Hydroalumination of silylacetylenes: A novel and highly stereoselective synthesis of (E)-telluro(silyl)ketene acetals and their applications in Sonogashira cross-coupling reactions

Article abstract of DOI:10.1016/j.tetlet.2011.08.147

The hydroalumination of silylacetylenes with DIBAL-H followed by the addition of n-butyllithium generated in situ the (Z)-β-vinylorganosilane alanates intermediates, which were trapped with butyltellurenyl bromide (C ₄H₉TeBr), furnis

Full text of DOI:10.1016/j.tetlet.2011.08.147

Tetrahedron Letters 52 (2011) 6067–6071
Contents lists available at SciVerse ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Hydroalumination of silylacetylenes: a novel and highly stereoselective
synthesis of (E)-telluro(silyl)ketene acetals and their applications in
Sonogashira cross-coupling reactions
Cristiane Y. Kawasoko a, Carlos E.D. Nazario a, Amanda S. Santana a, Luiz H. Viana a, Gabriela R. Hurtado a,
Francisco A. Marques b, Gustavo Frensch b, Paulo R. de Oliveira c, Palimécio G. Guerrero Jr. c,
Diego B. Carvalho d, Adriano C.M. Baroni d,
⇑
a Departamento de Química, Universidade Federal do Mato Grosso do Sul, UFMS, Campo Grande, MS, Brazil
b Departamento de Química, Universidade Federal do Paraná UFPR, Curitiba, PR, Brazil
c Departamento de Química e Biologia, DAQBi, Universidade Tecnológica Federal do Paraná, UTFPR, Curitiba, PR, Brazil
d Departamento de Fármacia-Bioquímica, Universidade Federal do Mato Grosso do Sul, UFMS, Campo Grande, MS, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
The hydroalumination of silylacetylenes with DIBAL-H followed by the addition of n-butyllithium gener-
ated in situ the (Z)-b-vinylorganosilane alanates intermediates, which were trapped with butyltellurenyl
bromide (C4H9TeBr), furnishing exclusively the (E)-1-butyltelluro-1-tri(organyl)silyl-2-organyl-1-
alkenes in 45–70% yields. These telluro(silyl)ketene acetals were utilized as substrates in Sonogashira
cross-coupling Pd-catalyzed reactions, furnishing the (Z)-1,4-diorganyl-2-tri(organyl)silyl-1-buten-3-
ynes with total control of regio- and stereochemistry in 62–80% yield.
Received 9 August 2011
Accepted 24 August 2011
Available online 1 September 2011
Keywords:
Hydroalumination
Ó 2011 Elsevier Ltd. All rights reserved.
(Z)-b-Vinylorganosilane alanates
Sonogashira cross-coupling
Telluro(silyl)ketene acetals
(Z)-1,4-Diorganyl-2-tri(organyl)silyl-1-
buten-3-ynes
Over the past four decades, the syn-hydroalumination of terminal
alkynes with the commercially available di-(isobutyl)aluminum hy-
dride (DIBAL-H) as reducing agent, has been established as a highly
efficient and versatile methodology for the generation of (E)-viny-
lorganoaluminum intermediates following an anti-Markovinikov
mechanism.1 On the other hand, amazing results in the generation
of alana intermediates with opposite regiochemistry such as
chalcogene electrophiles, furnishing the 1,1-bis(organylchalco-
gene)-1-alkenes.
The pioneer study by Eich and co-workers8 described mechanis-
tically the coordination of a Lewis base to the empty 3p orbital of
the Al metal, permitting the total retention of configuration of the
Z-vinylaluminum generated by the stereoselective syn-addition of
DIBAL-H to silylacetylenes.
a
-vinylorganoaluminum were obtained via Ni-catalyzed hydroalu-
Recently, Hoveyda and co-workers9 reported the reduction of
silylacetylenes carried out with DIBAL-H in a solvent mixture of
hexane/THF (5:1), furnishing the cis-vinyl metals which were ap-
plied in Cu-catalyzed cross coupling, aiming at the stereoselective
total synthesis of the antifungal (À)-nyasol.
minationofterminalalkyneswithDIBAL-H.2 Thisvinylorganoalumi-
num can be applied as a soft nucleophile to form new carbon–carbon
bonds with high enantioselectivity in catalytic systems,3 transmeta-
lation processes4 and to prepare vinyl halides, normally used as a
substrate in cross-coupling reactions.5
However, to the best of our knowledge, methodologies to pre-
pare telluro(silyl)ketene acetals from Al/Te transmetalation and
their applications in cross-coupling reactions have not yet been
reported.
Investigations involving the hydroalumination of disubstituted
alkynes represented by selenoacetylenes6 and thioacetylenes7
with DIBAL-H and lithium di-(isobutyl)-n-butyl aluminate hydride
(Zweifel’s reagent), were carried out by our group. In these
processes, the b-organylchalcogene vinylorganoaluminum inter-
mediates were generated ‘in situ’ and then reacted with
The hydroalumination of silylacetylenes 1a–g with DIBAL-H in
hexanes/ethyl ether furnished stereoselectively the (Z)-b-vinylor-
ganosilane alanas 2a–g. Subsequently, we investigated the addi-
tion of n-BuLi to 2a–g at 0 °C to afford ‘in situ’ the novel ‘ate
complex’ (Z)-b-vinylorganosilane alanate intermediates 3a–g
which were then trapped with butyltellurenyl bromide (C4H9TeBr),
⇑
Corresponding author. Tel./fax: +55 67 3345 7365.
E-mail address: adriano.baroni@ufms.br (A.C.M. Baroni).
0040-4039/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2011.08.147

6068
C. Y. Kawasoko et al. / Tetrahedron Letters 52 (2011) 6067–6071
Table 1
Synthesis of (E)-telluro(silyl)ketene acetals15–18
Si(R1)3
Al
Si(R1)3
Al
Al
H
R
Si(R1)3
R
R
C4H9TeBr/LiCl
THF/hexane/0oC
n-C4H9Li
THF/0oC
Li
Si(R1)
R
TeC4H9
Hexanes/ethyl ether/r.t
magnetic stirring or sonication
C4H9
1a-g
(E)-4a-g
3a-g
2a-g
R = Alkyl, aryl, alkenyl, OCH2C6H5
R1 = (CH3)3, (CH3)2C6H5
Entry
1
Silylacetylene
Producta
Timeb (h)
4.5
Yieldc (%)
65
Si(CH3)3
C4H9
C4H9
Si(CH3)3
1a
TeC4H9
Si(CH3)3
4a
4b
C6H13
C6H13
C6H5
Si(CH3)3
Si(CH3)3
1b
2
3
4.5
4.5
65
70
TeC4H9
C6H5
Si(CH3)3
1c
TeC4H9
Si(CH3)3
TeC4H9
4c
Si(CH3)3
1d
4
5
4.5
6.0
45
50
4d
C6H5CH2OCH2
C6H5CH2OCH2
Si(CH3)3
Si(CH3)3
TeC4H9
1e
4e
Si(CH3)2C6H5
Si(CH3)2C6H5
C4H9
C4H9
C6H5
Si(CH3)2C6H5
1f
6
7
4.5
4.5
60
70
TeC4H9
4f
C6H5
Si(CH3)2C6H5
1g
4g
TeC4H9
a
Fully characterized by NMR (1H, 13C), microanalysis data.
Reaction conditions: 1a–d (1.0 mmol), DIBAL-H (1.5 mmol in hexane), ethyl ether (3.0 mL) at room temperature under magnetic stirring (2 h), n-BuLi (1.0 mmol)—
b
30 min. at 0 °C, C4H9TeBr/LiCl (2.0 mmol)—2 h at 0 °C; 1e (1.0 mmol), DIBAL-H (3.75 mmol in hexane), ethyl ether (4.5 mL) at room temperature under sonication (3.5 h), n-
BuLi (1.5 mmol)—30 min. at 0 °C, C4H9TeBr/LiCl (2.0 mmol)—2 h at 0 °C; 1f–g (1.0 mmol), DIBAL-H (1.5 mmol in hexane), ethyl ether (3.0 mL) at room temperature under
sonication (2 h), n-BuLi (1.0 mmol)—30 min. at 0 °C, C4H9TeBr/LiCl (2.0 mmol)—2 h at 0 °C.
c
Isolated yields after purification by chromatography using silica gel (230–400 mesh) using hexane (4a–d, f–g) and a mixture of ethyl acetate/hexane (0.5:9.5 v/v) as the
mobile phase for 4e.
Table 2
Cross-coupling reaction of 4b and 1-heptyne
C6H13
C6H13
Si(CH3)3
Si(CH3)3
C6H13
Si(CH3)3
TeC4H9
PdCl2/CuI/methanol
C5H11
+
H/(C2H5)3N
TeC4H9
4b
5a
6c
4b
C5H11
Entry
PdCl2(mol %)/CuI (mol %)
1-heptyne (equiv)
Time (h)
Rateb 4b:6c
1a
2
3
4
5
6
7
8
9
20/20
20/20
20/20
20/20
20/10
30/30
20/20
30/30
20/20
30/30
20/20
20/20
2.0
1.0
2.5
3.0
3.0
2.0
3.0
3.0
2.0
3.0
2.0
3.0
8
1:4
1:4
1:4
1:4
1:4
0:1
0:1
0:1
0:1
0:1
0:1
1:5
18
18
18
18
64
72
48
72
36
48
36
10
11
12
a
Reaction carried out as described in Ref. 12
Ratio determined by 1H NMR.
b

C. Y. Kawasoko et al. / Tetrahedron Letters 52 (2011) 6067–6071
6069
Table 3
furnishing exclusively the (E)-telluro(silyl)ketene acetals 4a–g (Ta-
ble 1). The addition of DIBAL-H to the triple bond of the silylacet-
ylenes using a mixture of hexane/ethyl ether as solvent, occurred
in a cis-fashion mechanism, transferring the organoaluminum moi-
ety to the same C-sp2 containing the trialkyl silyl group (Table 1).
We believe that the ethyl ether acts as a Lewis base8,9 playing an
important role in the total control of the stereochemistry in the cis-
hydroalumination of the silylacetylenes 1a–g. However, these
intermediates showed very low reactivity toward Al/Te transmeta-
lation with electrophiles such as butyltellurenyl bromide
(C4H9TeBr). So, the activation of the vinyl alanas type 2 was per-
formed by the reaction with n-BuLi producing the highly reactive
(Z)-b-vinylorganolsilane alanates 3a–g which were then reacted
with n-butyltellurenyl bromide leading to the (E)-tell-
uro(silyl)ketene acetals 4a–g in good yields (Table 1).
Cross-coupling reaction of 4b and 1-heptyne
C6H13
C6H13
Si(CH3)3
Si(CH3)3
C6H13
Si(CH3)3
TeC4H9
PdLnCl2/MI/methanol
+
C5H11
H/ Et3N
TeC4H9
5a
4b
6c
4b
) ) )
C5H11
L = (PPh3); n = 0, 2, 4
n = 0, PdCl2; n = 2, PdCl2(PPh3)2; n = 4, PdCl2(PPh3)4
M = Cu, Ag
Entry
PdLnCl2 (mol %)/MI (mol %)
Time (min)
Ratea 4b:6c
1
2
3
4
5
6
7
8
9
PdCl2(PPh3)2 (20 mol %)/CuI (30 mol %)
PdCl2(PPh3)2 (20 mol %)/CuI (30 mol %)
PdCl2(PPh3)2 (5 mol %)/CuI (10 mol %)
PdCl2 (30 mol %)/AgI (30 mol %)
PdCl2 (30 mol %)/AgI (30 mol %)
PdCl2 (30 mol %)/AgI (30 mol %)
PdCl2 (20 mol %)/AgI (20 mol %)
PdCl2 (20 mol %/CuI(20 mol %)
60
90
50
50
90
120
50
50
50
1:6
0:1
1:0
1:2
1:6
0:1
1:3
0:1
1:0
Among the methodologies applied to build new carbon–carbon
bonds in mild conditions, the Pd-catalyzed cross-coupling reac-
tions, described by Sonogashira and co-workers,10 have been inten-
sively explored.11 However, the Sonogashira reaction involving
telluro(silyl)ketene acetals as substrate has not been reported so
far.
Pd(PPh3)4 (5 mol %)/CuI (10 mol %)
a
Ratio determined by 1H NMR.
Table 4
Synthesis of (Z)-1,4-diorganyl-2-tri(organyl)silyl-1-buten-3-ynes19–21
R
Si(R1)3
R
Si(R1)3
PdCl2/CuI, methanol, r.t
H
Et3N,R2
TeC4H9
5a-e
) ) )
R2
(E)-4a-c, f-g
(Z)-6a-j
R1 = (CH3)3, (CH3)2C6H5
R2 = Alkyl, aryl, alkynyl, (CH3)2(OH)C, CH2OH
Entry
1
(E)-Telluro(silyl)keteneacetal
1-alkyne
Producta,b
Time (min)
50
Yieldc (%)
C4H9
C5H11
C4H9
H
Si(CH3)3
Si(CH3)3
5a
75
TeC4H9
4a
6a
C5H11
C4H9
C6H5
C4H9
Si(CH3)3
TeC4H9
H
Si(CH3)3
5b
2
90
73
4a
4b
6b
C6H5
C6H13
C5H11
C6H13
H
Si(CH3)3
TeC4H9
Si(CH3)3
5a
5c
3
4
5
50
80
62
75
6c
C5H11
C6H13
HO
C6H13
Si(CH3)3
TeC4H9
Si(CH3)3
H
120
60
4b
4b
6d
OH
C6H13
C6H13
Si(CH3)3
TeC4H9
Si(CH3)3
OH
H
H
5d
OH
6e
C6H13
C6H5
C6H13
Si(CH3)3
TeC4H9
Si(CH3)3
5b
6
90
75
4b
6f
C6H5
(continued on next page)

6070
C. Y. Kawasoko et al. / Tetrahedron Letters 52 (2011) 6067–6071
Table 4 (continued)
Entry
(E)-Telluro(silyl)keteneacetal
1-alkyne
Producta,b
Time (min)
60
Yieldc (%)
C H
6
C6H5
5
Si(CH )
3 3
Si(CH3)3
OH
H
7
8
70
TeC H
4
9
H
5d
4c
6g
OH
C H
6
C6H5
C6H5
5
Si(CH )
3 3
Si(CH3)3
5b
90
90
50
68
68
72
TeC H
4
9
6h
4c
4f
C6H5
C4H9
C6H13
C4H9
H
Si(CH3)2C6H5
TeC4H9
Si(CH3)2C6H5
5e
9
6i
C6H13
C6H5
C5H11
C6H5
H
Si(CH3)2C6H5
TeC4H9
Si(CH3)2C6H5
5a
10
4g
6j
C5H11
a
Fully characterized by NMR (1H, 13C), microanalysis data.
b
Reaction conditions: 4a–c,f–g (0.5 mmol), 5a–e (1.0 mmol), triethylamine (1.0 mmol) in methanol (5.0 mL) at room temperature, catalytic system: PdCl2 20 mmol%/CuI
20 mmol %.
c
Isolated yields after purification by chromatography using silica gel (230–400 mesh) in hexane (6a–c, f, h–i) or a mixture of ethyl acetate:hexane (1:9 v/v) as the mobile
phase (6d–e, g).
Therefore, we examined the protocol described in the litera-
ture12 to carry out the reaction of (E)-1-butyltelluro-1-tri(methyl)-
silyl-1-octene (1.0 equiv) 4b and 1-hepyne (2.0 equiv) in a catalytic
system containing PdCl2 (20 mol %), CuI (20 mol %) in methanol/
triethylamine (5.0 mL/0.3 mL), which furnished the (Z)-8-tri
(methyl)silyl-7-pentadecen-9-yne 6c.
R
Si(R1)3
R2
6
R
Si(R1)3
However, the reaction did not proceed to completion and an
appreciable amount of the starting material 4b was recovered in-
tact, as detected by NMR (Entry 1, Table 2).
In order to increase the yield of the process, several reaction
conditions were tested, and the relationship between PdCl2/CuI,
the amounts of 1-heptyne, and the reaction times needed to be
modified (Table 2, entries 6–11) in comparison with the literature
(Table 2, entry 1).12 However, the reaction time needed to obtain
the desired product 6c remained long in all conditions tested (from
36 to 72 h).
Within the context of exploring a novel, efficient, and general
methodology to prepare (Z)-1,4-diorganyl-2-tri(organyl)silyl-1-
but-en-3-ynes from Sonogashira-type cross coupling, we studied
the reaction of the (Z)-telluro(silyl)ketene acetals 4b (1.0 equiv)
and 1-heptyne (2.0 equiv) in a wide range of reaction conditions,
under sonication (Table 3).
The best result was obtained when the (E)-telluro(silyl)ketene
acetal 4b (1.0 equiv) reacted with 1-heptyne 5a (2.0 equiv) in the
presence of PdCl2 (20 mol %)/CuI (20 mol %) and methanol/triethyl-
amine as solvent under sonication (50 min), to give only the (Z)-
1,4-diorganyl-2-tri(methyl)-silyl-1-buten-3-ynes 6c, in 80% yield
(Entry 8, Table 3).
10 Pd Cl
reductive elimination
R
Si(R1)3
TeC4H9
Cl
PdCl2
4
R2
oxidation addition
trans/cis isomerization
Si(R1)3
R
Pd
Cl
Cl
9
R
Si(R1)3
Pd Cl
R2
7
Cl TeC4H9
transmetalation
R2
Cu
CuTeC4H9
8
H
N
TeC4H9
Next, we applied this improved reaction condition to perform
the cross-coupling reaction using the (E)-telluro(silyl)ketene ace-
tals 4a–f and 1-alkynes 5a–e, which were totally consumed after
50 to 120 min, affording the (Z)-1,4-diorganyl-2-(triorganyl)silyl-
1-buten-3-ynes 6a–j in good yields (Table 4).
The complete Sonogashira reaction mechanism using palla-
dium as a catalyst and copper as a cocatalyst in homogeneous
medium remains unknown.11a,13 Our cross-coupling mechanism
N
H
R2
H
R2
CuTeC4H9
R2 =Alkyl, aryl, alkynyl, (CH3)2(OH)C, CH2OH
R1 =(CH3), (CH3)2C6H5
Figure 1. A plausible Sonogashira-type cross-coupling reaction mechanism

C. Y. Kawasoko et al. / Tetrahedron Letters 52 (2011) 6067–6071
6071
14. (a) Bertus, P.; Fécourt, F.; Bauder, C.; Pale, P. New J. Chem. 2004, 28, 12; (b)
Létinois-Halbes, U.; Pale, P.; Berger, S. J. Org. Chem. 2005, 70, 9185; (c) Stambuli,
J. P.; Bühl, M.; Hartwig, J. F. J. Am. Chem. Soc. 2002, 124, 9346.
proposal, outlined in Figure1, involving the (E)-telluro(silyl)ketene
acetals and 1-alkynes is similar to that described in the litera-
ture.11a,11i Therefore, the PdCl2 must react with the vinyl
compound 4 in a fast oxidative addition, producing the initial
Pd-complex 7. The next step in the Pd-cycle would connect with
the cycle of the copper14 and subsequent Pd/Cu transmetalation
from the copper acetylide 8 (formed in the Cu-cycle) to give the
Pd-species 9 which after trans/cis isomerization and reductive
elimination will furnish the symmetrical and unsymmetrical (Z)-
1,4-diorganyl-2-tri(organyl)-silyl-1-buten-4-ynes 6, with regener-
ation of the catalyst (Fig. 1).
In summary, we describe herein the highly stereoselective syn-
thesis of (E)-telluro(silyl)ketene acetals 4a–g via Al/Te transmeta-
lation of the novel ‘ate complex’ (Z)-b-vinylorganosilane alanates,
which were generated by the hydroalumination of silylacetylene
with DIBAL-H followed by the addition of n-BuLi. The (E)-tell-
uro(silyl)ketene acetals were successfully applied in the Sonogash-
ira cross-coupling reaction with 1-alkynes, using sonication to
speed up the process, leading to the synthesis of the (Z)-1,4-dior-
ganyl-2-tri(organyl)silyl-1-buten-3-ynes. The mechanism of the
modified Sonogashira cross-coupling reaction is proposed.
15. Typical procedure for the synthesis of (E)-telluro(silyl)ketene acetals.
To a two-neck 50 mL flask under nitrogen atmosphere, containing a solution of
1-trimethysilyl-2-organyl ethyne and DIBAL-H in ethyl ether/hexane, the
mixture was stirred at 25 °C for the time and conditions shown in Table 1. The
disappearance of the starting material was confirmed by TLC using hexane as
eluent. The resulting solution was cooled to 0 °C and n-BuLi was transferred
and the reaction stirred for 30 min. Then, a solution of butyl tellurenylbromide/
lithium chloride [(C4H9TeBr/LiCl 2.0 mmol], prepared separately by the
addition of bromine (0.070 g; 1.0 mmol) in hexane (5 mL) to a solution of
dibutyl ditelluride22 (0.368 g; 1.0 mmol) in THF (10 mL) cooled at 0 °C. Next,
dry lithium chloride (0.084 g; 2.0 mmol) was added and the mixture stirred for
10 min. Then, the solution of butyltellurenyl-bromide/lithium chloride was
added dropwise at 0 °C with a syringe to the (Z)-b-vinylorganolsilane alanates
3a–g derivatives. The stirring was continued for an additional time shown in
Table 1, and the mixture was transferred to an Erlenmeyer flask (500 mL) and
diluted with ethyl acetate (20 mL), water (50 mL) and 95% ethanol (20 mL).
Butyl bromide (1.0 mL) and finally NaBH4 (until the mixture turned pale
yellow) were added to transform dibutyl ditelluride to the corresponding
telluride, which is more easily removed by distillation. After this treatment, the
crude product was extracted with ethyl acetate (3 Â 20 mL) and washed with
brine (4 Â 15 mL). The organic phase was dried over anhydrous MgSO4, and the
solvent evaporated. After filtration through Celite using hexane as eluent, the
product was concentrated under vacuum. Dibutyl telluride was removed by
distillation from the crude product using
a Kugelrohr apparatus (80 °C/
0.01 mm Hg). Flash column chromatography (using silica gel 230–400 mesh
and the appropriate mobile phase as shown in Table 1) of the residue furnished
the (E)-telluro(silyl)ketene acetals as a yellow oil.
Acknowledgments
16. (E)-1-Butyltelluro-1-trimethylsilyl-1-octene 4b. Yield (65%), IR (neat, cmÀ1):
2954, 1573, 1377, 1245, 690. 1H NMR (300 MHz, in CDCl3) 0.21 (s, 9 H); 0.86–
0.94 (m, 6H); 1.27-1.42 (m, 10H); 1.73 (quint., J = 7.5 Hz, 2H); 2.18 (q,
J = 7.5 Hz, 2H); 2.69 (t, J = 7.5 Hz, 2H); 6.81 (t, J = 7.5 Hz, 1H). 13C NMR (75 MHz,
in CDCl3) 1.12; 7.17; 7.20; 13.42; 14.01; 22.57; 25.17; 28.87; 29.53; 31.71;
33.43; 35.94; 114.66; 156.76. Anal Calcd for C15H32SiTe: C, 48.91; H, 8.69;
Found: C, 48.84; H 8.80.
This article was financially supported by FUNDECT-MS, PROPP-
UFMS, CNPq, and CAPES. The authors thank Dr. Janet W. Reid (JWR
Associates) for assistance in revising the English text.
References and notes
17. (E)-1-Butyltelluro-1-trimethylsilyl-2-phenyl ethene 4c. Yield (70%), IR (neat,
cmÀ1) 3054, 3020, 2954, 2925, 1687, 1486, 1245, 835. 1H NMR (300 MHz, in
CDCl3) 0.21 (s, 9H); 1.10 (t, J = 7.5 Hz, 2H); 1.58 (sext., J = 7.5 Hz, 2H); 1.99
(quint., J = 7.5 Hz, 2H); 3.01 (t, J = 7.5 Hz, 2 H); 7.33–7.47 (m, 5H), 8.03 (s, 1H).
13C NMR (75 MHz, in CDCl3) 1.12; 7.15; 8.28; 13.45; 25.16; 33.29; 123.57,
127.16; 127.70; 127.79; 127.82; 127.85; 127.88; 151.47. Anal Calcd for
1. (a) Eisch, J. J. In Comprehensive Organic Synthesis; Trost, B. M., Fleiming, I.,
Schreiber, S. L., Eds.; Vol 8; Pergamom: Oxford, U.K, 1991; p 773; (b) Zweifel,
G.; Miller, J. A. Org. React. 1984, 32, 375; (c) Zweifel, G. In Aspects of Mechanism
and Organometallic Chemistry; Brewster, J. H., Ed.; Plenum Press: New York,
1978; p p 229; (d) Zweifel, G. In Comprehensive Organic Synthesis; Barton, D. H.
R., Ollis, W. D., Eds.; Pergamon: Oxford, U.K, 1979; p 1013; (e) Winterfeldt, E.
Synthesis 1975, 10, 617; (f) Negishi, E. Organometallics in Organic Synthesis;
Wiley: New York, 1980; (g) Uhl, W. Coord. Chem. Rev. 2008, 252, 1540; (h) Uhl,
W.; Er, E.; Hepp, A.; Kosters, J.; Grunenberg, J. Organometallics 2008, 27, 3346;
(i) Zweifel, G.; Whiney, C. C. J. Am. Chem. Soc. 1967, 89, 2753; (j) Uhl, W.; Er, E.;
Hepp, A.; Kosters, J.; Layh, M.; Rohling, M.; Vinogradov, A.; Wurthwein, E.-U.;
Ghavtadze, N. Eur. J. Inorg. Chem. 2009, 3307.
C
15H14SiTe: C, 49.99; H 6.66; Found C, 48.82; H 6.91.
18. (E)-1-Butytelluro-1-dimethyphenylsilyl-1-hexene 4f. Yield (60%),%), IR (neat,
cmÀ1 3064, 2954, 2957, 2158, 1591, 1472, 1247, 813, 698. 1H NMR
)
(300 MHz, in CDCl3) 0.49 (s, 9H); 0.80 (t, J = 7.5 Hz, 3H); 0.89 (t, J = 7.5 Hz,
3H); 1.13–1.38 (m, 6H); 1.69 (quint., J = 7.5 Hz, 2H); 2.04 (q, J = 7.5 Hz, 2H);
2.63 (t, J = 7.5 Hz, 2H); 6.89 (t, J = 7.5 Hz, 1H); 7.32–7.57 (m, 5H). 13C NMR
(75 MHz, in CDCl3) 0.70; 8.97; 13.45; 25.17; 33.14; 121.6; 127.23; 127.45;
127.61; 127.76; 127.94; 129.06; 130.1; 130.9; 131.1; 132.5; 133.98; 139.55;
141.47; 152.07. Anal Calcd for C18H30SiTe: C, 53.73, H 7.46; Found C, 53.55; H
7.54.
2. Gao, F.; Hoveyda, A. H. J. Am. Chem. Soc. 2010, 132, 10961.
3. (a) Lipshutz, B. H.; Bullow, G.; Lowe, R. F.; Steven, K. L. Tetrahedron 1996, 52,
7265; (b) Langille, N. F.; Jaminson, T. F. Org. Lett. 2006, 8, 3761; (c) Ziegler, F. E.;
Mikami, K. Tetrahedron Lett. 1984, 25, 131; (d) Sato, F.; Kodama, H.; Sato, M. J.
Organomet. Chem. 1978, 157, C30.
19. Typical procedure for the synthesis of (Z)-1,4-diorganyl-2-tri(organyl)silyl-1-
buten-3-ynes.
To
a two-neck flask under nitrogen atmosphere and magnetic stirring
containing PdCl2 (0.177; 0.1 mmol) and CuI (0.019 g; 0.1 mol) in methanol
(5.0 mL) was added the (E)-telluro(silyl)ketene acetal 4 (0.5 mmol) and the
solution stirred for 45 min. at 25 °C. Next, the 1-alkyne (1.0 mmol) and
triethylamine (0.6 mL; 1.0 mmol) were transferred via syringe, and the
reaction mixture stirred under sonication using an ultrasonic cleaner
(Unique Ultrasonic Cleaner–USC800A) for the time shown in Table 4 at room
temperature. Then, the crude product was extracted with hexanes (4 Â 20 mL)
and washed with brine (5 Â 15 mL), the organic phase dried under MgSO4, the
solvent evaporated and the product concentrated under vacuum. Finally, the
product was purified by flash chromatography (using silica gel 230–400 mesh
and the appropriate mobile phase as shown in Table 4) furnishing the (Z)-1,4-
diorganyl-2-tri(organyl)silyl-1-buten-3-ynes as a yellow oil.
4. (a) Dabdoub, M. J.; Dabdoub, V. B.; Cassol, T. M.; Barbosa, S. L. Tetrahedron Lett.
1996, 37, 831; (b) Dabdoub, M. J.; Cassol, T. M. Tetrahedron 1995, 51, 12982.
5. Liu, X.; Henderson, J. A.; Sasaki, T.; Kishi, Y. J. Am. Chem. Soc. 2009, 131, 16678.
6. Guerrero, P. G., Jr.; Dabdoub, M. J.; Baroni, A. C. M. Tetrahedron Lett. 2008, 49,
3872.
7. (a) Guerrero, P. G., Jr.; Dabdoub, M. J.; Marques, F. A.; Wosch, C. L.; Baroni, A. C.
M.; Ferreira, A. G. Synth. Commun. 2008, 38, 4379; (b) Dabdoub, M. J.; Guerrero,
P. G., Jr. Tetrahedron Lett. 2001, 42, 7167.
8. (a) Eisch, J. J.; Foxton, M. W. J. Org. Chem. 1971, 36, 3520; (b) Eisch, J. J.; Rhee, S.-
G. J. Am. Chem. Soc. 1975, 97, 4673.
9. Akiyama, K.; Gao, F.; Hoveyda, A. H. Angew. Chem., Int. Ed. 2010, 49, 419.
10. Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett. 1975, 16, 4467.
20. (Z)-1-hexyl-4-pentyl-2-trimethylsilyl-1-buten-3-yne 6a. Yield (75%). IR (neat,
cmÀ1) 2956, 2927, 2856, 2358, 2341, 1247, 838. 1H NMR (300 MHz, in CDCl3)
0.20 (s, 9H); 0.86–0.92 (m, 7H); 1.28–1.55 (m, 13H); 2.15 (q, J = 7.7 Hz, 2H);
2.31 (t, J = 7.7 Hz, 2H); 6.55 (t, J = 7.7 Hz, 1H). 13C NMR (75 MHz, in CDCl3) 0.03;
14.05; 19.55; 22.23; 22.59; 28.87; 29.56; 31.16; 31.74; 32.35; 83.53; 90.30;
109.78; 153.16. Anal Calcd For C16H30Si: C, 76.67, H 11.98; Found C, 76.61; H
10.89.
11. For
a recent review on Sonogashira cross-coupling reactions, see: (a)
Chinchilla, R.; Nájera, C. Chem. Rev. 2007, 107, 874. and references cited
therein; (b) Sing, V.; Ratti, N.; Kaur, S. J. Mol. Catal. A. 2011, 334, 13; (c) Posset,
T.; Guenther, J.; Pope, J.; Oeser, T.; Blumel, L. Chem. Commun. 2011, 47, 2059;
(d) Cao, J.; Yang, X.; Hua, X.; Deng, Y.; Lai, G. Org. Lett. 2011, 13, 478; (e) Parra,
J.; Mercader, J. V.; Agulló, C.; Abad-Fuentes, A.; Abad-Somovilla, A. Tetrahedron
2011, 67, 624; (f) Jordan, L. M.; Boyle, P. D.; Sargent, A. L.; Allen, W. E. J. Org.
Chem. 2010, 75, 8450; (g) Beaumont, S. K.; Kyriakou, G.; Lambert, R. M. J. Am.
Chem. Soc. 2010, 132, 12246; (h) Barmaz, D.; Proust, V.; Hu, X. J. Am. Chem. Soc.
2009, 131, 12078; (i) Kawaguchi, S.; Srivastava, P.; Engman, L. Tetrahedron Lett.
2011, 52, 4120; (j) Nazario, C. E. D.; Santana, A. S.; Kawasoko, C. Y.; Carollo, C.
A.; Hurtado, G. R.; Viana, L. H.; Barbosa, S. L.; Guerrero, P. G., Jr.; Marques, F. A.;
Dabdoub, V. B.; Dabdoub, M. J.; Baroni, A. C. M. Tetrahedron Lett. 2011, 52, 4177.
12. Zeni, G.; Comasseto, J. V. Tetrahedron Lett. 1999, 40, 4619.
21. (Z)-4-trimethylsilyl-undec-3-en-2-yn-1-ol 6d. Yield (62%). IR (neat, cmÀ1) 3348,
2954, 2925, 2856, 2198, 1249, 840. 1H NMR (300 MHz, in CDCl3) 0.21 (s, 9H);
0.88 (t, J = 7.5 Hz, 3H); 1.28–1.38 (m, 8H); 1.64 (s, 1H); 2.18 (q, J = 7.5 Hz, 2H);
4.39 (s, 2H); 6.65 (t, J = 7.5 Hz, 1H). 13C NMR (75 MHz, in CDCl3) 0.17; 13.99;
22.54; 28.96; 29.35; 31.68; 32.50; 51.79; 87.22; 89.09; 108.77; 155.42. Anal
Calcd for C14H25SiO: C, 70.76, H 10.54; Found C, 70.65; H 10.34.
22. (a) Cava, M.; Engman, L. Synth. Commun. 1982, 12, 163; (b) de Araujo, M. A.;
Raminelli, C.; Comasseto, J. V. J. Braz. Chem. Soc. 2004, 15, 358.
13. (a) Choudary, B. M.; Madhi, S.; Kantam, M. L.; Sreedhar, B.; Iwasawa, Y. J. Am.
Chem. Soc. 2004, 126, 2292; (b) Posset, T.; Bümel, J. J. Am. Chem. Soc. 2006, 128,
8394.