Reaction of tellurium tetrachloride with propargyl halides

Article abstract of DOI:10.1134/S1070428015090055

The reaction of tellurium tetrachloride with propargyl bromide in boiling benzene regio- and stereoselectively afforded bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl]tellurium dichloride which was readily reduced to bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl] telluride. Propargyl chloride reacted with tellurium tetrachloride preliminarily stored for several months (and containing decomposition products) to give a mixture of bis[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride and regioisomeric [(Z)-1,3-dichloroprop-1-en-2-yl]- [(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride at a ratio of 3: 2, whereas the latter was formed as the sole product in the reaction with freshly prepared tellurium tetrachloride. Reduction of the regioisomer mixture produced the corresponding tellurides. The structure of the isolated compounds was confirmed by 1H, 13C, and 125Te NMR spectra.

Full text of DOI:10.1134/S1070428015090055

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 9, pp. 1249–1252. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.V. Martynov, N.A. Makhaeva, L.I. Larina, S.V. Amosova, 2015, published in Zhurnal Organicheskoi Khimii, 2015, Vol. 51, No. 9,
pp. 1275–1278.
Reaction of Tellurium Tetrachloride with Propargyl Halides
A. V. Martynov, N. A. Makhaeva, L. I. Larina, and S. V. Amosova
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: amosova@irioch.irk.ru
Received July 4, 2015
Abstract—The reaction of tellurium tetrachloride with propargyl bromide in boiling benzene regio- and
stereoselectively afforded bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl]tellurium dichloride which was readily
reduced to bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl] telluride. Propargyl chloride reacted with tellurium tetra-
chloride preliminarily stored for several months (and containing decomposition products) to give a mixture of
bis[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride and regioisomeric [(Z)-1,3-dichloroprop-1-en-2-yl]-
[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride at a ratio of 3:2, whereas the latter was formed as the sole
product in the reaction with freshly prepared tellurium tetrachloride. Reduction of the regioisomer mixture
produced the corresponding tellurides. The structure of the isolated compounds was confirmed by 1H, 13C, and
125Te NMR spectra.
DOI: 10.1134/S1070428015090055
We previously reported on the synthesis of bis-
[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride
and bis[(Z)-2,3-dichloroprop-1-en-1-yl] telluride via
regio- and stereoselective addition of tellurium tetra-
chloride to propargyl chloride and subsequent reduc-
tion of the resulting tellurium dichloride with sodium
metabisulfite [1]. Unlike reactions of propargyl halides
with sulfur dichloride [2] and selenium dichloride and
dibromide [2, 3], which followed the anti-Markovni-
kov addition pattern, tellurium tetrachloride reacted
with propargyl chloride under analogous conditions [1]
to produce only the Markovnikov syn adduct. It is
known that tellurium tetrahalides add to terminal
alkynes exclusively according to Markovnikov [4, 5].
However, the anti-Markovnikov adduct was obtained
in the reaction of TeCl4 with trimethylsilylacetylene
[4, 5], which suggests that anti-Markovnikov adducts
can be selectively obtained by reactions of tellurium
tetrahalides with alkynes. In continuation of our
studies on reactions of tellurium tetrachloride with
propargyl halides, the present work was aimed at
synthesizing analogs of bis[(Z)-2,3-dichloroprop-1-en-
1-yl]tellurium dichloride and bis[(Z)-2,3-dichloroprop-
1-en-1-yl] telluride containing bromomethyl groups
with a more nucleofugal bromine atom.
The reaction of tellurium tetrachloride with excess
propargyl bromide in boiling benzene (reaction time
18 h) was regio- and stereoselective, and the product
was the corresponding Markovnikov syn adduct, bis-
[(Z)-3-bromo-2-chloroprop-1-en-1-yl]tellurium di-
chloride (1, 83%). The subsequent reduction of 1 with
sodium metabisulfite gave 84% of bis[(Z)-3-bromo-2-
chloroprop-1-en-1-yl) telluride (2) (Scheme 1).
1
The structure of 1 and 2 was confirmed by the H,
13C, and 125Te NMR data, as well as by the mass spec-
trum of 2 which contained no molecular ion peak but
fragment ion peaks with m/z 282 [M – CH=CClCH2Br –
H]+ and 153 [CH=CClCH2Br]+. Compounds 1 and 2
1
displayed in the H NMR spectra signals from vinylic
and methylene protons, and the =CHCl signal of 1 ap-
peared in a weaker field relative to the corresponding
signal of 2, while the chemical shifts of the methylene
protons in 1 and 2 were almost similar. Analogous
pattern was observed in the 13C NMR spectrum where
the doublet of triplets belonging to the sp2-carbon atom
Scheme 1.
PhH
Na2S2O5, PhH–H2O
Br
Te
Cl Cl
1
Br
Br
Te
Br
Br
2
+ TeCl4
HC
Cl
Cl
Cl
Cl
2
1249

MARTYNOV et al.
1250
Scheme 2.
Cl
Cl
HC
PhH
≡
CCH2Cl
Cl
TeCl4, PhH
Cl
Te
Cl
Te
Cl
Cl
Te
Cl
+
HC
Cl Cl
Cl Cl
Cl Cl
Cl
Cl
Cl
Cl
A
3
4
Scheme 3.
Cl
Cl
Na2S2O5, PhH–H2O
Cl
Te
Cl Cl
+
Te
3
+
4
Cl
Cl
Cl
5
6
ride (5) and (Z)-1,3-dichloroprop-1-en-2-yl (Z)-2,3-di-
chloroprop-1-en-1-yl telluride (6) at the same ratio
(3:2) in an overall yield of 75%.
of 1 was also displaced downfield relative to the =CH
signal of 2; the positions of the CH2 signals (t.d.) in the
spectra of both compounds almost coincided with each
other. Fine structure analysis of the 13C NMR spectra
clearly indicated the formation of Markovnikov
adducts: as followed from the direct 13C–1H coupling
constants for =CH carbon nuclei [1JCH = 185 (1),
170.6 Hz (2)], that carbon atom is linked to the
chalcogen atom [6]. The same is proved by the direct
13C–125Te coupling constant (1JCTe = 297 Hz [7–10]) in
the 13C NMR spectrum of 2. The Z,Z configuration of
the double bonds in 1 and 2 was assigned on the basis
of the 13C–1H coupling constants between the methy-
The formation of isomeric tellurium dichloride 4
and telluride 6 in the above reactions was confirmed
1
1
by the H, 13C, and 125Te NMR data. In the H NMR
spectra (DMSO-d6), the =CHTe and =CHCl vinylic
protons resonated, respectively, at δ 8.32 and 7.66 ppm
for 4 and δ 7.30 and 6.84 ppm for 6. The correspond-
ing carbon signals appeared in the 13C NMR spectra as
doublets of triplets at δC 129.28 and 138.12 ppm (4)
and δC 110.00 and 131.58 ppm (6). Analysis of the
direct 13C–1H coupling constants clearly showed that
the downfield carbon signal belongs to the carbon
atom linked to tellurium [1JCH = 188.3 (4), 173.6 Hz
(6)] and that the upfield signal belongs to the carbon
atom linked to chlorine [1JCH = 206 (4), 204.2 Hz (6)]
[6]. Furthermore, this assignment was confirmed by
the 13C–125Te coupling constants for the =CHTe and
lene carbon atom and =CH hydrogen atom (3JCH
=
4 Hz) [11]. In addition, the 2D 1H NOESY spectrum of
2 showed cross peaks between the vinylic and methy-
lene protons.
Tellurium dichloride 1 is stable, and no its iso-
merization occurred on prolonged heating in boiling
benzene (for 25 h).
=CHCl carbon atoms in 4 (1JCTe = 300.8 Hz and 2JCTe
=
35.3 Hz, respectively) [7–10]. The methylene carbon
atoms resonated in the 13C NMR spectra of 4 and 6 as
triplets of doublets. The presence of cross-peaks
between the vinylic and methylene protons of both
Further study of the reaction of tellurium tetra-
chloride with propargyl chloride has revealed that the
reaction course is influenced by impurities present in
tellurium tetrachloride. The reaction is regio- and
stereoselective [1] with tellurium tetrachloride pre-
pared by the chlorination of tellurium with sulfuryl
chloride [12]. When we used commercial TeCl4 (from
Aldrich) preliminarily stored for several months in
a refrigerator, we obtained 93% of a mixture of bis-
[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride
(3) and regioisomeric [(Z)-1,3-dichloroprop-1-en-2-
yl][(Z)-2,3-dichloroprop-1-en-1-yl]tellurium dichloride
(4) at a ratio of 3:2 (Scheme 2).
1
propenyl groups in the 2D H NOESY spectra in-
dicated their cis orientation with respect to the C=C
double bond.
The formation of unsymmetrical Markovnikov/
anti-Markovnikov adducts together with symmetrical
bis-anti-Markovnikov adducts was observed by us pre-
viously in the electrophilic addition of sulfur dichlo-
ride to propargyl halides [2]. Isomeric tellurium
dichloride 4 is likely to be formed via addition of
primary 1:1 adduct A to the second propargyl chloride
molecule both according and contrary to the Markov-
nikov rule with gradual accumulation of the anomalous
anti-Markovnikov adduct (Scheme 2). This mechanism
The reduction of a mixture of 3 and 4 in benzene
with an aqueous solution of sodium metabisulfite gave
a mixture of bis[(Z)-2,3-dichloroprop-1-en-1-yl] tellu-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

REACTION OF TELLURIUM TETRACHLORIDE WITH PROPARGYL HALIDES
1251
is supported by gradual increase of the intensity of
signals of both isomers 3 and 4 with simultaneous
decrease of the intensity of the vinylic proton signal of
δ, ppm 4.27 s (4H, CH2), 7.88 s (2H, =CHTe).
13C NMR spectrum (CDCl3), δC, ppm: 32.43 t.d (CH2,
3
1
1JCH = 156.5, JCH = 4 Hz), 125.50 d.t (=CHTe, JCH
=
3
2
1
185, JCH = 4 Hz), 144.28 q (=CCl, JCH = 4.5 Hz).
125Te NMR spectrum (CDCl3): δTe 687.2 ppm, t
(2JTeH = 6.5 Hz). Found, %: C 14.27; H 1.47; Cl 27.93;
Br 31.38; Te 24.75. C6H6Cl4Br2Te. Calculated, %:
C 14.20; H 1.19; Cl 27.95; Br 31.50; Te 25.15.
M 507.33.
intermediate adduct A in the H NMR spectra of the
reaction mixture. On the other hand, tellurium dichlo-
ride 3 remained intact on heating in boiling benzene
for several days, which ruled out its isomerization into
4. The sharp increase of the rate of the anomalous anti-
Markovnikov addition in the second step of the reac-
tion with commercial tellurium tetrachloride may be
rationalized by the presence of decomposition products
(in a sample stored for a long time) such as tellurium
oxychloride, tellurium dioxide, HCl, and other micro
impurities that can catalyze this process. Freshly pre-
pared tellurium tetrachloride contains no such im-
purities, and its reaction with propargyl chloride is
regio- and stereoselective.
Bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl] tellu-
ride (2). A solution of 2.49 g (11.2 mmol) of Na2S2O5
in 6 mL of water was added to a solution of 0.569 g
(1.12 mmol) of tellurium dichloride 1 in 20 mL of
benzene, and the mixture was stirred for 12 h at room
temperature. The benzene layer was separated, the
aqueous layer was extracted with chloroform, the
extract was combined with the organic phase and dried
over MgSO4, and the solvent was removed under
reduced pressure. Yield 0.409 g (84%), white powder,
Thus, our results have revealed loss of regioselec-
tivity in the reaction of propargyl chloride with com-
mercial tellurium tetrachloride (Aldrich) preliminarily
stored for several months at –4°C and hence con-
taining decomposition products. In this case, a 3:2
mixture of the symmetrical bis-Markovnikov adduct
and unsymmetrical Markovnikov/anti-Markovnikov
adduct is formed.
1
mp 75–77°C. H NMR spectrum (CDCl3), δ, ppm:
4.22 s (4H, CH2), 7.31 s (2H, =CHTe). 13C NMR spec-
1
trum (CDCl3), δC, ppm: 35.66 t.d (CH2, JCH = 155.9,
3JCH = 4.2 Hz), 109.46 d.t (=CHTe, 1JTeC = 297, 1JCH
170.6, JCH = 4.2 Hz), 136.20–136.36 m (=C, JTeC
=
=
3
2
40 Hz). 125Te NMR spectrum (CDCl3): δTe 543.1 ppm,
t (2JTeH = 6.2 Hz). Mass spectrum, m/z (Irel, %): 282 (6)
[M – CH=CClCH2Br – H]+, 234 (4), 190 (12), 153 (50)
[CH=CClCH2Br]+, 127 (19), 117 (24), 109 (27), 83
(100). Found, %: C 16.81; H 1.59; Br 36.31; Cl 15.93;
Te 29.46. C6H6Cl2Br2Te. Calculated, %: C 16.51;
H 1.39; Br 36.62; Cl 16.25; Te 29.24. M 436.42.
EXPERIMENTAL
The 1H (400.13 MHz), 13C (100.61 MHz), and 125Te
(76.30 MHz) NMR spectra were recorded on a Bruker
DPX-400 spectrometer using tetramethylsilane (1H,
13C) or Me2Te (125Te) as internal standard. The mass
spectrum of 2 was obtained using an Agilent 5975
mass-selective detector (electron impact, 70 eV). The
spectral studies were performed using the equipment
of the Baikal Joint Analytical Center, Siberian Branch,
Russian Academy of Sciences.
Reaction of propargyl chloride with tellurium
tetrachloride. A solution of 1.350 g (5 mmol) of TeCl4
and 2.250 g (30 mmol) of propargyl chloride in 25 mL
of benzene was heated for 14 h under reflux with
stirring. The precipitate was filtered off, the solvent
and excess propargyl chloride were removed under
reduced pressure, and the residue was washed with
hexane and dried under reduced pressure. Yield
1.624 g (93%), a mixture of compounds 3 and 4 at
a ratio of 3:2 (according to the 1H NMR data).
Propargyl chloride was prepared by chlorination of
propargyl alcohol with thionyl chloride in benzene
[13]. Tellurium tetrachloride was either commercial
product (Aldrich) or prepared by chlorination of
tellurium with sulfuryl chloride [12].
Bis[(Z)-2,3-dichloroprop-1-en-1-yl]tellurium
1
Bis[(Z)-3-bromo-2-chloroprop-1-en-1-yl]telluri-
um dichloride (1). A solution of 1.900 g (7.1 mmol) of
TeCl4 and 5.158 g (43.4 mmol) of propargyl bromide
(a 80% solution in toluene) in 55 mL of benzene was
heated for 18 h under reflux. The black solid was
filtered off, and the solvent and excess propargyl
bromide were removed from the filtrate under reduced
pressure. Yield 2.987 g (83%), brown powder,
mp 103–105°C (decomp.). 1H NMR spectrum (CDCl3),
dichloride (3). H NMR spectrum, δ, ppm: in CDCl3:
4.38 d (4H, CH2, 3J = 1.2 Hz), 7.94 t (2H, =CHTe, 3J =
1.2 Hz); in DMSO-d6: 4.76 s (4H, CH2), 8.52 s (2H,
=CHTe); published data [1]: 4.75 s (4H, CH2), 8.51 s
(2H, =CH). 13C NMR spectrum (DMSO-d6), δC, ppm:
47.25 t.d (CH2, 1JCH = 157.0, 3JCH = 4.0 Hz), 127.02 d.t
1
3
1
(=CHTe, JCH = 188.3, JCH = 3.6, JTeC = 258 Hz),
2
143.04 s (=C, JTeC = 44.4 Hz); published data [1]:
47.03 (CH2), 127.08 (=CHTe, JTeC = 260 Hz), 143.08
1
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

MARTYNOV et al.
1252
(C=). 125Te NMR spectrum (DMSO-d6): δTe 723.5 ppm
(δTe 724 ppm [1]).
(=CHTe, JCH = 173.6, JCH = 4.2 Hz), 131.58 d.t
1
3
1
3
(=CHCl, JCH = 204.2, JCH = 5.8 Hz), 135.08 s (=C),
135.08 s (=C). 125Te NMR spectrum (CDCl3):
δTe 635.4 ppm. Found, %: C 20.30; H 1.85; Cl 41.12;
Te 36.46. C6H6Cl4Te. Calculated, %: C 20.74; H 1.74;
Cl 40.81; Te 36.72. M 347.52.
[(Z)-1,3-Dichloroprop-1-en-2-yl][(Z)-2,3-dichloro-
1
prop-1-en-1-yl]tellurium dichloride (4). H NMR
spectrum, δ, ppm: in CDCl3: 4.38 s [2H, =C(Cl)CH2],
5.02 d [2H, =C(Te)CH2], 7.33 s (1H, =CHCl), 7.86 t
(1H, =CHTe); in DMSO-d6: 4.73 s [2H, =C(Cl)CH2],
4.95 s [2H, =C(Te)CH2], 7.66 s (1H, =CHCl), 8.32 s
(1H, =CHTe). 13C NMR spectrum (DMSO-d6), δC,
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 14-03-00185).
1
3
ppm: 46.95 t.d [=C(Te)CH2, JCH = 156.1, JCH
=
=
1
3
REFERENCES
4.0 Hz], 47.25 t.d [=C(Cl)CH2, JCH = 157.0, JCH
1
3
4.0 Hz], 129.28 d.t (=CHTe, JCH = 188.3, JCH = 4.0,
1JCTe = 300.8 Hz), 138.12 d.t (=CHCl, JCH = 206,
1
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2
2
44.4 Hz), 143.43 s (=C). 125Te NMR spectrum
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H 1.48; Cl 50.52; Te 30.76. C6H6Cl6Te. Calculated, %:
C 17.22; H 1.45; Cl 50.84; Te 30.50.
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(6.6 mmol) of Na2S2O5 in 7 mL of water was added to
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7.28 s (2H, =CHTe); published data [1]: 4.24 s (4H,
CH2), 7.25 s (2H, =CH). 13C NMR spectrum (CDCl3),
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3
δC, ppm: 48.45 t (CH2, JCH = 154.2, JCH = 4.0 Hz),
1
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(CDCl3), δ, ppm: 4.27 s [2H, =C(Te)CH2], 4.63 s [2H,
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1
3
[=C(Te)CH2, JCH = 154.2, JCH = 4.0 Hz], 47.33 t.d
1
3
[=C(Cl)CH2, JCH = 153.7, JCH = 8.4 Hz], 110.00 d.t
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015