Marciniec et al.
TABLE 5. Results of Catalytic Transformation of 3 with
Iodobenzene via Hiyama Coupling Catalyzed by IVa
and [RuCl2(PCy3)(IMesH2)(dCHPh)] (III). The ruthenium and
palladium complexes, [RuH(Cl)(CO)(PCy3)2] (I)11a and [Pd2-
(dba)3] (IV),11b were prepared according to the literature
procedure.
Catalytic Examinations of Silylative Coupling Reac-
tion. In a typical catalytic test, the ruthenium catalyst I (1
mol %) was dissolved in a toluene and placed in a glass ampule
under argon. Then the reagents and decane or dodecane as
internal standard (5 vol % all components) were added (usually
used at the molar ratio [Ru]:[ViSi]:[olefin] ) 0.01:1:1(2 or 3)).
After that, the ampule was heated at 105-110 °C for 20 h. In
the catalytic test with vinyltrimethylsilane, the sealed glass
ampule was heated at 80 °C for the same time.
molar
ratio
conv of
selectivity (%)
time iodobenzene
cross-linking
of byproducts
PhI/ViSi (h)
(%)
E
Z
1:1.2b
16
70
>99
trace middle
(dense solution)
1:1.2
5
12
93
91
>99
>99
1:1.25c
trace trace
a Reaction conditions: [Pd2(dba)3]:[Si]:[TBAF] ) 0.03:1:1.2; T
) 30°C; Ar (open system); THF 0.6M. b [Pd2(dba)3]:[Si] ) 0.02:1.
c THF 0.25 M.
Catalytic Examinations of Hiyama Coupling Reac-
tion. In a typical catalytic test, the reagents and decane or
dodecane as internal standard (5 vol % all components) were
dissolved in a tetrahydrofurane and placed in a glass ampule
under argon (usually used at the molar ratio [ViSi]:[PhJ]:
[TBAF] ) 1:0.9:1.1). Then the palladium catalyst IV (5 mol
%) was added and the ampule was heated from 30 to 60 °C
for 24 h.
Catalytic Examinations of Silylative Coupling and
Hiyama Coupling. Tandem Reaction. In typical catalytic
test the (E)-9-[2-(silyl)ethenyl)]-9H-carbazole is not isolated
after silylative coupling reaction (amount calculated from GC
analyses). Then, the next reagents and decane as internal
standard (5 vol % all components) were dissolved in an
appropriate amount of THF and placed in a glass ampule
under argon (usually used in the molar ratio [ViSi]:[PhJ]:
[TBAF] ) 0.8:1:1.2). After that, the palladium catalyst IV (3
mol %) was added and the ampule was heated in 30 °C for 24
h.
During catalysis the conversion of the substrates was
calculated using the internal standard method. The composi-
tion of the reaction mixture was analyzed by GC and GC-
MS.
Syntheses of Silyl-carbazole Derivative Compounds.
The syntheses were performed under argon using [RuH(Cl)-
(CO)(PCy3)2] (I) as the catalyst and dry, deoxygenated reagents
and solvent. In all cases the final mixtures were isolated. The
details are presented below.
give product 4 without biphenyl formation. Moreover, the
reduction of the catalyst amount to 2 mol % requires more
solvent and longer reaction time (12 h). The above
presented preliminary research results of the Hiyama
reaction with the use of silyl derivative of carbazole are
the subject of detailed study of its application to obtain
new organic compounds via the tandem silylative coupling-
Hiyama coupling methodology.
Conclusions
In this paper a new effective synthesis of (E)-9-[2-
(silyl)ethenyl)]-9H-carbazole has been demonstrated via
a highly stereoselective silylative coupling reaction of
vinylcarbazole with vinyltrisubstituted silanes catalyzed
by [RuH(Cl)(CO)(PCy3)2] (I). The X-ray crystal structures
of trimethylsilyl- (1) and dimethylphenylsilyl- (2) vinyl
carbazoles as the first structural analysis of N-vinylcar-
bazole derivatives have been solved. The Hiyama cou-
pling reaction of the synthesized (E)-9-[2-(triethoxysilyl)-
ethenyl]-9H-carbazole (1) with iodobenzene gives (E)-9-
[2-(phenyl)ethenyl]-9H-carbazole (4) with high stereo-
selectivity. Finally, a tandem silylative coupling-Hiyama
coupling reaction performed under mild conditions makes
it possible to obtain 4 with high efficiency.
(E)-9-[2-(Trimethylsilyl)ethenyl]-9H-carbazole (1). [Ru-
H(Cl)(CO)(PCy3)2] (I) (49 mg, 0.068 mmol), toluene (6.82 mL),
vinyltrimethylsilane (0.684 g, 6.82 mmol), and 9-vinylcarbazole
(2.64 g, 13.64 mmol) were placed in a 15 mL glass ampule.
The ampule was sealed and heated at 80 °C for 20 h. The final
product was separated from residues of the catalyst and the
remaining olefin using column with silica (hexane/EtOAc )
50:1, Rf ) 0.65), to afford 1.09 g of 1 (4.11 mmol, 60% yield) as
white and less-yellow crystals, mp 93.2-94.8 °C. 1H NMR
Experimental Section
General Methods. 1H NMR (300 MHz), 13C NMR (75
MHz), 29Si NMR (60 MHz), and DEPT spectra were recorded
on a 300 MHz spectrometer in C6D6 (or CD3COCD3, CDCl3)
solution. Chemical shifts are reported in δ (ppm) with reference
to the residue solvent (CH3Cl) peak for 1H and 13C and to TMS
for 29Si. Analytical gas chromatographic (GC) analyses were
performed on a DB-5 fused silica capillary column (30 m ×
0.15 mm) and TCD. Mass spectra of the monomers and
products were obtained by GC-MS analysis (with a BD-5
capillary column (30 m) and an ion trap detector. High-
resolution mass spectroscopic (HRMS) analyses were per-
formed on a mass spectrometer. Thin-layer chromatography
(TLC) was made on plates coated with 250 µm thick silica gel,
and column chromatography was conducted with silica gel 60
(70-230 mesh). Benzene and hexane were dried by distillation
from sodium hydride, similarly toluene and diethyl ether were
distilled from sodium and hexane from calcium hydride under
argon. All liquid substrates were also dried and degassed by
bulb-to-bulb distillation. All reactions were carried out under
dry argon atmosphere. Melting points are uncorrected and
were determined by using a melting point apparatus.
(C6D6, δ (ppm)): 0.19 (s, 9H, (Si(CH3)3), 5.93 (d, 1H, JH-H
)
17.1 Hz, -HCdCH-Si), 7.36 (t, 1H, Ph), 7.59 (t, 1H, Ph), 7.60
(d, 1H, Ph), 7.85 (d, 1H, JH-H ) 17.0 Hz, -HCdCH-N), 7.96 (d,
1H, Ph). 13C NMR (C6D6, δ (ppm)): - 0.8, 111.2, 113.0, 120.6,
121.2, 124.8, 126.2, 133.5, 139.8. 29Si NMR (C6D6, δ (ppm)):
- 5.09. HRMS calcd for C17H19NSi: 265.12868, found 265.12999.
Anal. Calcd for C17H19NSi: C 76.93, H 7.22, N 5.28. Found:
C 76.64, H 7.20, N 5.26. Single crystals of 1 suitable for X-ray
crystal structure were obtained by recrystallization from
diethyl ether/hexane.
(E)-9-[2-(Dimethylphenylsilyl)ethenyl]-9H-carbazole (2).
[RuH(Cl)(CO)(PCy3)2] (I) (49 mg, 0.068 mmol), toluene (6.82
mL), vinyldimethylphenylsilane (1.107 g, 6.82 mmol), and
9-vinylcarbazole (1.45 g, 7.50 mmol) were placed in a 20 mL
glass minireactor. The mixture was heated at 105-110 °C for
20 h under an argon flow. After disappearance of the sub-
strates was confirmed by GC analysis, the solvent was
evaporated under vacuum and the final fraction was injected
Materials. The following chemicals were used: benzene,
CH2Cl2, EtOAc, toluene, decane, dodecane, diethyl ether,
tetrahydrofurane, hexane, iodobenzene, tetrabutylammonium
fluoride (TBAF), 9-vinylcarbazole, vinyltrimethylsilane, vi-
nyldimethylphenylsilane, vinyltriethoxysilane, C6D6, CD3-
COCD3, and Grubbs’ catalysts, [RuCl2(PCy3)2(dCHPh)] (II)
(10) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467-473.
(11) (a) Yi C. S.; Lee D. W.; Chen, Y. Organometallics 1999, 18, 2043.
(b) Ukai, T.; Kawazura, H.; Ishii, Y. J. Organomet. Chem. 1974, 65,
253.
8554 J. Org. Chem., Vol. 70, No. 21, 2005