ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 7, pp. 907–909. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © N.M. Shcheglova, V.D. Kolesnik, R.V. Ashirov, E.A. Krasnokutskaya, 2015, published in Zhurnal Organicheskoi Khimii, 2015,
Vol. 51, No. 7, pp. 927–929.
N-Chelate Ruthenium Carbene Complexes
in Olefin Metathesis and Isomerization
N. M. Shcheglovaa, V. D. Kolesnika, R. V. Ashirova, and E. A. Krasnokutskayab
a SIBUR Tomskneftekhim Chemical Research and Development Center,
ul. Kuzovlevskii trakt 2, build. 270, Tomsk, 634067 Russia; P.O. Box 1548
e-mail: Sheglova2006@rambler.ru
b National Research Tomsk Polytechnic University, pr. Lenina 30, Tomsk, 634050 Russia
Received March 9, 2015
Abstract—The catalytic activity of N-chelate ruthenium carbene complexes in the metathesis of hex-1-ene has
been studied in comparison to the second generation Grubbs catalyst.
DOI: 10.1134/S1070428015070015
Olefin metathesis in the presence of ruthenium
carbene complexes has found wide application in the
synthesis of organic compounds and polymers [1]. In
some cases, the reaction is accompanied by isomeriza-
tion [2] involving double bond migration. Undesirable
isomerization may be avoided by appropriate variation
of the catalyst structure [3, 4].
activities of complexes 1 and 2 were compared with
the activity of complex 3 which is a well known
second generation Grubbs catalyst [1, 7, 8].
Scheme 1.
[Ru], 80°C
Bu
Bu
Bu
H2C
The catalytic activity of recently reported com-
plexes 1 [5] and 2 [6] containing an N-chelating ben-
zylidene ligand has been studied only in ring-opening
metathesis polymerization and ring-closing metathesis
[5, 6]. The behavior of these complexes in cross meta-
thesis was not described, and their effect on the
isomerization during metathesis was not studied; these
issues were the subjects of the present study. As model
substrate we used hex-1-ene (Scheme 1). The catalytic
The reaction was carried out either under solvent-
free conditions or in 1,2-dichloroethane in the presence
of 0.01 mol % of complex 1 or 2 at 80°C. The product
composition was determined by gas chromatography
(see table). Complex 1 turned out to be the least active
in the metathesis of hex-1-ene, but it was more selec-
tive than 3. The catalytic activity of 2 approached that
of complex 3; however, it also favored isomerization,
and the selectivity was about 30%. We failed to sup-
press isomerization and obtain pure dec-5-ene using
a chlorinated solvent [1, 9].
PCy3
N
N
Mes
Mes
Cl
The presence of an N-chelating ligand in complexes
1 and 2 is expected to endow them with higher thermal
stability compared to complex 3 [10]. In fact, these
complexes were stable on heating the reaction mixture
to 150°C. The reaction catalyzed by complex 2 gave
a mixture of C2‒C29 olefins (see figure). Analogous set
of olefins is obtained in the large-scale Shell higher
olefin process (SHOP) for the manufacture of synthetic
oils [11]; this process includes three steps: oligomer-
ization of ethylene, isomerization, and metathesis.
Each step is catalyzed by its own catalyst. The use of
complex 2 could considerably enhance the efficiency
of this process (one step instead of three).
Cl
Ru
N
Cl
Ru
N
Cl
Me
Me
Me
Me
1
2
N
N
Mes
Mes
Cl
Cl
Me
Me
Ru
PCy3
3
907