Novel olefin metathetis catalysts with fluorinated N-alkyl-N′-arylimidazolin-2-ylidene ligands

Article abstract of DOI:10.1007/s11172-017-1930-5

Novel ruthenium carbene complexes bearing unsymmetrical NHC-ligands based on N-alkyl-N′-arylimidazoline with hexafluoroisopropylmethoxy group in para-position of N-aryl moiety have been synthesized. Catalytic activity of complexes obtained was investigate

Full text of DOI:10.1007/s11172-017-1930-5

Russian Chemical Bulletin, International Edition, Vol. 66, No.9, pp. 1601—1606, September, 2017
1601
Novel olefin metathetis catalysts with fluorinated
NꢀalkylꢀN´ꢀarylimidazolinꢀ2ꢀylidene ligands*
S. M. Masoud,a T. R. Akmalov,a O. I. Artyushin,a C. Bruneau,b and S. N. Osipova
aA. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085. Eꢀmail: osipov@ineos.ac.ru
bCNRS ꢀUniversitй de Rennes 1, Institute des Sciences Chimique de Rennes, Organomйtalliques: Matйriaux et Catalyse,
Centre for Catalysis and Green Chemistry, Campus de Beaulieau, 35042 Rennes, France**
Novel ruthenium carbene complexes bearing unsymmetrical NHCꢀligands based on
NꢀalkylꢀN´ꢀarylimidazoline with hexafluoroisopropylmethoxy group in paraꢀposition of Nꢀaryl
moiety have been synthesized. Catalytic activity of complexes obtained was investigated on
model reactions of intraꢀ and intermolecular olefin metathesis.
Key words: fluorinated Nꢀheterocyclic carbenes, ruthenium carbene complexes, olefin
metathesis, catalysis.
Recent advances in development of novel rutheniumꢀ
based metathesis catalysts are associated mostly with
modification of Nꢀheterocyclic carbene (NꢀHC) ligand
in commercially available Grubbs GꢀII and Hoveyda HꢀII
complexes allowing for a direct tuning of the catalyst
efficiency.1—8 For example, varying electronic and steric
properties of substituents at the nitrogen atoms located in
direct proximity to a carbene center, one can significantꢀ
ly alter the catalytic activity, stability, and selectivity in
many types of metathesis transformations.
catalyst, encouraging the researches to search for novel
efficient catalytic systems.9
At the same time it is common knowledge that orgaꢀ
nofluorine compounds are widely used today in almost all
fields of science and technology including medicine and
manufacturing of novel materials. The reason is that fluꢀ
orine atoms or organofluorine substituents introduced in
an organic molecule significantly alter its physicoꢀchemꢀ
ical properties. This particularly holds true for trifluoroꢀ
methylated compounds as CF3 moiety is one of the most
lypophilic groups in organic chemistry, as well as highly
electronegative and bulky.10—15 As for rutheniumꢀbased
metathesis catalysts, steric and electronic effects of fluorꢀ
inated substituents on their catalytic activity has been
studied mainly for fluorineꢀmodified phosphine and styrene
ligands as well as in the case of substituting chlorine atoms
bonded to ruthenium, e.g. for fluoroalkoxy moieties.16—27
Presently, just a few examples of catalysts bearing fluoriꢀ
nated NꢀHCꢀligands are reported in literature.28—32
Recently, we developed synthetic procedures to obꢀ
tain novel metathesis catalysts with N,N´ꢀdiarylsubstiꢀ
tuted imidazolinilydene ligands having hexafluoroisoproꢀ
pylmethoxy group ((CF3)2(OMe)C—) in the Nꢀaryl subꢀ
stituent (1) and demonstrated high activity of these comꢀ
Therefore, unsymmetrical Nꢀheterocyclic carbenes
have currently assumed a new importance, since desymꢀ
metrization enables the further rapid tuning of catalytic
properties. Introduction of functional groups having
chelating, chirality or shielding effects can have a draꢀ
matic impact on stability, reactivity, and selectivity of a
* Dedicated to Academician of the Russian Academy of Sciences
G. A. Abakumov on the occasion of his 80th birthday.
** UMR 6226 CNRSꢀUniversiteì de Rennes 1, Institut des
Sciences Chimiques de Rennes, Organomйtalliques: Matériꢀ
aux et Catalyse, Centre for Catalysis and Green Chemistry,
Campus de Beaulieu, 35042 Rennes, France.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1601—1606, September, 2017.
1066ꢀ5285/17/6609ꢀ1601 © 2017 Springer Science+Business Media, Inc.

1602
Russ. Chem. Bull., Int. Ed., Vol. 66, No. 9, September, 2017
Masoud et al.
Scheme 1
Reagents and conditions: i. 20 °C, 24—48 h;
ii. toluene, 80 °C, 8 h; iii. 1) MeOH/HCl,
2) HC(OEt)3, 100 °C
Comꢀ
pound
a
b
c
R
Product yields (%)
3
4
5
But
Pri
Cy
95
96
98
99
79
87
80
99
99
* Cy is cyclohexyl.
plexes in reactions of intraꢀ and intermolecular olefin
metathesis.33—35
mercially available firstꢀgeneration Hoveyda complex HꢀI
(see Ref. 36) to the reaction mixture. Generally, slight
heating during 30—40 min was needed for the ligand
exchange reaction (PCy3 for NꢀHC) to be completed.
Resulting complexes 6a—c were isolated by column
chromatography on silica gel as darkꢀgreen powders
characteristic for phosphineꢀfree Hoveydaꢀtype comꢀ
plexes (HꢀII).
To elucidate the effect of more donor Nꢀalkyl substitꢀ
uents in the fluorinated NꢀHCꢀligand on activity of the
catalyst, in the present study we have synthesized the
corresponding ruthenium carbene complexes and perꢀ
formed the preliminary catalytic activity testing thereof.
Primarily, our efforts were focused on the synthesis of
unsymmetrical NꢀalkylꢀN´ꢀarylimidazolinium salts. For
this purpose, fluorinated anilide 2 was used as a starting
compound (Scheme 1) which is readily obtainable acꢀ
cording to our previous procedure36 starting from comꢀ
mercially available 2,6ꢀdimethylaniline, hexafluoroꢀ
acetone hydrate, and chloroacetyl chloride. Thus, it was
established that reaction of anilide 2 with primary amines
such as tertꢀbutylamine, isopropylamine, and cyclohexylꢀ
amine proceeds smoothly at room temperature without
solvent with an excess of amine and is completed within
1—3 days (TLC control) to produce the corresponding
aminoamides 3a—c in nearly quantitative yields (see
Scheme 1). Subsequent reduction of the amide keto group
in compounds 3a—c proceeds effectively using dimethylꢀ
sulfide complex of BH3 in toluene at 80 °C to give high
yields of diamines 4a—c. The latter readily undergo intraꢀ
molecular heterocyclization during the conventional
treatment using triethyl orthoformate to afford the deꢀ
sired imidazolinium salts 5a—c (see Scheme 1).
Scheme 2
The salts 5a—c thus obtained were further used as
precursors for the corresponding Nꢀheterocyclic rutheniꢀ
um complexes 6a—c (Scheme 2). Carbenes were generatꢀ
ed in situ by treating the parent salts 5a—c with potassium
hexamethyldisylazide (KHMDS) in anhydrous toluene
under argon at 0 °С followed by the addition of the comꢀ
Reagents and conditions: KHMDS, toluene, 0 °C→40 °C.
Yields (%): 70 (6a), 39 (6b), 25 (6c).

New olefin metathesis catalysts
Russ. Chem. Bull., Int. Ed., Vol. 66, No. 9, September, 2017 1603
C (%)
The complexes obtained were completely characterꢀ
ized by NMRꢀspectroscopy (1H, 13C, 19F), and elemenꢀ
tal analysis data. In the 1Н NMR spectra of all comꢀ
pounds characteristic signals of benzylidene protons
(Ru=C—H) are observed in the range of 16.5—17.1 ppm,
with the corresponding carbon atoms (Ru=C—H) rangꢀ
ing from 208—209 ppm in the 13С NMR spectra. Also,
the 13С NMR spectra show characteristic signals of carꢀ
bene atoms (N—C—N) at 306, 285, and 286 ppm for
compounds 6a, 6b, and 6c respectively.
Catalytic activity of complexes 6a—c synthesized was
tested in benchmark ringꢀclosing metathesis reactions
using diethyldiallyl malonate (DEDAM) and cross metꢀ
athesis of allylbenzene with 1,4ꢀdiacetoxybutꢀ2ꢀene.
Commercially available secondꢀgeneration Hoveyda catꢀ
alyst HꢀII as well as an unsymmetrical complex having
bisaryl NꢀHCꢀligand 1a obtained by us earlier,33 were
used as reference compounds.
HꢀII
100
1a
6b
80
60
6c
40
20
6a
0
0
6
12
18
24
30
36 42 48 τ/h
Fig. 1. Time dependency of DEDAM conversion of a catalyst
nature.
Scheme 4
Reagents and conditions: Ruꢀcatalyst (2.5 mol %), 0.1 М
CH2Cl2, 25 °С.
As a result, it was found that initiation rate for cataꢀ
lysts 6b and 6с in reaction with DEDAM proved to be far
lower compared to catalysts HꢀII and 1а; the highest
conversion (80%) was reached in reaction with isopropyl
derivative 6b for 48 h. Catalyst 6a bearing a bulky tertꢀBu
substituent at the nitrogen atom did not catalyze this proꢀ
cess (Scheme 3, Fig. 1).
C (%)
80
60
40
20
0
1a
HꢀII
6b
6c
Scheme 3
6a
0
0.5
1.0
1.5
2.0
2.5
3.0 τ/h
Reagents and conditions: Ruꢀcatalyst (1 mol %), 0.1 М CH2Cl2,
30 °С.
Fig. 2. Time dependency of allylbenzene conversion of a cataꢀ
lyst nature.
The similar tendency was observed for the cross metꢀ
athesis reaction of allylbenzene with 1,4ꢀdiacetoxybutꢀ2ꢀ
ene (Scheme 4, Fig. 2). In this case, catalyst 6b was the
most active, having reached the conversion values close
to those for HꢀII and 1a, however for a more prolonged
period of time (3 h). Similar to the reaction with DEDAM,
complex 6а proved to be absolutely inert.
To summarize, in the present study we have syntheꢀ
sized three novel unsymmetrical fluorinated ruthenium
carbene complexes having alkyl substituents at one of the
nitrogen atoms, and tested their catalytic activity in model
reactions of intraꢀ and intermolecular olefin metathesis.
It was found that replacing an aryl substituent by an alkyl
one decreases significantly the activity of the above comꢀ
plexes in the metathesis reactions studied. However the
moderate reactivity of isopropyl derivative 6b allows one
to expect its application in other types of metathesis such
as metathesis polymerization of bicyclic monomers where
the low initiation rate improves the polymer structure.8

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Russ. Chem. Bull., Int. Ed., Vol. 66, No. 9, September, 2017
Masoud et al.
126.1, 122.5 (q, CF3, 1JC,F = 290 Hz); 83.7—82.1 (m, C(CF3)2);
57.8, 54.4, 50.1, 34.0, 26.0, 25.1, 19.1. 19F NMR (CDCl3), δ:
–70.79. Found (%): C, 54.51; H, 5.85; N, 6.32. C20H26F6N2O2.
Calculated (%): C, 54.54; H, 5.95; N, 6.36.
Experimental
Solvents used in reactions were dried according to standard
procedures. Other reagents were recrystallized or distilled if
necessary. Ruthenium complexes were synthesized under argon
atmosphere using standard Schlenk techniques. The reactions
were monitored by TLC on Merck 60 F254 plates. The plates
were visualized using UV irradiation (254 and 366 nm), soluꢀ
tions of Ce(SO4)2 in 5% H2SO4 or KMnO4 in water. Column
chromatography was performed using silica gel Merck 60
(230 400 mesh ASTM) eluting with ethyl acetate—petroleum
ether. NMR spectra were measured at room temperature on
Bruker AVꢀ300 and Bruker AVꢀ400 instruments at an operating
frequences of 300 and 400 MHz for 1H; 75 and 101 MHz for
13C, and 282 and 376 MHz for 19F (CFCl3 was used as a stanꢀ
dard) respectively. The chemical shifts were referenced relaꢀ
tive to the residual undeuterated solvent peaks.
Synthesis of aminoamides 3 (general procedure). 2ꢀChloroꢀ
Nꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ2,6ꢀdiꢀ
methylphenyl]acetamide (2) (1.5 g, 4.0 mmol) was dissolved in
20ꢀfold excess of the corresponding amine (80 mmol). The
reaction mixture was stirred at room temperature until starting
compound 2 had been completely consumed (TLC control),
then the mixture was treated with 10% aqueous NaHCO3 soluꢀ
tion (20 mL) and extracted with ethyl acetate (3×20 mL). The
combined organic layer was washed with saturated aqueous
sodium chloride and water, then dried over MgSO4 and evapoꢀ
rated under reduced pressure. An excess of RNH2 was distilled
off in vacuo. The resulting solid was recrystallized from petroꢀ
leum ether.
Synthesis of diamines 4 (general procedure). Aminoamide 3
(2.9 mmol) was dissolved in anhydrous toluene (18 mL), then
BH3•SMe2 (7 mL of 2 M solution in THF, 13.0 mmol) was
added dropwise at room temperature under argon atmosphere.
The resulting mixture was stirred at 80 °C for 8 h. Then it was
cooled to room temperature and 10 mL of methanol and 20 mL
of 10% aqueous HCl were added slowly, followed by extraction
with ethyl acetate (2×30 mL). The aqueous solution was treatꢀ
ed with NaHCO3 and extracted with ethyl acetate (2×30 mL).
Combined organic layer after two extractions was washed with
saturated aqueous NaHCO3, dried over MgSO4, and evaporatꢀ
ed under reduced pressure.
N1ꢀtertꢀButylꢀN2ꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethoxyꢀ
propanꢀ2ꢀyl)ꢀ2,6ꢀdimethylphenyl]ethaneꢀ1,2ꢀdiamine (4a).
Yield 99%, m.p. 58—60 °C. 1H NMR (400 MHz, CDCl3), δ:
7.11 (s, 2 H, Harom); 4.09 (br. s, 2 H, NH); 3.45 (s, 3 H, OMe);
3.17 (t, 2 H, CH2, J = 5.6 Hz); 2.79 (t, 2 H, CH2, J = 5.6 Hz);
2.32 (s, 6 H, 2 Me); 1.12 (s, 9 H, C—Me3). 13C NMR (101 MHz,
CDCl3), δ: 148.6, 128.7, 127.8, 122.8 (q, CF3, 1JC,F = 291 Hz);
118.7, 83.9—82.2 (m, C(CF3)2); 54.1, 50.4, 48.7, 42.7, 29.3,
19.5. 19F NMR (CDCl3), δ: –70.99. Found (%): C, 54.17;
H, 6.85; N, 7.18. C18H26F6N2O. Calculated (%): C, 53.99;
H, 6.55; N, 7.00.
N1ꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ
2,6ꢀdimethylphenyl]ꢀN2ꢀisopropylethaneꢀ1,2ꢀdiamine (4b).
Yield 79%. Yellow oil. 1H NMR (400 MHz, CDCl3), δ: 7.12
(s, 2 H, Harom); 3.97 (br. s, 2 H, NH); 3.45 (s, 3 H, OMe); 3.21
(t, 2 H, CH2, J = 5.6 Hz); 2.93—2.84 (m, 3 H, CH2, CHMe2);
2.32 (s, 6 H, 2 Me); 1.12 (d, 6 H, CHMe2, J = 6.3 Hz).
13C NMR (101 MHz, CDCl3), δ: 148.4, 128.7, 128.3, 122.8 (q,
CF3, 1JC,F = 291 Hz); 119.1, 83.0 (hept, C(CF3)2, 2JC,F = 28 Hz);
54.1, 49.0, 47.5, 47.2, 22.7, 19.4. 19F NMR (CDCl3), δ:
–70.98. Found (%): C, 52.68; H, 6.26; N, 7.40. C17H24F6N2O.
Calculated (%): C, 52.85; H, 6.26; N, 7.25.
2ꢀ(tertꢀButylamino)ꢀNꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethꢀ
oxypropanꢀ2ꢀyl)ꢀ2,6ꢀdimethylphenyl]acetamide (3a). The reacꢀ
tion was completed within 3 days. Yield 95%, m.p. 126—128 °C.
1H NMR (400 MHz, CDCl3), δ: 9.19 (s, 1 H, NHСО); 7.27
(s, 2 H, Harom); 3.48 (s, 3 H, OMe); 3.43 (s, 2 H, CH2); 2.28
(s, 6 H, 2 Me); 1.70 (br. s, 1 H, NHCH2); 1.17 (s, 9 H, C—Me3).
13C NMR (101 MHz, CDCl3), δ: 171.2, 136.3, 135.7, 128.1,
126.1, 122.5 (q, CF3, 1JC,F = 290 Hz); 83.7—82.1 (m, C(CF3)2);
54.4, 51.4, 46.3, 29.2, 19.2. 19F NMR (CDCl3), δ: –70.79.
Found (%): C, 51.94; H, 5.89; N, 6.72. C18H24F6N2O2. Calcuꢀ
lated (%): C, 52.17; H, 5.84; N, 6.76.
N1ꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ
2,6ꢀdimethylphenyl]ꢀN2ꢀcyclohexylethaneꢀ1,2ꢀdiamine (4c).
Yield 87%, m.p. 171—173 °C. 1H NMR (400 MHz, CDCl3), δ:
7.11 (s, 2 H, Harom); 4.07 (br. s, 2 H, NH); 3.45 (s, 3 H, OMe);
3.25 (t, 2 H, CH2, J = 5.6); 2.92 (t, 2 H, CH2, J = 5.7 Hz);
2.61—2.52 (m, 1 H, Hcyclohexyl); 2.33 (s, 6 H, 2 Me); 2.04—1.10
(m, 10 H, Hcyclohexyl). 13C NMR (101 MHz, CDCl3), δ: 148.3,
128.7, 128.3, 122.8 (q, CF3, 1JC,F = 291 Hz); 119.2, 83.0 (hept,
Nꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ2,6ꢀ
dimethylphenyl]ꢀ2ꢀ(isopropylamino)acetamide (3b). The reacꢀ
tion was completed within 1 day. Yield 96%, m.p. 74—76 °C.
1H NMR (400 MHz, CDCl3), δ: 9.13 (s, 1 H, NHCO); 7.26
(s, 2 H, Harom); 3.47 (s, 5 H, CH2, OMe); 2.92 (hept, 1 H, CHMe2,
J = 6.1 Hz); 2.27 (s, 6 H, 2 Me); 2.21 (br. s, 1 H, NHCH2); 1.14
2
C(CF3)2, JC,F = 28 Hz); 57.0, 54.1, 47.1, 46.7, 32.9, 25.9,
25.0, 19.5. 19F NMR (CDCl3), δ: –70.97. Found (%): C, 56.62;
H, 6.75; N, 6.69. C20H28F6N2O. Calculated (%): C, 56.33;
H, 6.62; N, 6.57.
(d, 6 H, CHMe2, J = 6.2 Hz). 13C NMR (101 MHz, CDCl3), δ:
170.5, 136.5, 135.7, 128.0, 126.2, 122.5 (q, CF3, JC,F
1
=
= 289 Hz); 83.7—82.1 (m, C(CF3)2); 54.4, 50.3, 50.0, 23.0,
19.1. 19F NMR (CDCl3), δ: –70.80. Found (%): C, 50.87;
H, 5.59; N, 6.94. C17H22F6N2O2. Calculated (%): C, 51.00;
H, 5.54; N, 7.00.
Nꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ2,6ꢀ
dimethylphenyl]ꢀ2ꢀ(cyclohexylamino)acetamide (3c). The reacꢀ
tion was completed within 1 day. Yield 98%, m.p. 96—98 °C.
1H NMR (400 MHz, CDCl3), δ: 9.11 (br. s, 2 H, NHCO); 7.26
(s, 2 H, Harom); 3.47 (s, 5 H, CH2, OMe); 2.52—2.47 (m, 1 H,
Hcyclohexyl); 2.27 (s, 6 H, 2 Me); 1.96—1.06 (m, 10 H, Hcyclohexyl).
13C NMR (101 MHz, CDCl3), δ: 170.8, 136.2, 135.7, 128.0,
Synthesis of imidazolinium salts 5 (general procedure). Conꢀ
centrated hydrochloric acid (1 mL, 12 mmol) was added to
a solution of 4 (1.1 mmol) in MeOH (10 mL) and stirred for
10 min, followed by evaporation of the mixture at the reduced
pressure. The resulting solid dihydrochloride was dissolved in
the absolute orthoꢀxylene (60 mL), the mixture was refluxed
under argon for 10 min to remove the remaining water, then it
was cooled to room temperature and triethyl orthoformate
(200 μL, 1.1 mmol) was added. The resulting mixture was stirred
at 90 °C for 8 h. After the reaction was completed (TLC conꢀ
trol), all volatiles were removed under reduced pressure,

New olefin metathesis catalysts
Russ. Chem. Bull., Int. Ed., Vol. 66, No. 9, September, 2017 1605
the solid residue was rinsed with tetrahydrofurane and petroꢀ
leum ether.
291 Hz); 123.4, 122.6, 113.7, 84.0—82.9 (m, C(CF3)2); 74.6, 56.3,
54.2, 51.1, 45.8, 29.7, 22.4, 18.9. 19F NMR (C6D6), δ: –70.20.
Found (%): C, 47.87; H, 5.11; N, 3.86. C29H36Cl2F6N2O2Ru.
Calculated (%): C, 47.68; H, 4.97; N, 3.83.
1ꢀtertꢀButylꢀ3ꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethoxyproꢀ
panꢀ2ꢀyl)ꢀ2,6ꢀdimethylphenyl]ꢀ4,5ꢀdihydroꢀ1Hꢀimidazolꢀ3ꢀium
chloride (5a). Yield 80%, m.p. 220—222 °C (dec.). 1H NMR
(400 MHz, CDCl3), δ: 9.32 (s, 1 H, NCHN); 7.29 (s, 2 H,
Harom); 4.34 (s, 4 H, 2 CH2); 3.46 (s, 3 H, OMe); 2.44 (s, 6 H,
2 Me); 1.59 (s, 9 H, C—Me3). 13C NMR (101 MHz, CDCl3), δ:
157.5, 136.8, 135.4, 129.5, 128.8, 122.07 (q, CF3, 1JC,F = 289 Hz);
83.5—81.3 (m, C(CF3)2); 58.0, 54.6, 51.2, 46.7, 28.3, 18.8.
19F NMR (CDCl3), δ: –70.57. Found (%): C, 51.22; H, 5.79;
N, 6.22. C19H25ClF6N2O. Calculated (%): C, 51.07; H, 5.64;
N, 6.27.
Dichloro {3ꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethoxypropanꢀ
2ꢀyl)ꢀ2,6ꢀdimethylphenyl]ꢀ1ꢀisopropylꢀ4,5ꢀdihydroꢀ1Hꢀimidꢀ
azolꢀ2ꢀylidene}(2ꢀisopropoxybenzylidene)ruthenium(II) (6b).
Yield 39%. 1H NMR (400 MHz, C6D6), δ: 16.46 (s, 1 H, C=H);
7.59 (s, 2 H, Harom); 7.23—7.15 (m, 2 H, Harom); 6.79 (t, 1 H,
Harom, J = 7.4 Hz); 6.49 (d, 1 H, Harom, J = 8.2 Hz); 5.84 (hept,
1 H, NCHMe2, J = 5.8 Hz); 4.72 (hept, 1 H, OCHMe2,
J = 5.8 Hz); 3.29 (s, 3 H, OMe); 3.16—3.04 (m, 4 H, CH2);
2.25 (s, 6 H, 2 Me); 1.78 (d, 6 H, NCHMe2, J = 5.9 Hz); 1.56
(d, 6 H, OCHMe2, J = 6.3 Hz). 13C NMR (101 MHz, C6D6),
δ: 285.8, 208.1, 152.9, 144.8, 143.1, 140.3, 129.2, 128.8, 128.5,
123.3 (q, CF3, 1JC,F = 290 Hz); 122.6, 122.2, 113.3, 83.5 (hept,
3ꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ2,6ꢀ
dimethylphenyl]ꢀ1ꢀisopropylꢀ4,5ꢀdihydroꢀ1Hꢀimidazolꢀ3ꢀium
1
dichloride (5b). Yield 99%, m.p. 210—215 °C (dec.). H NMR
2
(400 MHz, DMSOꢀd6), δ: 9.00 (s, 1 H, NCHN); 7.43 (s, 2H,
Harom); 4.28—4.15 (m, 4 H, 2 CH2); 4.01 (hept, 1 H, CHMe2,
J = 6.5 Hz); 3.47 (s, 3 H, OMe); 2.41 (s, 6 H, 2 Me), 1.34
(d, 6 H, CHMe2, J = 6.6 Hz). 13C NMR (101 MHz, DMSOꢀd6),
δ: 157.4, 137.6, 136.3, 128.1, 127.8, 122.1 (q, CF3, 1JC,F = 292 Hz);
C(CF3)2, JC,F = 29 Hz); 75.1, 54.2, 52.9, 50.8, 41.8, 22.0,
20.7, 18.7. 19F NMR (C6D6), δ:–70.22. Found (%): C, 46.87;
H, 4.89; N, 3.99. C28H34Cl2F6N2O2Ru. Calculated (%): C, 46.93;
H, 4.78; N, 3.91.
Dichloro {1ꢀcyclohexylꢀ3ꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀ
methoxypropanꢀ2ꢀyl)ꢀ2,6ꢀdimethylphenyl]ꢀ4,5ꢀdihydroꢀ1Hꢀ
imidazolꢀ2ꢀylidene}(2ꢀisopropoxybenzylidene)ruthenium(II) (6с).
Yield 24%. 1H NMR (400 MHz, C6D6), δ: 16.41 (s, 1 H, C=H);
7.52 (s, 2 H, Harom); 7.20—7.07 (m, 2 H, Harom), 6.72 (t, 1 H,
Harom, J = 7.2 Hz); 6.43 (d, 1 H, Harom, JH,H = 8.1 Hz);
5.35—5.23 (m, 1 H, Hcyclohexyl); 4.65 (hept, 1 H, CHMe2,
3JH,H = 5.6 Hz); 3.21 (s, 3 H, OMe); 3.12 (s, 4 H, CH2);
2.78—2.67 (m, 2 H, Hcyclohexyl); 2.19 (s, 6 H, 2 Me); 1.93—1.64
(m, 5 H, Hcyclohexyl); 1.74 (d, 6 H, CHMe2, J = 5.5 Hz);
1.42—1.00 (m, 3 H, Hcyclohexyl). 13C NMR (101 MHz, C6D6),
δ: 286.0, 208.4, 152.9, 144.9, 143.0, 140.4, 129.1, 128.8, 128.5,
2
82.2 (hept, C(CF3)2, JC,F = 28 Hz); 54.6, 50.3, 49.9, 46.5,
20.4, 17.8. 19F NMR (DMSOꢀd6,), δ: –70.07. Found (%):
C, 50.13; H, 5.45; N, 6.45. C18H23ClF6N2O. Calculated (%):
C, 49.95; H, 5.36; N, 6.47.
3ꢀ[4ꢀ(1,1,1,3,3,3ꢀHexafluoroꢀ2ꢀmethoxypropanꢀ2ꢀyl)ꢀ2,6ꢀ
dimethylphenyl]ꢀ1ꢀcyclohexylꢀ4,5ꢀdihydroꢀ1Hꢀimidazolꢀ3ꢀium
chloride (5c). Yield 99%, m.p. 224—226 °C (dec.). 1H NMR
(400 MHz, DMSOꢀd6), δ: 9.09 (s, 1 H, NCHN); 7.42 (s, 2 H,
Harom); 4.24 (s, 4 H, 2 CH2); 3.71—3.61 (m, 1 H, Hcyclohexyl);
3.47 (s, 3 H, OMe); 2.41 (s, 6 H, 2 Me); 1.57 (m, 10 H, Hcyclohexyl).
13C NMR (101 MHz, DMSOꢀd6), δ: 157.4, 137.6, 136.3, 128.1,
1
1
127.7, 122.1 (q, CF3, JC,F = 290 Hz); 82.2 (hept, C(CF3)2,
123.4 (q, CF3, JC,F = 291 Hz); 122.6, 122.2, 113.3, 83.20
2JC,F = 28 Hz); 57.0, 54.6, 49.8, 47.0, 30.4, 24.6, 24.3, 17.8.
19F NMR (DMSOꢀd6,), δ: –70.10. Found (%): C, 53.13;
H, 5.84; N, 5.65. C21H27ClF6N2O. Calculated (%): C, 53.34;
H, 5.75; N, 5.92.
(hept, C(CF3)2, JC,F = 28 Hz); 74.9, 61.2, 54.2, 50.9, 43.3,
2
31.2, 26.3, 25.9, 22.1, 18.7. 19F NMR (C6D6), δ: –70.18.
Found (%): C, 48.95; H, 4.98; N, 3.83. C31H38Cl2F6N2O2Ru.
Calculated (%): C, 49.21; H, 5.06; N, 3.70.
Synthesis of ruthenium complexes 6 (general procedure). In
a flame dried Schlenk vial imidazolinium salt 5 (0.40 mmol)
was dispersed in anhydrous toluene ( 9 mL). The resulting mixꢀ
ture was cooled to 0 °C and degassed thrice, then KHMDS
(420 μL of 1 M solution in THF, 0.42 mmol) was added under
argon. The reaction mixture was stirred for 10 min at room
temperature and complex HꢀI (0.20 g, 0.33 mmol) was added,
the reaction mixture was stirred at 40 °C for 40 min. During this
time the mixture turned from brown to the darkꢀblue. After
completion of the reaction solvents were evaporated under reꢀ
duced pressure and green crystalline product was isolated using
column chromatography (eluting with petroleum ether—ethyl
acetate, 3 : 1).
The work was financially supported by the Russian
Science Foundation (Project No. 16ꢀ13ꢀ10364).
References
1. I. C. Stewart, T. Ung, A. A. Pletnev, J. M. Berlin, R. H.
Grubbs, Y. Schrodi, Org. Lett., 2007, 9, 1589.
2. C. Samojo owicz, M. Bieniek, K. Grela, Chem. Rev., 2009,
109, 3708.
3. G. C. Vougioukalakis, R. H. Grubbs, Chem. Rev., 2010,
110, 1746.
{1ꢀtertꢀButylꢀ3ꢀ[4ꢀ(1,1,1,3,3,3ꢀhexafluoroꢀ2ꢀmethoxyproꢀ
panꢀ2ꢀyl)ꢀ2,6ꢀdimethylphenyl]ꢀ4,5ꢀdihydroꢀ1Hꢀimidazolꢀ2ꢀylꢀ
idene}(dichloro)(2ꢀisopropoxybenzylidene)ruthenium(II) (6a).
Yield 70%. 1H NMR (400 MHz, C6D6), δ: 17.10 (s, 1 H, C=H);
7.54 (s, 2 H, Harom); 7.18 (t, 1 H, Harom, J = 8.0 Hz); 7.13 (d, 1 H,
Harom, J = 7.7 Hz); 6.73 (t, 1 H, Harom, J = 7.3 Hz); 6.45 (d, 1 H,
Harom, J = 8.1 Hz); 4.58 (hept, 1 H, CHMe2, 3JH,H = 5.9 Hz);
3.21 (s, 3 H, OMe); 3.15—3.01 (m, 4 H, 2 CH2); 2.29 (s, 6 H,
2 Me), 2.08 (s, 9 H, C—Me3); 1.53 (d, 6 H, CH(CH3)2,
J = 6.0 Hz). 13C NMR (101 MHz, C6D6), δ: 306.0, 209.1,
4. M. N. Hopkinson, C. Richter, M. Schedler, F. Glorius,
Nature, 2014, 510, 485.
5. S. J. Connon, S. Blechert, Recent Advances in Alkene Metaꢀ
thesis, in Ruthenium Catalysts and Fine Chemistry, Eds
C. Bruneau, P. H. Dixneuf, Springer, Heidelberg, 2004, 93.
6. A. H. Hoveyda, A. R. Zhugralin, Nature, 2007, 450, 243.
7. P. H. Deshmukh, S. Blechert, Dalton Trans., 2007, 2479.
8. K. Grela, Olefin Metathesis Theory and Practice, J. Wiley &
Sons: Hoboken, New Jersey, 2014.
9. J. Tornatzky, A. Kannenberg, S. Blechert, Dalton Trans.,
2012, 41, 8215.
153.0, 146.2, 144.5, 140.1, 130.5, 128.9, 123.4 (q, CF3, 1JC,F
=

1606
Russ. Chem. Bull., Int. Ed., Vol. 66, No. 9, September, 2017
Masoud et al.
10. P. Kirsch, Modern Fluoroorganic Chemistry, WileyꢀVCH,
Weinheim, 2004.
11. K. L. Kirk, J. Fluorine Chem., 2006, 127, 1013.
12. D. O´Hagan, Chem. Soc. Rev., 2008, 37, 308.
13. J. Nie, H.ꢀC. Guo, D. Cahard, J.ꢀA. Ma, Chem. Rev., 2011,
111, 455.
14. K. Uneyama, Organofluorine Chemistry, Blackwell, Oxford,
UK, 2006.
15. M. Jagodzinska, F. Huguenot, G. Candiani, M. Zanda,
ChemMedChem, 2009, 4, 49.
16. R. C. da Costa, J. A. Gladysz, Chem. Commun., 2006, 2619.
17. R. C. da Costa, J. A. Gladysz, Adv. Synth. Catal., 2007,
349, 243.
18. R. Tuba, R. C. da Costa, H. S. Bazzi, J. A. Gladysz, ACS
Catal., 2012, 2, 155.
19. M. Matsugi, D. P. Curran, J. Org. Chem., 2005, 70, 1636.
20. S. Leach, C. J. Cordier, D. Morton, G. J. McKierman,
S. Warriner, A. Nelson, J. Org. Chem., 2008, 73, 2753.
21. M. Matsugi, Y. Kobayashi, N. Suzumura, Y. Tsuchiya,
T. Shioiri, J. Org. Chem., 2010, 75, 7905.
26. T. S. Halbach, S. Mix, D. Fischer, S. Maechling, J. O.
Krause, C. Sievers, S. Blechert, O. Nuyken, M. R. Buchꢀ
meiser, J. Org. Chem., 2005, 70, 4687.
27. S. Monfette, K. D. Camm, S. I. Gorelsky, D. E. Fogg,
Organometallics, 2009, 28, 944.
28. S. Fustero, A. SimonꢀFuentes, P. Barrio, G. Haufe, Chem.
Rev., 2015, 115, 871.
29. V. Siano, I. d´Auria, F. Grisi, C. Costabile, P. Longo, Cent.
Eur. J. Chem., 2011, 9, 605.
30. A. Furstner, L. Ackermann, B. Gabor, R. Goddard, C. W.
Lehmann, R. Mynott, F. Stelzer, O. R. Thiel, Chem. Eur.
J., 2001, 7, 3236.
31. T. Ritter, M. W. Day, R. H. Grubbs, J. Am. Chem. Soc.,
2006, 128, 11768.
32. D. R. Anderson, D. J. O´Leary, R. H. Grubbs, Chem. Eur.
J., 2008, 14, 7536.
33. S. M. Masoud, A. K. Mailyan, V. Dorcet, T. Roisnel, P. H.
Dixneuf, C. Bruneau, S. N. Osipov, Organometallics, 2015,
34, 2305.
34. S. M. Masoud, A. K. Mailyan, A. S. Peregudov, C. Bruꢀ
neau, S. N. Osipov, Mendeleev Commun., 2016, 26, 474.
35. S. M. Masoud, M. A. Topchiy, A. S. Peregudov, T. Roisꢀ
nel, P. H. Dixneuf, C. Bruneau, S. N. Osipov, J. Fluorine
Chem., 2017, 200, 66.
22. J. Kví ala, M. Schindler, V. Kelbichová, M. Babunìk,
M. Rybá ková, M. Kví lová, J. Cva ka, A. B ezinová,
J. Fluorine Chem., 2013, 153, 12.
•
23. M. Babune´k, O. Šimunek, J. Hošek, M. Rybá ková,
J. Cva ka, A. B ezinová, J. Kví ala, J. Fluorine Chem., 2014,
161, 66.
36. J. S. Kingsbury, J. P. A. Harrity, B. L. Gray, A. H. Hoveyꢀ
da, J. Am. Chem. Soc., 1999, 121, 791.
24. Q. Yao, Y. Zhang, J. Am. Chem. Soc., 2004, 126, 74.
25. Y. Kobayashi, S. Inukai, N. Kondo, T. Watanabe, Y. Sugꢀ
iyama, H. Hamamoto, T. Shioiri, M. Matsugi, Tetrahedron
Lett., 2015, 56, 1363.
Received August 23, 2017;
in revised form August 28, 2017