Synthesis of ketene phenyl- and butyltelluroacetals by a Horner-Wittig route

Article abstract of DOI:10.1016/j.tet.2005.05.085

New and efficient methods were developed to prepare ketene organyltelluroacetals in moderate to excellent yields. This was accomplished by reaction of phenyl- or butyltelluromethylphosphonates with phenyl- or butyltellurenyl halides and aldehydes or cyclo

Full text of DOI:10.1016/j.tet.2005.05.085

Tetrahedron 61 (2005) 7712–7718
Synthesis of ketene phenyl- and butyltelluroacetals
by a Horner–Wittig route
a
a
a
b
Claudio C. Silveira,a, Rodrigo Cella, Antonio L. Braga, Raquel G. Jacob, Eder J. Lenardao
*
˜
and Gelson Perinb,
*
a
´
Departamento de Quımica, Universidade Federal de Santa Maria, UFSM, C.P. 5001, 97105-900 Santa Maria, RS, Brazil
b
´
Departamento de Quımica, Universidade Federal de Pelotas, UFPel, PO Box 354, 96010-900 Pelotas, RS, Brazil
Received 31 March 2005; revised 25 May 2005; accepted 26 May 2005
Available online 17 June 2005
Abstract—New and efficient methods were developed to prepare ketene organyltelluroacetals in moderate to excellent yields. This was
accomplished by reaction of phenyl- or butyltelluromethylphosphonates with phenyl- or butyltellurenyl halides and aldehydes or
cyclohexanone, under basic conditions. This Horner–Wittig protocol allows the preparation of several new tri- and tetra-substituted olefins.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
Vinyl tellurides have recently been recognized as important
synthetic reagents and intermediates, because they are used
in a variety of carbon–carbon bond forming reactions.1,2
Scheme 1. High functionality of ketene organyltelluroacetals 1.
The most useful reaction of vinyl tellurides involves
transmetallation by treatment with lithium,3 Li/Ce,3a Li/
Zn,4 sodium,5 copper,3g,6 zinc,7 and calcium organyls5 as
well as with Grignard reagents,3a,8 followed by the capture
of the resulting vinyl anion with electrophiles. An important
characteristic of this metal/metalloid exchange is that, in the
majority of these reactions, the geometry of the original
double bound is retained.1 More recently, very useful
applications of vinyl tellurides have emerged as powerful
tools for C–C bond construction: the homocoupling9 of
vinyl tellurides and their direct cross-coupling reactions
with terminal alkynes,10 Grignard reagents,11 alkylzinc7a
and alkynylzinc derivatives.7b These are efficient protocols
to prepare conjugated dienes, enynes and enediynes. The
coupling can be catalyzed by palladium,7a,b,10,11 Ni(II)10b,11
or Co(II).11a,d Vinyl tellurides can also react with carbon
monoxide in presence of Pd(II) salts to produce a,b-
unsaturated acids, esters and butenolides.12,13 In this way,
ketene organyltelluroacetals 1, are very useful both as vinyl
1,1-dianions3i,14 or as vinyl 1,1-dicarbocation15 equivalents
in Te/Metal exchanges and in cross-coupling reactions,
respectively (Scheme 1).
When ketene organyltelluroacetals 1 were submitted to
Pd(II)-catalyzed cross-coupling with terminal alkynes,15
only the butyltelluroacetals afforded the respective ene-
diynes in good yields. This observation is related to a
previous report3e indicating that vinylaryltellurides gave
mixtures of vinyl- and aryllithiums by transmetallation with
alkyllithiums.
In spite of the high synthetic potential of ketene
organyltelluroacetals, up to recent times these compounds
were virtually unknown.16
To our knowledge, the only methods described for their
preparation involve the hydrozirconation of acetylenic
tellurides followed by transmetallation using a butyltellur-
enyl halide16a,b and the reaction of vinylcarbenes with
diphenyl ditelluride (only two examples, in low yields).16c
Moreover, the preparation of ketene telluroacetals with
chain elongation is not possible by using these methods,
which obviously limits their application in organic
synthesis.
Keywords: Wittig reaction; Aldehydes; Ketene telluroacetals; Tellurium
and compounds.
*
Corresponding authors. Tel./fax: C55 55 220 8754 (C.C.S.); tel./fax:
C55 53 275 7354 (G.P.); e-mail addresses: silveira@quimica.ufsm.br;
gelson_perin@ufpel.edu.br
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.05.085

C. C. Silveira et al. / Tetrahedron 61 (2005) 7712–7718
7713
In the last years, our group has described practical and
efficient methodologies for the preparation of vinyl
chalcogenides based on Wittig and Horner–Wittig
reactions,17,18 including preliminary results on the synthesis
of ketene phenyltelluroacetals by a Horner–Wittig
methodology.16d
(Scheme 2).19 Treatment of 2 with LDA and phenyl-
tellurenyl bromide 4 in THF, generated the lithiated species
5 which, upon reaction with aldehydes or cyclohexanone,
afforded ketene phenytelluroacetals 6a–g, in a one-pot
process (without isolation of intermediates), as depicted in
Scheme 2. In most cases, good to excellent yields (72–94%)
were obtained by using aromatic and aliphatic aldehydes
(entries 1–5, Table 1). However, the reactions performed
with acrolein and cyclohexanone gave the corresponding
products in noticeably lower yields (entries 6 and 7,
Table 1).
Due to our continuous interest on vinylic tellurium species,
we describe here a full account on the synthesis of ketene
phenyltelluroacetals and also a study of the synthesis of
ketene butyltelluroacetals employing the same strategy.
It was observed that the use of an excess of the
phenyltelluromethylphosphonate 2 was required to afford
6a–g in good yields. For example, reaction of 1.3 equiv of 2
with C6H5TeBr, followed by the addition of furfural,
provided 6b in 30% yield (entry 1, Table 2), while the
yields increased to 64, 78 and 94% when 1.5, 1.7 and
2.0 equiv of 2, were, respectively, employed (entries 2–4,
Table 2). Therefore, and in view of the easy preparation of
2, an excess (2 equiv) was used for the present study.
Alternatively, compounds 6a–g could be obtained directly
from 3, by reacting with LDA, phenyltellurenyl bromide 4
and then with the required carbonyl compound (Scheme 2).
However, despite being an easier procedure, yield of 6b was
not satisfactory (entry 5, Table 2).
2. Results and discussion
2.1. Preparation of ketene phenyltelluroacetals
Phenyltelluromethylphosphonate 2, a reagent available on
large scale and easily obtained in good yields by the reaction
of diethyl methylphosphonate anion 3-Li and phenyl-
tellurenyl bromide 4, was selected as starting material
A very interesting feature was the fact that the correspond-
ing vinyl telluride, a possible by-product resulting from the
direct reaction of the anion derived from 2 with aldehydes,
was not formed under the employed conditions (reactions at
room temperature). It has been described that sodium salts
Scheme 2. Synthesis of ketene phenyltelluroacetals.
Table 1. Preparation of ketene bis(phenyltelluro) acetals 6 employing the strategy of Scheme 2
Entry
R
R1
H
Product 6
Reaction time
(h)a
Yields (%)b
1c
C6H5
1
1
88
6a
2
2-Furyl
H
94
6b
6c
6d
3d
4-NO2C6H4
H
H
1
2
72
94
4
CH3CH2CH2
5
(CH3)2CH
CH2CH
H
H
2
84
6e
6
7
2
2
41
16
6f
–CH2(CH2)3CH2–
6g
a At room temperature.
b Isolated yields by column chromatography.
c Mp 67.9–69.2 8C (hexane).
d Mp 81.9–82.9 8C (hexane).

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C. C. Silveira et al. / Tetrahedron 61 (2005) 7712–7718
Table 2. Reaction of 2 or 3 with furfural to afford 6b
Entry
Molar equivalents
LDA
2
3
C6H5TeBr
Yield (%)
1
2
3
4
5
1.3
1.5
1.7
2.0
—
—
—
—
—
1
2.4
2.6
2.8
3.1
3.1
1
1
1
1
2
30
64
78
94
45
of tellurophosphonates 2 required reflux in THF to react
with aromatic aldehydes.19 As a result of the more effective
stabilizing capability of two C6H5Te groups the lithium
intermediate 5 reacts with aromatic and aliphatic aldehydes
and cyclohexanone at room temperature to give the desired
products 6a–g.
HMPA as co-solvent (entries 2 and 3, Table 3). It was also
observed that the yields were highly dependent upon the
amounts of 7 and LDA (entries 4–6, Table 3), with the best
results achieved by using 4 equiv of 7, 5.1 equiv of LDA
and only 1 equiv of C4H9TeI (entry 6, Table 3).
Although these large amounts of 7 and LDA could allow the
generation of a great excess of the intermediate 8, the
formation of vinyl tellurides derived from the reaction of
this species with the carbonyl compounds were not
observed. Thus, 1-butyltelluro-2-phenylethene was not
detected when benzaldehyde was employed, even in the
presence of HMPA and under reflux. This observation
reflects the greater reactivity of the phenyltelluro-phospho-
nate 2 when compared with its congener butyl telluro-
phosphonate 7.19
2.2. Preparation of ketene butyltelluroacetals
In view of the known cleaner Metal/Te exchange and cross-
coupling reactions of vinyl butyltellurides as compared with
their phenyltelluride analogs,3e,15 we decided to perform a
study on the preparation of ketene butyltelluroacetals by our
Horner–Wittig route. In this way, treatment of butyltelluro-
methylphosphonate19 7 with LDA generated the lithiated
species 8, which upon reaction with butyltellurenyl iodide 9
in THF afforded the bis(butyltelluro)phosphonate inter-
mediate 10, as depicted in Scheme 3. The deprotonation of
10 at the expense of excess of base used, followed by the
reaction with a carbonyl compound, gave the desired
product 12 in a one-pot process (Scheme 3). Similar results
were observed when C4H9TeBr [obtained in situ by the
addition of Br2 to a solution of (C4H9Te)2 in THF] was used.
The need of larger amounts of 7 can be explained by the
lower reactivity of its anion 8-Li towards tellurenyl halides
(Scheme 3), when compared with 2-Li. This characteristic is
evidenced in the preparation of the organyltellurophos-
phonates 2 and 7 (Scheme 4). While phenyltellurophos-
phonate 2 can be prepared by the direct telluration of 3-Li
with phenyltellurenyl halides, no reaction was observed
For the reactions described in Scheme 3, a detailed study of
the experimental conditions was performed using benz-
aldehyde as the carbonyl component. By employing the
optimal conditions described above for preparation of
the phenyltellurium analogs 6a–g (2 equiv of 7, THF, rt),
the yield of 12a was unsatisfactory (entry 1, Table 3). We
observed that a larger excess of the butyltellurophosphonate
7 and HMPA (1 mL) was required to afford good yields of
the products 12a–h. For example, benzaldehyde reacted
with 4 equiv of 7 using THF as solvent, providing 12a in
28% yield, while the yield increased to 72% by addition of
Scheme 4. Synthesis of organyltellurophosphonates.
Scheme 3. Synthesis of ketene butyltelluroacetals.
Table 3. Synthesis of 12a by reaction of 7 with benzaldehyde
Entry
Molar equivalents
7
LDA
C4H9TeI
HMPA (mL)
Yield (%)
1
2
3
4
5
6
7
2
4
4
2
3
4
3
3.1
6.1
6.1
3.1
4.1
5.1
5.1
1
2
2
1
1
1
2
—
—
26
28
72
29
54
75
53
1.0
1.0
1.0
1.0
1.0

C. C. Silveira et al. / Tetrahedron 61 (2005) 7712–7718
7715
Table 4. Preparation of ketene bis(butyltelluro) acetals 12 employing the strategy of Scheme 3
Entry
R
R1
Product 12
Reaction time
(h)a
Yields (%)b
1
2
3
C6H5
H
H
H
2
2
2
75
70
63
12a
12b
4-MeC6H4
4-ClC6H4
12c
12d
12e
12f
4
5
6
CH3CH2CH2
CH3(CH2)2CH2
CH3(CH2)4CH2
H
H
H
3
3
3
87
91
92
7
H
3
3
90
34
12g
12h
8
–CH2(CH2)3CH2–
a At room temperature.
b Isolated yields by column chromatography.
when butyltelluryl halides were added to 3-Li. To
circumvent this problem, an alternative procedure was
envisaged to prepare 7, based on the substitution reaction
of the corresponding iodomethyl phosphonate 13 by the
very nucleophilic lithium butyltellurolate in 55% yield
(Scheme 4).19
were performed on a 1.0 mmol scale, the reactions can also
be performed successfully on larger scales (e.g., 10 mmol)
with comparable yields. The compounds 12a–c (from the
reaction with aromatic aldehydes) could be easily purified
by column chromatography. However, the products 12d–h
were obtained as mixtures with dibutyl ditelluride,
inseparable by column chromatography. In these cases,
easy separations were achieved by converting the dibutyl
ditelluride into dibutyl telluride, by reduction with NaBH4/
EtOH and subsequent reaction with n-butyl bromide (see
Section 4).
However, the presence of the butyltellurium group in the
intermediate phosphonate 8-Li made it possible to react
with butyltellurenyl halides to afford the products 12 in the
presence of HMPA, via bis(butyltelluro)phosphonate 10.
A possible explanation for the difference of reactivity
between phenyltellurenyl- and butyltellurenyl halides in the
alkylation step described on Scheme 4 would be the higher
electrophilicity of the phenyltellurenyl group when
compared to butyltellurenyl and the largest steric hindrance
of the n-butyl group.20
3. Conclusions
Summarizing, we have developed a simple methodology for
the synthesis of new tri- and tetra-substituted ketene
bis(phenyltelluro) acetals and bis(butyltelluro) acetals.
Studies involving the chemical reactivity and use of these
species for the preparation of naturally occurring unsatu-
rated compounds are currently in progress.
Having in hands the best conditions for the reaction
described in Scheme 3, a detailed study was performed
with other carbonyl compounds with the results presented in
Table 4. In most cases, good to excellent yields (63–92%)
were obtained by using several aromatic and aliphatic
aldehydes (Table 4). The reaction of 7 with ketones was also
examined. Unfortunately, we only observed reaction with
cyclohexanone and in low yield (34%, entry 8, Table 4).
Other ketones such as acetophenone and 3-pentanone failed
to give the desired products. Although most experiments
4. Experimental
4.1. General remarks
The H and 13C NMR spectra of CDCl3 solutions were
recorded with a 80 MHz or a 200 MHz spectrometer, as
1

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C. C. Silveira et al. / Tetrahedron 61 (2005) 7712–7718
noted. Chemical shifts are expressed as parts per million
(ppm) downfield from tetramethylsilane as an internal
standard. Mass spectra (EI) were obtained at 70 eV with a
Hewlett Packard EM/CG HP-5988A spectrometer and
elemental analyses were performed with a Vario EL
Elementar Analysis System. Merck’s silica gel (230–
400 mesh) was used for flash chromatography. THF was
distilled over sodium/benzophenone immediately before
use. The aldehydes were distilled immediately before use.
7.1 Hz, 3H); 1.20–1.60 (m, 2H); 2.20 (q, JZ7.1 Hz, 2H);
6.61 (t, JZ7.0 Hz, 1H); 7.00–7.30 (m, 6H); 7.55–7.90 (m,
4H); 13C NMR (20 MHz, CDCl3) d 13.6, 22.0, 41.1, 80.2,
116.5, 118.1, 127.9, 129.1, 129.3, 138.6, 153.1. Anal. Calcd
for C17H18Te2: C, 42.76; H, 3.80. Found: C, 42.75; H, 3.70.
4.2.5. 1,1-Bis(phenyltelluro)-3-methyl-1-butene 6e. Yield
0.405 g (84%). MS m/z (rel. int.) 479 (MCK3, 12.0), 207
(2.0), 145 (100.0), 77 (34.0). H NMR (80 MHz, CDCl3) d
1
0.95 (d, JZ6.4 Hz, 6H); 2.30–3.00 (m, 1H); 6.44 (d, JZ
8.8 Hz, 1H); 7.00–7.30 (m, 6H); 7.55–7.80 (m, 4H); 13C
NMR (20 MHz, CDCl3) d 21.9, 39.0, 127.9, 128.0, 129.1,
129.3, 138.4, 138.7, 160.4. Anal. Calcd for C17H18Te2: C,
42.76; H, 3.80. Found: C, 42.81; H, 3.73.
4.2. General procedure for the synthesis of ketene
bis(phenyltelluro) acetals 6
To a solution of LDA (3.1 mmol) in THF (4 mL) cooled to
K78 8C, under nitrogen, was added dropwise a solution of 2
(0.71 g, 2 mmol) in THF (1 mL). The reaction was warmed
up to 0 8C and stirred 30 min at this temperature. Then, the
reaction flask was cooled to K78 8C and C6H5TeBr
(1 mmol, prepared in situ from C6H5TeTeC6H5 and Br2)
in THF (2 mL) was added. At the beginning, the C6H5TeBr
consumption was fast but at the end of the addition, a
slightly red solution remained which turns yellow in ca.
20 min. The temperature was again raised to 0 8C for
30 min, the carbonyl compound (1 mmol) in THF (1 mL)
was added and the reaction mixture stirred for 1–2 h at room
temperature (see Table 1). The reaction was quenched by
addition of water and extracted with ethyl acetate (3!
25 mL). The organic layer was dried over MgSO4 and the
solvent removed under vacuum. The residue was purified by
column chromatography (SiO2) using hexanes as eluent.
Spectral data of 6a–g are listed below.
4.2.6. 1,1-Bis(phenyltelluro)-1,3-butadiene 6f. Yield
0.191 g (41%). MS m/z (rel. int.) 464 (MCK2, 3.8), 207
(21.5) 77 (100.0). H NMR (80 MHz, CDCl3) d 5.07 (dd,
1
JZ15.5, 2.5 Hz, 1H); 5.11 (dd, JZ10.2, 2.5 Hz, 1H); 6.34–
6.79 (m, 1H); 6.96 (d, JZ10.0 Hz, 1H); 7.03–7.40 (m, 6H);
7.62–7.82 (m, 4H); 13C NMR (20 MHz, CDCl3) d 116.2,
118.4, 118.6, 128.1, 128.5, 129.2, 129.6, 138.1, 139.4,
139.6, 147.6. Anal. Calcd for C16H14Te2: C, 41.64; H, 3.06.
Found: C, 41.47; H, 2.94.
4.2.7. 1,1-Bis(phenyltelluro)-2-cyclohexanyl-ethene 6g.
Yield 0.081 g (16%). MS m/z (rel. int.) 506 (MCK2,
13.2), 299 (9.0), 77 (100.0). H NMR (80 MHz, CDCl3) d
1
1.35–1.55 (m, 6H); 2.50–2.75 (m, 4H); 7.00–7.30 (m, 6H);
7.61–7.49 (m, 4H). Anal. Calcd for C19H20Te2: C, 45.32; H,
4.00. Found: C, 45.31; H, 3.99.
4.2.1. 1,1-Bis(phenyltelluro)-2-phenyl-1-ethene 6a. Yield
0.454 g (88%). MS m/z (rel. int.) 514 (MCK2, 9.2), 309
(10.9), 207 (49.0), 77 (100.0). 1H NMR (80 MHz, CDCl3) d
7.00–7.50 (m, 11H); 7.60 (s, 1H); 7.65–7.93 (m, 4H); 13C
NMR (20 MHz, CDCl3) d 85.8, 116.1, 118.1, 127.5, 128.1,
128.9, 129.5, 139.4, 140.6, 140.9, 145.7. Anal. Calcd for
C20H16Te2: C, 46.96; H, 3.15. Found: C, 46.83; H, 3.22.
4.3. General procedure for the synthesis of ketene
bis(butyltelluro) acetals 12
To a solution of LDA (5.1 mmol) in THF (4 mL) cooled to
K78 8C, under nitrogen, was added, dropwise, a solution of
7 (1.34 g, 4 mmol) in THF (2 mL). The reaction was
warmed up to 0 8C and stirred 30 min at this temperature.
The reaction flask was cooled to K78 8C, and BuTeI
(1 mmol, prepared in situ from C4H9TeTeC4H9 and I2) in
THF (2 mL) was added. At the beginning, the tellurenyl
halide consumption was fast, and at the end of the addition,
a slightly red solution remained, which turns yellow in ca.
20 min. The temperature was again raised to 0 8C for
30 min, the carbonyl compound (1 mmol) in HMPA (1 mL)
was added and the reaction mixture stirred for 2–3 h at room
temperature (see Table 4). The reaction was quenched by
addition of water and extracted with ethyl acetate (3!
25 mL). The organic layer was dried over MgSO4 and the
solvent removed under vacuum. The residue was purified by
column chromatography (SiO2) and eluted with hexanes,
yielding 12a–c (pure materials) and 12d–h [mixture with
(C4H9Te)2]. For the products 12d–h, the mixture was
transferred to a Erlenmeyer flask, diluted with ethyl acetate
(10 mL), 95% ethanol (5 mL) and water (10 mL). Then,
n-butylbromide (0.11 mL, 1.0 mmol) and NaBH4 (0.038 g,
1 mmol) were added (to transform the dibutylditelluride into
the corresponding dibutyltelluride, which is more easily
removed by distillation). After this treatment, the product
was extracted with ethyl acetate (3!20 mL) and washed
with water, the organic phase was dried over anhydrous
MgSO4 and the solvent evaporated under reduced pressure.
4.2.2. 1,1-Bis(phenyltelluro)-2-(2-furyl)-1-ethene 6b.
Yield 0.476 g (94%). MS m/z (rel. int.) 503 (MCK3, 9.0),
205 (20.0), 77 (100.0). 1H NMR (80 MHz, CDCl3) d 6.10 (d,
JZ3.4 Hz, 1H); 6.33 (dd, JZ3.4 Hz, 1H); 7.10–7.33 (m,
7H); 7.42 (s, 1H); 7.62–7.75 (m, 2H); 7.80–8.00 (m, 2H);
13C NMR (20 MHz, CDCl3) d 83.0, 108.8, 111.2, 116.7,
117.7, 128.2, 128.8, 129.1, 129.4, 130.5, 139.7, 141.8,
154.9. Anal. Calcd for C18H14OTe2: C, 43.11; H, 2.81.
Found: C, 42.82; H, 3.06.
4.2.3. 1,1-Bis(phenyltelluro)-2-(4-nitrophenyl)-1-ethene
6c. Yield 0.404 g (72%). MS m/z (rel. int.) 557 (MCK4,
1.9), 353 (2.6), 207 (36.0), 77 (100.0). H NMR (80 MHz,
1
CDCl3) d 7.07–7.22 (m, 2H); 7.23–7.41 (m, 6H); 7.42 (s,
1H); 7.74–7.87 (m, 4H); 7.95–8.18 (m, 2H); 13C NMR
(20 MHz, CDCl3) d 93.0, 115.1, 118.1, 123.4, 128.1, 128.9,
129.2, 129.3, 129.8, 140.0, 140.6, 140.9, 146.0, 146.6. Anal.
Calcd for C20H15NO2Te2: C, 43.16; H, 2.72. Found: C,
43.16; H, 2.81.
4.2.4. 1,1-Bis(phenyltelluro)-1-pentene 6d. Yield 0.453 g
(94%). MS m/z (rel. int.) 479 (MCK3, 32.0), 207 (9.0), 145
(90.0), 77 (100.0). 1H NMR (80 MHz, CDCl3) d 0.85 (t, JZ

C. C. Silveira et al. / Tetrahedron 61 (2005) 7712–7718
7717
The dibutyltelluride was distilled off from the mixture using
a Kugelhohr apparatus (50 8C/0.1 mmHg) leaving the
products 12d–h as pure materials. Spectral data of 12a–h
are listed below.
4.3.7. 1,1-Bis(butyltelluro)-4,8-dimethyl-1,7-nonadiene
12g. Yield 0.472 g (90%). MS m/z (rel. int.) 506 (MCK3,
–CH3, 7.5), 451 (100.0), 313 (34.5), 183 (67.0), 57 (62.0).
1H NMR (200 MHz, CDCl3) d 0.92 (t, JZ7.0 Hz, 9H); 1.60
(s, 3H); 1.68 (s, 3H); 1.00–2.50 (m, 15H); 2.78 (t, JZ
7.5 Hz, 4H); 5.09 (t, JZ6.5 Hz, 1H); 6.73 (t, JZ6.9 Hz,
1H); 13C NMR (50 MHz, CDCl3) d 11.7, 13.5, 13.8, 17.6,
19.6, 25.2, 25.6, 32.8, 33.5, 33.9, 36.7, 46.4, 76.7, 124.6,
131.1, 153.5. Anal. Calcd C19H36Te2: C, 43.91; H, 6.98.
Found: C, 43.57; H, 6.81.
4.3.1. 1,1-Bis(butyltelluro)-2-phenyl-1-ethene 12a. Yield
0.357 g (75%). MS m/z (rel. int.) 474 (MCK2, 12.3), 102
(15.6), 57 (100.0). H NMR (200 MHz, CDCl3) d 0.86 (t,
1
JZ7.3 Hz, 3H); 0.94 (t, JZ7.3 Hz, 3H); 1.25–1.55 (m, 4H);
1.6–1.8 (m, 2H); 1.8–2.0 (m, 2H); 2.74 (t, JZ7.5 Hz, 2H);
2.92 (t, JZ7.5 Hz, 2H); 7.20–7.38 (m, 5H); 7.96 (s, 1H);
13C NMR (50 MHz, CDCl3) d 12.8, 13.4, 13.5, 15.6, 25.1,
25.2, 33.4, 33.6, 79.6, 127.4, 128.0, 128.1, 141.0, 149.7.
Anal. Calcd for C16H24Te2: C, 40.75; H, 5.13. Found: C,
41.01; H, 5.10.
4.3.8. 1,1-Bis(butyltelluro)-2-cyclohexanyl-ethene 12h.
Yield 0.159 g (34%). MS m/z (rel. int.) 466 (MCK2,
34.2), 95 (90.4), 41 (100.0). 1H NMR (200 MHz, CDCl3) d
0.91 (t, JZ7.0 Hz, 6H); 1.31–1.45 (m, 4H); 1.47–153 (m,
6H); 1.65–1.83 (m, 4H); 2.62 (t, JZ7.0 Hz, 4H); 2.75 (t, JZ
7.0 Hz, 4H); 13C NMR (50 MHz, CDCl3) d 13.5, 14.4, 25.2,
26.4, 28.6, 33.6, 41.5, 74.3, 161.1. Anal. Calcd C15H28Te2:
C, 38.86; H, 6.09. Found: C, 38.95; H, 6.15.
4.3.2. 1,1-Bis(butyltelluro)-2-(4-methylphenyl)-1-ethene
12b. Yield 0.343 g (70%). MS m/z (rel. int.) 488 (MCK2,
13.8), 115 (64.7), 57 (100.0). 1H NMR (200 MHz, CDCl3) d
0.86 (t, JZ7.2 Hz, 3H); 0.93 (t, JZ7.2 Hz, 3H); 1.22–1.52
(m, 4H); 1.63–1.78 (m, 2H); 1.80–1.95 (m, 2H); 2.31 (s,
3H); 2.74 (t, JZ7.4 Hz, 2H); 2.89 (t, JZ7.4 Hz, 2H); 7.20
(d, JZ7.9 Hz, 2H); 7.11 (d, JZ7.9 Hz, 2H); 7.95 (s, 1H);
13C NMR (50 MHz, CDCl3) d 12.5, 13.4, 15.5, 21.1, 24.9,
25.0, 33.2, 33.5, 78.6, 127.8, 128.5, 137.0, 137.9, 149.8.
Anal. Calcd C17H26Te2: C, 42.05; H, 5.40. Found: C, 42.27;
H, 5.27.
Acknowledgements
The authors acknowledge the financial support provided by
SCT-RS, FAPERGS, CNPq and CAPES.
4.3.3. 1,1-Bis(butyltelluro)-2-(4-chlorophenyl)-1-ethene
12c. Yield 0.321 g (63%). MS m/z (rel. int.) 508 (MCK2,
8.8), 136 (19.1), 57 (100.0). 1H NMR (200 MHz, CDCl3) d
0.86 (t, JZ7.1 Hz, 3H); 0.93 (t, JZ7.1 Hz, 3H); 1.22–1.53
(m, 4H); 1.63–1.78 (m, 2H); 1.80–1.96 (m, 2H); 2.74 (t, JZ
7.5 Hz, 2H); 2.90 (t, JZ7.5 Hz, 2H); 7.22–7.31 (m, 4H);
7.86 (s, 1H); 13C NMR (50 MHz, CDCl3) d 13.0, 13.3, 13.4,
15.8, 25.0, 25.1, 33.2, 33.5, 81.1, 128.1, 129.3, 133.0, 139.1,
147.7. Anal. Calcd for C16H23ClTe2: C, 37.98; H, 4.58.
Found: C, 38.78; H, 4.37.
References and notes
1. For reviews on preparation and reactivity of vinyl tellurides,
see: (a) Petragnani, N.; Stefani, H. A. Tetrahedron 2005, 61,
1613. (b) Vieira, M. L.; Zinn, F. K.; Comasseto, J. V. J. Braz.
Chem. Soc. 2001, 12, 586. (c) Barrientos-Astigarraga, R. E.;
Castelani, P.; Comasseto, J. V.; Formiga, H. B.; Silva, N. C.;
Sumida, C. Y.; Vieira, M. L. J. Organomet. Chem. 2001, 623,
43. (d) Comasseto, J. V.; Barrientos-Astigarraga, R. E.
Aldrichim. Acta 2000, 33, 66. (e) Comasseto, J. V.; Ling,
L. W.; Petragnani, N.; Stefani, H. A. Synthesis 1997, 373.
2. Petragnani, N. Best Synthetic Methods—Tellurium in Organic
Synthesis; Academic: , 1994.
4.3.4. 1,1-Bis(butyltelluro)-1-pentene 12d. Yield 0.385 g
(87%). MS m/z (rel. int.) 440 (MCK2, 8.3), 255 (9.1), 57
1
(100.0). H NMR (200 MHz, CDCl3) d 0.92 (t, JZ7.3 Hz,
3. (a) Huang, Y. Z.; Mo, X. S. Synlett 1998, 93. (b) Mo, X. S.;
Huang, Y. Z. Tetrahedron Lett. 1995, 36, 3539. (c) Dabdoub,
M. J.; Begnini, M. L.; Cassol, T. M.; Guerrero, P. G., Jr.;
Silveira, C. C. Tetrahedron Lett. 1995, 36, 7623. (d) Hiiro, T.;
Kambe, N.; Ogawa, A.; Miyoshi, N.; Murai, S.; Sonoda, N.
Angew. Chem., Int. Ed. Engl. 1987, 26, 1187. (e) Barros, S. M.;
Comasseto, J. V.; Berriel, J. N. Tetrahedron Lett. 1989, 30,
7353. (f) Barros, S. M.; Dabdoub, M. J.; Dabdoub, V. B.;
Comasseto, J. V. Organometallics 1989, 8, 1661. (g) Ogawa,
A.; Tsuboi, Y.; Obayashi, R.; Yokoyama, K.; Ryu, I.; Sonoda,
N. J. Org. Chem. 1994, 59, 1600. (h) Dabdoub, M. J.;
Dabdoub, V. B. Tetrahedron 1995, 51, 9839. (i) Dabdoub,
M. J.; Jacob, R. G.; Ferreira, J. T. B.; Dabdoub, V. B.;
Marques, F. A. Tetrahedron Lett. 1999, 40, 7159. (j) Dabdoub,
M. J.; Dabdoub, V. B.; Comasseto, J. V. Tetrahedron Lett.
1992, 33, 2261. (k) Dabdoub, M. J.; Dabdoub, V. B.; Guerrero,
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9H); 1.31–1.50 (m, 6H); 1.69–1.90 (m, 4H); 2.22 (q, JZ
7.1 Hz, 2H); 2.78 (t, JZ7.4 Hz, 4H); 6.72 (t, JZ6.9 Hz,
1H); 13C NMR (50 MHz, CDCl3) d 11.8, 13.5, 13.6, 13.7,
22.1, 25.2, 33.4, 33.9, 41.4, 75.9, 154.3. Anal. Calcd for
C13H26Te2: C, 35.69; H, 5.99. Found: C, 35.40; H, 5.77.
4.3.5. 1,1-Bis(butyltelluro)-1-hexene 12e.16b Yield 0.415 g
(91%). H NMR (200 MHz, CDCl3) d 0.88–0.95 (m, 9H);
1
1.34–1.50 (m, 8H); 1.69–1.85 (m, 4H); 2.25 (q, JZ7.0 Hz,
2H); 2.77 (2t, JZ7.3 Hz, 4H); 6.71 (t, JZ6.9 Hz, 1H); 13C
NMR (50 MHz, CDCl3) d 11.7, 13.4, 13.6, 13.9, 22.1, 25.1,
30.9, 33.3, 33.8, 39.0, 77.6, 154.4.
4.3.6. 1,1-Bis(butyltelluro)-1-octene 12f.16b Yield 0.445 g
(92%). H NMR (200 MHz, CDCl3) d 0.85–0.95 (m, 9H);
1
1.28–1.50 (m, 12H); 1.69–1.89 (m, 4H); 2.24 (q, JZ7.0 Hz,
2H); 2.77 (t, JZ7.2 Hz, 2H); 2.78 (t, JZ7.2 Hz, 2H); 6.71
(t, JZ6.9 Hz, 1H); 13C NMR (50 MHz, CDCl3) d 11.7, 13.4,
13.6, 14.0, 22.5, 25.1, 28.7, 28.8, 31.6, 33.3, 33.8, 39.3,
75.8, 154.5.
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