Reactions of Lithium Acylates α-Carbanions with 1,2-Diiodoethane

Article abstract of DOI:10.1134/S1070363219010262

The interaction of lithium acylates α-carbanions (obtained via metallation of acetic, butyric, and isobutyric acids with lithium diisopropylamide) with 1,2-diiodoethane under argon in tetrahydrofuran at 20–25°C has proceeded as oxidative cross-coupling of enolate anions to form succinic, 2,3-diethylsuccinic, and 2,2,3,3-tetramethylsuccinic acids with yields 50, 53, and 16%, respectively. The products of sequential nucleophilic substitution of iodine atoms with alkyloxycarbonyl species have not been detected.

Full text of DOI:10.1134/S1070363219010262

ISSN 1070-3632, Russian Journal of General Chemistry, 2019, Vol. 89, No. 1, pp. 148–150. © Pleiades Publishing, Ltd., 2019.
Russian Text © A.V. Zorin, A.R. Chanysheva, A.O. Lenkova, V.V. Zorin, 2019, published in Zhurnal Obshchei Khimii, 2019, Vol. 89, No. 1, pp. 136–139.
LETTERS
TO THE EDITOR
Reactions of Lithium Acylates α-Carbanions
with 1,2-Diiodoethane
a
a
a
a
A. V. Zorin , A. R. Chanysheva *, A. O. Lenkova , and V. V. Zorin
a
Ufa State Petroleum Technological University, ul. Kosmonavtov 1, Ufa, 450062 Russia
e-mail: aliyach@mail.ru
*
Received May 31, 2018; revised May 31, 2018; accepted June 7, 2018
Abstract—The interaction of lithium acylates α-carbanions (obtained via metallation of acetic, butyric, and
isobutyric acids with lithium diisopropylamide) with 1,2-diiodoethane under argon in tetrahydrofuran at 20–25°C
has proceeded as oxidative cross-coupling of enolate anions to form succinic, 2,3-diethylsuccinic, and 2,2,3,3-
tetramethylsuccinic acids with yields 50, 53, and 16%, respectively. The products of sequential nucleophilic
substitution of iodine atoms with alkyloxycarbonyl species have not been detected.
Keywords: 1,2-diiodoethane, dicarboxylic acids, lithium acylates α-carbanions, metallation, oxidative cross-
coupling
DOI: 10.1134/S1070363219010262
It has been earlier shown that the reaction of
dibromoalkanes containing distant bromomethylene
groups with lithium acylates α-carbanions proceeds as
sequential nucleophilic substitution of bromine atoms
with the formation of the corresponding dicarboxylic
acids [1–4]. On the contrary, we have found that the
reaction of lithium acylates α-carbanions with 1,2-di-
bromoethane affords the products of oxidative coupling
of α-carbanions (the corresponding dicarboxylic
acids), except for the reaction of α-carbanion of
lithium acetate, in which both nucleophilic substitution
and oxidative coupling occur simultaneously, leading
to adipic and succinic acids, respectively [5].
The products composition suggested that, similarly
to the reaction of lithium acylates α-carbanions with
1,2-dibromoethane [5], 1,2-diiodoethane was involved
in the redox process with the formation of dicarboxylic
acids 6а–c, the products of oxidative coupling of
lithium acylates enolates 2а–c. 2,3-Diethylsuccinic
acid 6b was formed as a mixture of diastereomeric
meso- and (±)-forms in 2 : 1 ratio. The formation of the
reaction products could be explained by the scheme
including the stage of electron transfer from lithium
acylates 2а–2c to 1,2-diiodoethane 3 (Scheme 1).
A similar scheme of the formation of the products
of oxidative coupling of α-carbanions has been pre-
viously suggested for the reactions with other oxidants
Extending the above-mentioned studies, we
investigated the reaction of lithium acylates α-
carbanions with 1,2-diiodoethane. It was found that the
reaction of lithium acylates α-carbanions 2а–c
[5, 6].
Unlike the reaction of lithium acylates enolates
with 1,2-dibromoethane, in the case of 1,2-diiodo-
ethane, the formed iodoethyl radical 3b, apparently,
was completely eliminated yielding ethylene and
iodine atom, since ethyl iodide was not detected in the
reaction products; moreover, when performing the
reaction in the presence of a spin trap (hex-1-ene, as
described in [5, 7]), the expected spin-adduct of 3b and
hex-1-ene (octyl iodide) was not found. Iodine formed
in the course of the reaction was also involved in the
oxidative coupling, as described in [6, 8].
[prepared via metallation of acetic (1а), butyric (1b),
and isobutyric (1c) acids with lithium diisopropyl-
amide (LDA)] with 1,2-diiodoethane 3 under argon
atmosphere in THF at 20–25°C in the ratio of 2 : 3 =
2
: 1 afforded succinic (6а), 2,3-diethylsuccinic (6b),
and 2,2,3,3-tetramethylsuccinic (6c) acids with 50, 53,
and 16% yield, respectively (Scheme 1). As in the case
of 1,2-dibromoethane, ethylene was evolved in the
course of the reaction.
1
48

REACTIONS OF LITHIUM ACYLATES α-CARBANIONS WITH 1,2-DIIODOETHANE
149
Scheme 1.
I
R1
R2
R1
R2
I
R1
R2
+
2
LDA
Li
3
−
−
+
−
COOH
COO Li
COO
I
Li+
I
3
а
1
а−1c
2а−2c
4а−4c
R1
OLi
R1
R2
R1
R1
R1
R2
R1
2H+
+
_3а
3
COOLi
2
a−2c + 4а−4c
LiOOC
COOH
OLi
LiOOC
HOOC
R2
R2
R2
R2
5
а−5c
6а−6c
7а−7c
3
а
CH CH I
H
2
C CH ;
I+ I
2
I2
2
3
−I
−
LiI
3
b
I2
2H+
2а−2c
5а−5c
6а−6c
(c).
1
2
1
2
1
2
R = R = H (а); R = H, R = C
2
H
5
(b); R = R =CH
3
Besides, unlike the reaction of lithium acetate
enolate with 1,2-dibromoethane [5], in the case of 1,2-
diiodoethane, the product of sequential nucleophilic
substitution of the iodine atoms (adipic acid) was not
found, despite higher activity of iodoalkanes in the reac-
tions of nucleophilic substitution than bromoalkanes
Ethylene was detected as 1,2-dibromoethane after
trapping with bromine, as described in [5]. The
solution of bromine in carbon tetrachloride was
analyzed by GC and GCMS methods. Similarly, the
experiments in the presence of hex-1-ene were
performed, which was added in the flask together with
1,2-diiodoethane in equimolar amount.
[9, 10].
Comparison of the yields of dicarboxylic acids
Melting points of dicarboxylic acids coincided with
formed in the reactions of lithium acylates enolates
with 1,2-dibromo- and 1,2-diiodoethane showed that
the dependence of the yield of dicarboxylic acids on
the structure of lithium acylates α-carbanions was in
general retained (6b > 6а > 6c).
the reference data [11, 12].
1
Succinic acid (6а). mp 188–189°С. Н NMR
spectrum, δ, ppm: 2.40 s (4H, CH2). C NMR spec-
13
trum, δ , ppm: 28.54 (CH ), 179.63 (C=O). Mass spec-
С
2
trum, m/z (I , %): 101 (15), 100 (49), 74 (69), 72 (18),
rel
Reaction of carboxylic acids with 1,2-diiodo-
ethane. A solution of 0.01 mol of carboxylic acid
56 (36), 55 (95), 46 (10), 45 (100), 44 (41), 43 (15), 42
(13), 40 (15).
1
а–1c in 20 mL of anhydrous THF was added at
2
,3-Diethylsuccinic acid (6b). mp 127–133°С.
stirring under argon to a solution of 0.02 mol of LDA
in 30 mL of anhydrous THF cooled to 0–5°С. The
reaction mixture was heated to 35–40°С, stirred for
1
meso-2,3-Diethylsuccinic acid. Н NMR spectrum,
δ, ppm: 0.90 t (6Н, СН ), 1.52–1.70 m (2Н, СН ), 1.70–
.87 m (2Н, СН ), 2.63–2.70 m (2Н, СН). С NMR
spectrum, δ , ppm: 11.09 (СН ), 22.20 (СН ), 46.79
СН), 182.08 (C=O). Mass spectrum, m/z (I , %): 128
25), 101 (44), 100 (13), 99 (21), 88 (19), 87 (30), 84
50), 83 (34), 73 (37), 70 (20), 69 (75), 57 (10), 56
46), 55 (100), 53 (13), 45 (28), 44 (26), 43 (32), 42
43), 41 (65), 40 (16).
3
2
4
0 min, and then cooled to 20–25°С. 0.005 mol of 1,2-
13
1
2
diiodoethane 3 in 20 mL of anhydrous THF was then
added, and the mixture was stirred for 2 h. During the
reaction, the mixture turned dark due to the formation
of iodine. 30 mL of distilled water was added to the
formed mixture. The aqueous layer was treated with
С
3
2
(
(
(
(
(
rel
1
0% hydrochloric acid to рН = 1 and extracted with
diethyl ether (3×30 mL). The combined extracts were
dried over Na SO . After evaporation of ether, the
1
2
4
(±)-2,3-Diethylsuccinic acid. Н NMR spectrum, δ,
ppm: 1.05 t (6Н, СН ), 1.87–1.90 m (4Н, СН ), 2.70–
crystals of dicarboxylic acid 6а–6c were formed.
3
2
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 1 2019

1
50
ZORIN et al.
1
3
2
(
.80 m (2Н, СН). С NMR spectrum, δ , ppm: 13.03
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
REFERENCES
С
СН ), 22.36 (СН ), 48.48 (СН), 182.88 (C=O). Mass
3 2
spectrum, m/z (I , %): 128 (20), 101 (14), 100 (10), 99
rel
(
(
(
26), 88 (35), 87 (53), 84 (28), 83 (34), 73 (65), 70
33), 69 (100), 56 (36), 55 (88), 53 (12), 45 (28), 44
39), 43 (29), 42 (37), 41 (58), 40 (23).
1
. Durr, A.M, Jr., Eby, H.H., and Newman, M.S., USA
Patent 3210404, 1965, C. A., 1966, vol. 64, p. 1968d.
2
,2,3,3-Tetramethylsuccinic acid (6c). mp 170–
1
1
71°С. Н NMR spectrum, δ, ppm: 1.20 s (12Н, СН ).
C NMR spectrum, δ , ppm: 17.32 (СН ), 48.50 (С),
2. Chanysheva, A.R., Zorin, A.V., and Zorin, V.V., Bash.
Khim. Zh., 2015, vol. 22, no. 4, p. 53.
3
1
3
С
3
1
8
79.36 (С=О). Mass spectrum, m/z (I , %): 88 (100),
7 (10), 84 (49), 83 (25), 73 (52), 71 (14), 70 (46), 69
3. Kofron, W.G. and Hauser, C.R., J. Org. Chem., 1970,
rel
vol. 35, p. 2085. doi 10.1021/jo00831a107
(
(
80), 59 (34), 57 (10), 56 (15), 55 (30), 45 (19), 44
46), 43 (43), 42 (19), 41 (88), 40 (28).
4. Bahl, J.J., Bates, R.B., Beavers, W.A., and Mills, N.S.,
J. Org. Chem., 1976, vol. 41, p. 1620. doi 10.1021/
jo00871a030
1
,2-Dibromoethane. Mass spectrum, m/z (I , %):
rel
5
. Zorin, A.V., Zaynashev, A.T., Chanysheva, A.R., and
Zorin, V.V., Russ. J. Gen. Chem., 2015, vol. 85, no. 6,
p. 914. doi 10.1134/S1070363215060043
1
(
09 (94), 108 (4), 107 (100), 105 (3), 95 (4), 93 (5), 80
6), 78 (6), 44 (19), 40 (3).
1
13
6. Chanysheva, A.R., Zorin, A.V., and Zorin, V.V., Bash.
Khim. Zh., 2014, vol. 21, no. 2, p. 99.
Н and С NMR spectra were registered in СDCl +
3
CF COOH using a Bruker AM-300 spectrometer
3
1
13
7. Bilevich, K.А. and Okhlobystin O.Yu., Russ. Chem.
Rev., 1968, vol. 37, p. 954. doi 10.1070/
RC1968v037n12ABEH001716
[
300.13 ( Н) and 75.47 MHz ( С)]. Chromato–mass
spectrometry analysis was performed using a GCMS-
QP2010S Shimadzu instrument (electron ionization at
8
. Renaud, P. and Fox, M., J. Org. Chem., 1988, vol. 53,
7
0 eV, the range of detected masses 33–500 Da).
p. 3745. doi 10.1021/jo00251a015
Capillary column HP-1MS (30 m × 0.25 mm × 0.25 μm)
was used, temperature of injector – 280°C, temperature
of ionization chamber – 200°C. The analysis was
performed in temperature programming mode from 50
to 280°C with the rate 10 deg/min, carrier gas – helium
9
. Becker, H.G.O., Berger, W., Domschke, G., Fang-
hänel, E., Faust, J., Fischer, M., Gentz, F., Gewald, K.,
Gluch, R., Mayer, R., Müller, K., Pavel, D., Schmidt, H.,
Schollberg, K., Schwetlick, K., Seiler, E., et al.,
Organicum: Practical Handbook of Organic Chemistry,
Pergamon Press, 1973.
(
1.1 mL/min).
1
0. Raid, K., Course of Physical Organic Chemistry,
FUNDING
This study was financially supported by the
Ministry of Education and Science of Russian
Federation in the scope of the basic part of the State
task (no. 4.6451.2017/8.9).
Moscow: Mir, 1972.
11. Freidlin, G.N., Aliphatic Dicarboxylic Acids, Moscow:
Khimiya, 1978.
12. Eberson, L., Acta Chem. Scand., 1959, vol. 13, p. 40.
doi 10.3891/acta.chem.scand.13-0040
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 89 No. 1 2019