Palladium-catalyzed reduction of olefins with triethylsilane

Article abstract of DOI:10.1016/S0040-4039(03)00981-X

The versatility of the palladium(II) chloride and triethylsilane system has been tested in the hydrogenation of 1-alkenes. The reduction of 1-alkenes was carried out in the presence of triethylsilane, ethanol and a catalytic amount of palladium(II) chloride, at room temperature. This facile and efficient method affords high yields for hydrogenation of unsaturated alkenes to the corresponding alkanes.

Full text of DOI:10.1016/S0040-4039(03)00981-X

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 4579–4580
Palladium-catalyzed reduction of olefins with triethylsilane
a,
b
a
a
Maryam Mirza-Aghayan, * Rabah Boukherroub, Mohammad Bolourtchian and Maryam Hosseini
a
Chemistry and Chemical Engineering Research Center of Iran (CCERCI), PO Box 14335-186, Tehran, Iran
b
Physique de la Mati e` re Condens e´ e, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau, France
Received 25 February 2003; revised 7 April 2003; accepted 16 April 2003
Abstract—The versatility of the palladium(II) chloride and triethylsilane system has been tested in the hydrogenation of 1-alkenes.
The reduction of 1-alkenes was carried out in the presence of triethylsilane, ethanol and a catalytic amount of palladium(II)
chloride, at room temperature. This facile and efficient method affords high yields for hydrogenation of unsaturated alkenes to
the corresponding alkanes. © 2003 Elsevier Science Ltd. All rights reserved.
Hydrogenation of unsaturated compounds is one of the
most important reactions in organic chemistry and
hence several reagents have been utilized for this pur-
Et SiH/PdCl was demonstrated for the conversion of
3 2
alcohols to their corresponding silyl ethers, halides and
7
alkanes, and for the efficient isomerization of 1-alkenes
1
8
pose. The addition of hydrogen to an alkene to form
to 2- and 3-alkenes.
the corresponding alkane is highly favored thermody-
namically. However, the reaction rate is negligible
under ordinary conditions in the absence of a catalyst.
Selective, mild and effective reducing agents in transi-
tion metal-catalyzed transfer hydrogenation have been
of considerable interest.
The present work was aimed at exploring the efficiency
of the system Et SiH/EtOH in the presence of catalytic
3
amounts of PdCl for hydrogenation of 1-alkenes under
2
mild conditions (Scheme 1). The hydrogenation reac-
tion requires the use of an inert atmosphere and anhy-
drous solvent. In a typical experiment: palladium
dichloride (10%) was added at room temperature to a
Trialkylsilanes are known to be poor reducing agents,
due to their low capacity to donate hydrogen atoms or
stirred mixture of the 1-olefin (1 equiv.) and Et SiH (2
2
3
hydrides. To overcome these limitations, a variety of
equiv.) in dry ethanol (2 ml). An exothermic reaction
took place in the first 5 min. and then the temperature
decreased to room temperature. The resulting mixture
was then stirred for 15 h at room temperature prior to
GC/MS analysis. The results obtained are summarized
in Table 1.
modified silanes with weaker SiꢀH bonds and com-
posite reducing systems based on a combination of a
3
silane/transition-metal catalyst have been developed.
4
Earlier work by Kursanov et al. described ionic hydro-
genation of carbonꢀcarbon double bonds and carbonyl
compounds using triethylsilane and an excess of tri-
5
fluoroacetic acid. Moreover, Lipowitz and Bowman
We tried different experimental conditions in order to
optimize the conversion of the 1-alkene to the corre-
sponding alkane. We found that the reaction of 1 equiv.
of 1-dodecene with Et SiH/PdCl (0.5 equiv./10%) for
have used polymethylhydrosiloxane (PMHS) and a pal-
ladium-on-charcoal catalyst for hydrogenating 1-alke-
nes in high yields at 40–60°C. However, the reaction of
3
2
2-nonene gave only 25% of the corresponding n-nonane
1
7 h at room temperature led to a lower yield of
under the same conditions.
n-dodecane (35%). Increasing the amount of Et SiH in
3
the reaction mixture (Et SiH/PdCl : 2 equiv./10%)
increased the conversion and the yield of n-dodecane to
3
2
More recently, palladium dichloride was used as the
catalyst for the conversion of organic halides to the
corresponding alkanes by triethylsilane at room temper-
6
ature in high yields. The versatility of the system
Keywords: hydrogenation; 1-alkenes; palladium(II) chloride; triethyl-
silane; ethanol.
*
Corresponding author. Tel.: +98 21 8036144-5; fax: +98 21 8037185.
Scheme 1.
0
040-4039/03/$ - see front matter © 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0040-4039(03)00981-X

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M. Mirza-Aghayan et al. / Tetrahedron Letters 44 (2003) 4579–4580
Table 1. Reduction of 1-alkenes using Et SiH/PdCl : 2/0.1
General procedure for reduction of h-olefins
3
2
in ethanol as solvent
To a solution of 1-alkene (0.2 g, 1 equiv.) and triethyl-
silane (2 equiv.) in 10 ml of ethanol was added a
catalytic amount of palladium(II) chloride (10 mol%)
under an argon atmosphere. The resulting mixture was
stirred for 15 h or 1.5 days at room temperature prior
to GC/MS analysis.
Entry
Time (days)
% Yielda
1
1
1
1
1
1
-Octene
-Decene
-Dodecene
-Tetradecene
-Hexadecene
-Octadecene
1
1
1.5
1
1.5
1
100
90
97
73
97
96
a
Determined by GC/MS analysis.
References
1
. (a) Johnstone, R. A. W.; Willby, A. H.; Entwistle, I. D.
Chem. Rev. 1985, 85, 129; (b) Kovacs, J.; Todd, T. D.;
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Organometallics 2000, 19, 3963; (c) Lee, S. H.; Park, Y. J.;
Yoon, C. M. Tetrahedron Lett. 2000, 41, 887.
7
3% (24% isomerized dodecenes were obtained). The
reaction time also has an influence on the product
distribution. The reaction of 1 equiv. of 1-dodecene
with Et SiH/PdCl (2 equiv./10%) for 1.5 days at room
3
2
temperature yielded 97% of n-dodecane. However,
three days were required to obtain a 92% conversion of
2. (a) Chatgilialoglu, C.; Ferreri, C.; Lucarini, M. J. Org.
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1-tetradecene to n-tetradecane.
In summary, this work demonstrates high efficiency for
reduction of alkenes to the corresponding alkanes using
PdCl , triethylsilane and ethanol as solvent, at room
2
temperature. It should be noted that no hydrosilylation
reaction took place during the hydrogenation process
and only the corresponding alkanes were obtained in
high yields.
4. Kursanov, D. N.; Parnes, Z. N.; Bassova, G. I.; Loim, N.
M.; Zdanovich, V. I. Tetrahedron 1967, 23, 2235–2242.
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All manipulations were carried out under an argon
atmosphere. Ethanol was distilled and stored under
argon. Yields are based on GC/MS analysis using a
FISON GC 8000 series TRIO 1000 gas chromatograph
equipped with a capillary column CP Sil.5 CB, 60
M×0.25 mm Id.
7. Ferreri, C.; Costantino, C.; Chatgilialoglu, C.; Boukher-
roub, R.; Manuel, G. J. Organomet. Chem. 1998, 554,
135–137.
8. Mirza-Aghayan, M.; Boukherroub, R.; Bolourtchian, M.;
Tabar-Hydar K.; Hoseini, M. J. Organomet. Chem.,
accepted for publication.