One-pot synthesis of mixed (Z)-1,2-bis(organylchalcogene)-1-alkenes precursors of the novel β-organylthio vinyllithium intermediates

Article abstract of DOI:10.1016/j.tetlet.2010.07.112

One-pot hydrochalcogenation of 1-phenylthioacetylenes using organylselenolate and organyltellurolate anions generated by the insertions of selenium and tellurium in n-organyl lithium produced (Z)-1,2- bis(organylchalcogene)-1-alkenes. The chemical reactiv

Full text of DOI:10.1016/j.tetlet.2010.07.112

Tetrahedron Letters 51 (2010) 5141–5145
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One-pot synthesis of mixed (Z)-1,2-bis(organylchalcogene)-1-alkenes
precursors of the novel b-organylthio vinyllithium intermediates
a
a
b
c
Miguel J. Dabdoub a, , Vânia B. Dabdoub , Marco A. Pereira , Adriano C. M. Baroni , Francisco A. Marques ,
*
Paulo R. de Oliveira d, Palimécio G. Guerrero Jr. d,
*
a Laboratório de Compostos Organocalcogênios, Universidade de São Paulo, Ribeirao Preto, SP, Brazil
b Departamento de Farmácia-Bioquímica, Universidade Federal do Mato Grosso do Sul, UFMS, Campo Grande, MS, Brazil
c Departamento de Química, Universidade Federal do Paraná, UFPR, Curitiba, PR, Brazil
d Laboratório de Síntese Orgânica e Produtos Naturais, Departamento de Química e Biologia, Universidade Tecnológica Federal do Paraná, UTFPR, Curitiba, PR, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
One-pot hydrochalcogenation of 1-phenylthioacetylenes using organylselenolate and organyltellurolate
anions generated by the insertions of selenium and tellurium in n-organyl lithium produced (Z)-1,2-
bis(organylchalcogene)-1-alkenes. The chemical reactivity of these mixed 1,2-bis(organylchalcogene)-
1-alkenes was studied by Te/Li and Se/Li stereoretentive exchanges carried out with n-butyl lithium,
furnishing the new intermediate species (Z)-b-organylthio vinyllithium anions, which were trapped with
aldehydes, to give the (Z)-3-hydroxy vinyl thioethers with total control of the regio- and stereochemistry.
Ó 2010 Elsevier Ltd. All rights reserved.
Received 1 July 2010
Accepted 20 July 2010
Available online 25 July 2010
Keywords:
Hydrochalcogenation
Transmetallation
Thioacetylenes
b-Organylthio vinyllithium
Stereocontrolled methodologies to prepare vinyl organylchalc-
ogenide compounds and their applications in the construction of
new carbon–carbon bonds via organometallic intermediates have
been developed with the highest priority.1 The hydrotelluration de-
scribed by Buzilova and co-workers2 stimulated a wide range of
studies leading to the synthesis of (Z)-vinyl tellurides by addition
of organyltellurolate anions to terminal and disubstituted alkynes
containing Michael acceptor groups.1f,3 The chemoselective reac-
tions of sodium tellurolate,4 selenolate,5 and thiolate6 anions occur
in conjugated butadyine systems with total control of regio- and ste-
reochemistry, furnishing the (Z)-1-organylchalcogene-1-buten-3-
ynes. Moreover, (E)-vinyl organochalcogenides were obtained by
the hydrozirconation of terminal and substituted alkynes using
bis(cyclopentadienyl) zirconium (IV) chloride hydride as a reducing
agent and subsequent Zr/Te7, Zr/Se,8 and Zr/S9 exchanges. Recently,
our group reported the synthesis of (E)-vinylsulfides by the hydroa-
lumination of thioacetylenes with lithium di(isobutyl)-n-butyl hy-
dride, followed by acid hydrolysis.10
On the other hand, (Z)-1,2-bis(organylchalcogene)-1-alkenes
were obtained by the hydrochalcogenation of thioacetylenes using
the organyltellurolate (RTeÀ) and organylselenolate (RSeÀ) anions
generated ‘in situ’ by the reduction of diorganyl ditelluride and dior-
ganyl diselenide with sodium borohydride.15 However, these dior-
ganyl dichalcogenides are known to produce neuropathy to the
central nervous system, teratogenic effects, and severe damage to
the liver and kidneys.16 Based on these facts and regarding the appli-
cations of (Z)-1,2-bis(organylchalcogene)-1-alkenes to the total
synthesis of natural products17 and functionalized alkynyl tellu-
rides, which have shown an interesting antidepressive action.18
We describe, herein, the one-pot hydrochalcogenation of 1-phenyl-
thioacetylenes 1a–g in THF/water, using the appropriated chalco-
gene nucleophilic species,19 generated ‘in situ’ by the insertion of
elemental tellurium19a or selenium19b in organyl lithium, avoiding
the preliminary preparation and use of volatile, air-sensitive, odor-
ous, and highly toxic diorganyl ditelluride and diorganyl disele-
nide.16 The addition of (RSeÀLi+) or (RTeÀLi+) anions to
thioacetylenes 1a–g occurred at the b-position relative to the phen-
ylthio group via the vinyl intermediate type 2 furnishing the mixed
(Z)-1,2-bis(organylchalcogene)-1-alkenes 3a–m in good yields
(Table 1).
Several methods to synthesize 1,1-bis(organylchalcogene)-1-al-
kenes such as telluroketene acetals,11 telluro(seleno)ketene ace-
tals,11a,12 telluro(thio)ketene acetals,13 and seleno(thio)ketene
acetals14 which could easily lead to the synthesis of trisubstituted
olefins containing two heteroatoms attached in the same C-sp2 posi-
tion have been developed.
As a representative example of this protocol, we performed the
hydrotelluration of 1-phenylthio-1-hexyne 1b (1.5 equiv) with the
lithium butyltellurolate anion [(C4H9TeLi),19a 1.5 equiv, generated
‘in situ’ by insertion of tellurium (1.5 equiv) in n-BuLi (1.5 equiv)]
in THF (6.0 mL) followed by the addition of water (4.0 mL) and
* Corresponding authors.
E-mail address: pali@utfpr.edu.br (P.G. Guerrero Jr.).
0040-4039/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2010.07.112

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M. J. Dabdoub et al. / Tetrahedron Letters 51 (2010) 5141–5145
Table 1
Synthesis of (Z)-1,2-bis(organylchalcogene)-1-alkenes
δ
RY
SC6H5
R1
SC6H5
H
RY
SC6H5
RLi
Yo
1a-g
RYLi
THF/0oC
δ
H2O/reflux
R1
R1
H
OH
Y = Te, Se
(Z)-3a-m
2
R = C6H5, C4H9
R1 = H, alkyl, aryl, alkenyl, -OCH3
64-80%
Entry
1
Thioacetylene
Nucleophile
Producta
Time (h)
1.5
Yieldb (%)
80
H
SC6H5
TeC4H9
TeC4H9
C6H5S
1a
C4H9TeLi
C4H9TeLi
3a
C4H9
C6H5S
C6H5S
SC6H5
SC6H5
1b
1c
2
3
2.5
2.5
76
73
C4H9
3b
3c
C7H15
TeC4H9
C4H9TeLi
C7H15
C6H5
C6H5S
SC6H5
TeC4H9
1d
4
5
C4H9TeLi
C4H9TeLi
1.5
1.5
80
75
C6H5
3d
3e
CH3O
C6H5S
C6H5S
TeC4H9
SC6H5
OCH3
TeC4H9
1e
SC6H5
1f
6
7
C4H9TeLi
C6H5TeLi
2.0
3.5
73
75
3f
C4H9
C6H5
C4H9
C6H5S
C6H5S
TeC6H5
SC6H5
SC6H5
1b
1d
C4H9
3g
TeC6H5
8
9
C6H5TeLi
C6H5SeLi
C6H5SeLi
3.0
4.0
4.0
73
78
64
C6H5
3h
3i
C6H5S
C6H5S
SC6H5
SC6H5
SeC6H5
1b
1g
1d
C4H9
C10H21
SeC6H5
10
C10H21
SeC6H5
3j
C6H5
C6H5S
SC6H5
11
12
C6H5SeLi
C6H5SeLi
3.5
4.0
73
70
C6H5
3k
3l
CH3O
C6H5S
C6H5S
SeC6H5
SC6H5
SC6H5
OCH3
SeC6H5
1e
13
C6H5SeLi
4.0
68
1f
3m
a
Fully characterized by NMR (1H, 13C, gNOESY), MS, microanalysis data.
Isolated yields after purification by chromatography using silica gel (230–400 mesh) and hexane as the mobile phase in all cases.
b

M. J. Dabdoub et al. / Tetrahedron Letters 51 (2010) 5141–5145
5143
Table 2
Synthesis of (Z)-3-hydroxy vinyl thioethers
HO
1) R2CHO
SC6H5
R1Y
R
Li
SC6H5
SC6H5
H
THF/-78oC
n-C4H9Li
R2
THF/-78oC
H
2) HCl (0.1M)
r.t.
R
H
R
(Z)-5a-d
4
50-67%
R = Aryl, alkyl, Y = Te. R = Aryl, Y = Se
R1 = C4H9, Y = Te. R 1 = C6H5, Y = Se
R
2 = Aryl, Alkyl
Entry
1
(Z)-1,2-Bis(organylchalcogene)
Electrophile
C6H5CHO
Producta
Yieldb (%)
OH
C6H5S
TeC4H9
C4H9
C6H5S
C6H5
64
3b
3b
3b
C4H9
OH
5a
C6H5S
TeC4H9
C4H9
C6H5S
2
3
4
5
6
7
C4H9CHO
C5H11CHO
C6H5CHO
C6H5CHO
C6H5CHO
C4H9CHO
C4H9
65
67
55
63
53
60
C4H9
OH
5b
5c
5d
C6H5S
TeC4H9
C4H9
C6H5S
C6H5S
C6H5S
C6H5S
C6H5S
C5H11
C4H9
OH
C6H5S
TeC4H9
C6H5
C6H5
3d
C6H5
OH
C6H5S
TeC6H5
C4H9
C6H5
3g
3h
3g
3g
C4H9
OH
5a
5d
5b
C6H5S
C6H5S
C6H5S
TeC6H5
C6H5
C6H5
C6H5
OH
TeC6H5
C4H9
C4H9
C4H9
OH
TeC6H5
C6H5S
C5H11
C4H9
8
9
C5H11CHO
C4H9CHO
58
—
C4H9
5c
C6H5S
C6H5S
SeC6H5
C4H9
No reaction
3i
OH
SeC6H5
C6H5
C6H5S
C6H5
C6H5
10
11
C6H5CHO
C6H5CHO
50
—
3k
5d
C6H5S
SeC6H5
No reaction
OCH3
3l
a
Fully characterized by NMR (1H, 13C), MS, microanalysis data.
Isolated yields after purification by chromatography using silica gel (230–400 mesh) and a mixture of ethyl acetate/hexane (2:8 v:v) as the mobile phase in all cases.
b

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M. J. Dabdoub et al. / Tetrahedron Letters 51 (2010) 5141–5145
subsequent reflux which furnished (Z)-1-phenylthio-2-butyltell-
uro-1-hexene 3b in 76% yield (entry 2, Table 1). The regio- and ste-
reochemistry of the mixed (Z)-1,2-bis(organylchalcogene)-1-
alkenes 3a–m were determined by NMR experiments. The vinylic
hydrogen multiplicity of the alkylsubstituted olefins 3b and 3i ob-
served in the 1H NMR (400 MHz) spectra was detected as a singlet
in 6.65 ppm and 6.61 ppm, respectively. The gNOESY experiments
of 3b and 3i in the 1H NMR showed an enhancement of the allylic
hydrogens’ signals when the vinylic hydrogens were irradiated. No
correlations were observed involving the vinylic hydrogens and
the hydrogens from the butyltelluro group for 3b and CH (aromatic)
attached to the selenium atom for 3i. Therefore, the NOE experi-
ments confirmed that the organylchalcogenes groups are situated
between them in a cis relationship. Considering the Z-configuration
of the 1,2-bis(organylchalcogene)-1-alkenes 3a–m, we believe that
the mechanism involved in the hydrochalcogenation of thioacetyl-
enes is similar to that observed for the hydrochalcogenation of acti-
vated acetylenes.4b,6c,20 The addition of the RTeÀ or RSeÀ anions at
the thioacetylene triple bond occurs in synchrony with the genera-
tion of the incipient carbanion intermediate onto C-sp2 attached to
phenylthio group 2, which promptly abstracts the hydrogen of the
water in an anti fashion mechanism (Table 1).
Acknowledgments
The authors thank the CNPq, CAPES, and Fundação Araucária for
financial support, Dr. Janet W. Reid (JWR Associates) for assistance
in revising the manuscript, and Professor Andersson Barisson UFPR
(Federal University of Paraná) for NMR facilities.
Supplementary data
Supplementary data (the detailed experimental procedure, char-
acterization data for all new compounds and respective copies of 1H
NMR, 13C NMR, and mass spectra) associated with this article can
be found, in the online version, at doi:10.1016/j.tetlet.2010.07.112.
References and notes
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tion of (Z)-b-organylthio vinyllithium 4 through the reaction of
(Z)-1,2-bis(organylchalcogene)-1-alkenes
3 (1.5 equiv) in THF
(10 mL) with n-BuLi (1.5 equiv) at À78 °C. The anions generated
were then reacted with aldehydes (1.5 equiv), furnishing the (Z)-
3-hydroxy vinyl thioethers 5a–d in moderate to good yields (Table
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n-BuLi. Reacting the (Z)-1-phenylseleno-1-phenyl-2-phenylthio
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group must stabilize the b-phenylthio vinyllithium anion by the
resonance effect. However, the reaction of compounds 3i and 3l
with n-BuLi failed, and the starting materials were recovered in-
tact. This demonstrated that the Se/Li exchange is less efficient
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to 1,2-bis(organylchalcogene)-1-alkenes 3, confirming our preli-
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M. J. Dabdoub et al. / Tetrahedron Letters 51 (2010) 5141–5145
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