 4 H); 1.55 (m, 4 H); 2.14 (s, 3 H, Ме); 2.25 (t, 2 H, J =
6 Hz); 2.40 (t, 2 H, J = 6 Hz); 2.64 (m, 4 H); 3.61 (s, 3 H,
OМе). 13C NMR, δ: 23.53, 24.70, 28.72, 28.83, 33.93, 36.02,
36.86 and 42.60 (CH2); 29.91 (Ме); 51.42 (OМе); 174.10
(COO); 207.23 and 209.40 (CO).
Methyl 6ꢀoxononaneꢀ1,9ꢀdioate (10b).2 IR, ν/cm–1: 1732,
1710. 1H NMR, δ: 1.58 (m, 4 H); 2.27 (m, 2 H); 2.43 (m, 2 H);
2.49—2.72 (m, 4 H); 3.61 and 3.62 (both s, 6 H, МеO).
13C NMR, δ: 23.14, 24.39, 27.70, 33.76, 37.01 and 42.24 (CH2);
51.47 and 51.73 (OМе); 173.15 and 173.70 (COO); 208.33 (CO).
Dimethyl 7ꢀoxodecaneꢀ1,10ꢀdioate (10с).2 1H NMR, δ: 1.30
(m, 2 H); 1.60 (m, 4 H); 2.29 (t, 2 H, J = 7 Hz); 2.43 (t, 2 H, J =
7 Hz); 2.56 (t, 2 H, J = 6 Hz); 2.69 (t, 2 H, J = 6 Hz); 3.64 and
3.66 (both s, 6 H, OМе). 13C NMR, δ: 23.18, 24.52, 27.60,
28.48, 33.68, 36.91 and 42.28 (CH2); 51.28 and 51.56 (OМе);
173.07 and 173.85 (COO); 208.51 (CO).
Dimethyl 8ꢀoxoundecaneꢀ1,11ꢀdioate (10d).2 IR, ν/cm–1
:
1
1740, 1725. H NMR, δ: 1.28 (m, 4 H); 1.56 (m, 4 H); 2.26 (t,
2 H, J = 6 Hz); 2.40 (t, 2 H, J = 6 Hz); 2.53 (t, 2 H, J = 6 Hz);
2.67 (t, 2 H, J = 6 Hz); 3.62 and 3.63 (both s, 6 H, МеO).
13C NMR, δ: 23.47, 24.67, 27.65, 28.71, 28.79, 33.90, 36.95 and
42.54 (CH2); 51.39 and 51.70 (OМе); 173.20 and 174.06 (COO);
208.85 (CO).
Dimethyl 12ꢀoxopentadecaneꢀ1,15ꢀdiоate (10е).2 M.p. 57 °C
(hexane). 1H NMR, δ: 1.25 (s, 12 H); 1.59 (m, 4 H); 2.28 (t,

Electrosynthesis of oxoalkanoates
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 3, March, 2003
733
2 H, J = 6 Hz); 2.43 (t, 2 H, J = 6 Hz); 2.56 (t, 2 H, J = 6 Hz);
2.70 (t, 2 H, J = 6 Hz); 3.65 and 3.66 (both s, 6 H, OМе).
13C NMR, δ: 23.78, 24.93, 27.74, 29.08—29.33, 34.08, 37.00
and 42.78 (CH2); 51.34 and 51.67 (OМе); 173.20 and 174.20
(COO); 208.93 (CO).
3. Yu. N. Ogibin, N. G. Maksimova, G. E. Kondrashina, and
G. I. Nikishin, Zh. Org. Khim., 1970, 6, 1390 [J. Org. Chem.
(USSR), 1970, 6 (Engl. Transl.)].
4. Yu. N. Ogibin, E. I. Troyanskii, and G. I. Nikishin, Izv.
Akad. Nauk SSSR, Ser. Khim., 1974, 2239 [Bull. Acad. Sci.
USSR, Div. Chem. Sci., 1974, 23 (Engl. Transl.)].
5. B. C. Gilbert and R. O. C. Norman, Can. J. Chem., 1982,
60, 1379.
6. R. B. Kaplan and H. Schechter, J. Am. Chem. Soc., 1961,
83, 3535.
7. Z. Matacz, H. Piotrowska, and T. Urbanski, Pol. J. Chem.,
1979, 53, 187.
8. N. Kornblum, H. K. Singh, and W. J. Kelly, J. Org. Chem.,
1983, 48, 332.
9. I. V. Tselinskii, S. F. Mel´nikova, and S. A. Fedotov, Izv.
Akad. Nauk, Ser. Khim., 2002, 1354 [Russ. Chem. Bull., Int.
Ed., 2002, 51, 1466].
10. P. A. Bartlett, F. R. Green III, and T. R. Webb, Tetrahedron
Lett., 1977, 331.
11. D. W. Chasar, Synthesis, 1982, 841.
Methyl 12,15ꢀdioxohexadecanoate (9е).2 A solution of
2ꢀnitrocyclododecanone (6е) (2 mmol), MVK (3 mmol), and
Ph3P (0.1 mmol) in THF (10 mL) was stirred at 20 °C until 6е
was completely converted (48 h, GLC monitoring). A solution
was concentrated to dryness and the residue was recrystallized
from МеOH to give 2ꢀnitroꢀ2ꢀ(3ꢀoxobutyl)cyclododecanone (7),
yield 80%, m.p. 138—140 °C. 1H NMR, δ: 0.93—1.50 (m, 16 H);
2.05—2.50 (m, 7 H); 2.14 (s, 3 H); 2.75—2.87 (m, 1 H).
13C NMR, δ: 19.13, 21.36, 21.80, 21.94, 22.58, 23.28, 26.21,
26.38, 26.91, 30.51, 32.68 and 37.31 (CH2); 29.95 (Ме); 100.15
(C(12)); 200.82 and 205.86 (CO). The transformation of
nitroketone 7 into salt 3е, its electrolysis, and electrolyzate
workup were carried out by the general procedure. Ester 9е was
isolated by flash chromatography (gradient elution in a hexꢀ
ane—AcOEt system, 100 : 0 to 8 : 1). IR, ν/cm–1: 1730, 1700.
1H NMR, δ: 1.28 (s, 12 H); 1.65 (m, 4 H); 2.14 (s, 3 H, Ме);
2.25 (t, 2 H, J = 6 Hz); 2.42 (t, 2 H, J = 6 Hz); 2.62 (m, 4 H);
3.62 (s, 3 H, OМе). 13C NMR, δ: 23.63, 24.72, 28.70,
28.87—29.40, 33.93, 36.02, 37.13 and 42.60 (CH2); 29.93 (Ме);
51.41 (OМе); 174.10 (COO); 207.13 and 209.53 (CO).
12. R. Ballini, M. Petrini, and G. Rosini, Synthesis, 1987, 711.
13. R. H. Fischer, Synthesis, 1980, 261.
14. R. H. Fischer and H. M. Weinz, Lieb. Ann., 1979, 612.
15. T. Miyakoshi, Yukagaku, 1988, 37, 19; Chem. Abstrs., 1988,
109, 92232.
16. H. A. Szymanski and R. E. Yelin, NMR Band Handbook,
IFI/Plenum, New York—Washigton, 1968; NMR Spectra
Catalog, Instrument Division Varian Associates, Palo Alto
(California), 1962.
17. M. Koremura, H. Oku, T. Shono, and T. Nakanishi,
Takamine Kenkyusho Nempo, 1961, 13, 198; Chem. Abstrs.,
1962, 57, 16450.
18. D. Pirillo, G. Rescia, G. Traverso, and A. De Paoli,
Farmaco Ed. Sci., 1980, 35, 324; Chem. Abstrs., 1980, 93,
70965.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 00ꢀ03ꢀ32871),
the State Foundation for the Support of Leading Scienꢀ
tific Schools of Russia (Project No. 00ꢀ15ꢀ97328), and
the Ministry of Industry, Science, and Technology (State
Contract No. 402ꢀ2.2/3.3/8.1/19.1/21.1/22.4(00)ꢀP).
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Received October 24, 2002
in revised form January 24, 2003