Renewable materials as precursors of linear nitrile-acid derivatives via cross-metathesis of fatty esters and acids with acrylonitrile and fumaronitrile

Article abstract of DOI:10.1039/b816917a

The cross-metathesis of fatty acids and esters, as renewable raw materials, with acrylonitrile and fumaronitrile is presented. The cross-metathesis reactions of both terminal and internal double bond containing compounds were performed using a ruthenium c

Full text of DOI:10.1039/b816917a

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Renewable materials as precursors of linear nitrile-acid derivatives via
cross-metathesis of fatty esters and acids with acrylonitrile and
fumaronitrile†
Raluca Malacea,a Ce´dric Fischmeister,a Christian Bruneau,*a Jean-Luc Dubois,b Jean-Luc Couturierb and
Pierre H. Dixneuf*a
Received 29th September 2008, Accepted 10th November 2008
First published as an Advance Article on the web 19th November 2008
DOI: 10.1039/b816917a
The cross-metathesis of fatty acids and esters, as renew-
able raw materials, with acrylonitrile and fumaronitrile is
presented. The cross-metathesis reactions of both terminal
and internal double bond containing compounds were per-
formed using a ruthenium catalyst and led to bifunctional
nitrile-esters or nitrile-acids with high conversions. The
tandem ruthenium catalysed cross-metathesis and hydro-
genation provide precursors of aminoacid monomers for
the production of polyamides from renewable resources.
We have thus considered the transformation via cross-
metathesis, with acrylonitrile, of two unsaturated acids and
their esters arising from renewable resources: the C11 ester
1 obtained from castor oil and its related carboxylic acid 2,
and the C18 diester 3 and diacid 4 obtained via biotrans-
formation or self-metathesis of oleic acid. (Scheme 2). Until
now, cross-metathesis of alkenes with acrylonitrile has been
studied only in some rare examples. The first example of cross
metathesis of terminal olefins with acrylonitrile was described
by Crowe and Goldberg,10 in the presence of the Schrock
=
catalyst Mo( CHCMe2Ph)(NAr)(OC–Me(CF3)2), Ar = 2,6-
Alkene metathesis catalysis1 has brought revolutions in synthetic
methodologies, by introducing an elegant way to make C–C
bonds and significantly reducing steps in complex architecture
synthesis,2 molecular material design3 and polymer science.4 It
has recently contributed to the development of green processes,5
including metathesis of fatty esters.6
Alkene cross-metathesis7 especially has the potential to give
added value to renewable materials, leading selectively to
unsaturated functional molecules. Plant oils and fats constitute
excellent renewable materials, as precursors of functional indus-
trial intermediates8 as demonstrated with the cross-metathesis of
fatty esters with acrylic esters offering a direct access to industry
relevant unsaturated diesters.9
diisopropylphenyl, affording moderate yields. Since then, ruthe-
nium catalysts have been used to perform cross-metathesis more
efficiently with acrylonitrile of organic substrates with an alkene
chain.11 To our knowledge, only one example of cross metathesis
between acrylonitrile and an internal double bond containing
olefin was described by Blechert, using the second generation
Grubbs catalyst and copper chloride as an additive.12
The cross metathesis of acrylonitrile and unsaturated acids or
=
esters, associated with the hydrogenation of both the C C and
CN bonds, constitutes a challenge and a potential strategic way
to generate from renewables linear aminoacid monomers useful
for the production of polyamides (Scheme 1).
Scheme 2 Synthesis of nitrile-acids and -esters 5–8 via cross-metathesis
with acrylonitrile.
We now report that the ruthenium catalyzed cross-metathesis
of acrylonitrile or fumaronitrile with fatty ester and acid 1 and
=
2, and internal C C bond containing derivatives 3 and 4 leads
to bifunctional nitrile-esters or acids 5–8, precursors of C12 and
C11 linear aminoacids (Scheme 2). The synthesis of saturated
nitrile esters by a tandem metathesis/hydrogenation sequence
using the residual metathesis ruthenium as the hydrogenation
catalyst is also presented.
Scheme 1 Synthesis of aminoacids and esters from renewable materials.
aLaboratoire Catalyse et Organome´talliques Institut Sciences Chimiques
de Rennes, UMR 6226 CNRS, Universite´ de Rennes Campus de
Beaulieu, 35042, Rennes, (France).
Cross-metathesis of acrylonitrile with the unsaturated ester 1 and
acid 2
E-mail: pierre.dixneuf@univ-rennes1.fr; Fax: (+33) 2 2323-6930;
Tel: (+33) 2 2323-6355
bARKEMA, CRRA, BP 63 Rue Henri Moissan, 69493, Pierre Be´nite,
(France)
The cross-metathesis of the unsaturated monoester 1 with an
excess of acrylonitrile (2 equiv.) was performed in toluene at
100 ◦C with the Grubbs I and Hoveyda II catalysts to give the
† Electronic supplementary information (ESI) available: Experimental
details. See DOI: 10.1039/b816917a
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Table 1 Cross-metathesis of 1 with acrylonitrilea
Acrylonitrile Cat.
Entry 1 (equiv.) (equiv.)
Convc
(mol%) t (h) (%)c
Z/Ed
1
2
3
1
1
1
1
1
2
2
2
2
2
I (5)
2
2
1
1
1
72
43
3.5/1
3.8/1
I (1)
II (5)
II (1)
II (1)
96 (86)e 2.6/1
Scheme 4 Cross-metathesis of 2 followed by esterification. a: I or
4
95
86
3.0/1
2.9/1
II (1 mol%), [2] = 0.05 M, toluene 100 ◦C. b: DMF-dimethylacetal,
5b
pyridine, 100 ◦C, 1 h.
a [1] = 0.05M, toluene, 100 ◦C. b [1] = 0.1M, toluene, 100 ◦C.
c Determined by gas chromatography. d Determined by gas chromatog-
raphy. e Isolated yield.
leading to bifunctional nitrile-acids, precursors of aminoacids.
The catalytic activity of I was significantly inhibited by the acidic
functionality since the conversion only reached 23% versus 43%
for the cross-metathesis of 1.
C12 nitrile ester 5 as a mixture of Z (major) and E isomers
(Fig. 1, Table 1). The Hoveyda catalyst II was found to be
the most efficient, allowing better conversion with low catalyst
loading (1%). It is important to note that increasing the reagents
concentration resulted in lower conversion (Table 1, entry 5).
Cross metathesis of the diester 3 and diacid 4 with acrylonitrile
The cross-metathesis with acrylonitrile of the symmetrical C18
diester 3 as a potential source of C11 nitrile-ester 7 was
attempted (Scheme 5).
Fig. 1 Ruthenium based olefin metathesis catalysts.
The possibility to synthesize saturated nitrile-esters from
renewable oils by tandem cross-metathesis/hydrogenation catal-
ysis was investigated. Thus, the crude reaction mixture, obtained
after cross metathesis using 1 mol% of II (Table 1, entry 4)
and containing residual ruthenium catalyst, was concentrated,
transferred to an autoclave, and hydrogenated without addi-
tional catalyst under 10 bar of H2 to quantitatively give a single
compound 9 (Scheme 3). This reaction provides an example
of two consecutive catalytic reactions using only one starting
ruthenium alkene metathesis catalyst in situ transformed into a
hydrogenation catalyst.13
Scheme 5 Cross metathesis of diester 3 with acrylonitrile.
As summarised in Table 2, catalysts I, II, and III promoted
the synthesis of the unsaturated nitrile-esters 7. Catalyst II was
again the most efficient one, when the diester 3 was reacted
with 4 equivalents of acrylonitrile in toluene at 100 ◦C for
1 h, but using 5 mol% of catalyst (Table 2, entries 2 and 4).
Compound 7 was obtained as a mixture of Z (major) and E
isomers. When the conversion was not complete, as observed
with I and III, large amounts of the monoester 11 (Scheme 5)
were formed (Table 2, entries 1,3). Longer reaction times did not
improve the conversion suggesting a rapid deactivation of the
catalyst during the first hour of reaction.14 Attempts to run the
reaction in acrylonitrile as solvent at 60 ◦C were not successful
and the starting diester 3 was recovered, and an increasing of
reagent concentration led to conversion decreasing (entries 2
and 7,8). The above results show that the cross-metathesis with
acrylonitrile of linear olefins containing an internal double bond
Scheme 3 Tandem cross-metathesis/hydrogenation.
The question of the relative easiness and efficiency of cross-
metathesis of unsaturated ester versus its carboxylic acid was
studied. The similar cross metathesis reaction was performed
starting with acid 2 (Scheme 4). In order to monitor the reaction
by gas chromatography, the crude products were esterified with
DMF-dimethylacetal. Both catalysts I and II were evaluated for
the transformation of 2 into 6 under the conditions previously
described for the transformation of 1. Catalyst II (1 mol%,
toluene) showed the best performances giving 90% conversion
in 1 h at 100 ◦C, the Z isomer being the major one (Z/E =
3.2/1) (Scheme 4). These experiments demonstrate that cross-
metathesis using catalyst II is not significantly affected by the
presence of an acidic functionality and that linear unsaturated
acids such as 2 can now be considered as direct starting materials
Table 2 Cross-metathesis of 3 with acrylonitrile a
Entry Catalyst (mol%) t/h T/◦C Conv. (%) Z/E 7/11
1
2
3
4
I (5)
2
1
2
100
100
100
100
60
60
100
100
75
99
61
68
—
—
86.5
64
2.8/1 2.9/1
2.6/1 20.7/1
2.8/1 2.1/1
2.8/1 3.4/1
II (5)
III (5)
II (1)
I (5)
1
5b
6b
7c
8d
19
19
3
—
—
—
—
II (5)
II (5)
II (5)
2.9/1 12/1
3.2/1 4.3/1
3
a 3 (1 mmol), acrylonitrile (4 mmol), 20 ml toluene [3] = 0.05 M. b 3
(1 mmol), 20 ml acrylonitrile. c [3] = 0.1 M. d [3] = 0.25 M.
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can be efficiently achieved, as it was also observed for the cross
metathesis with acrylic esters.9
Cross metathesis of acrylonitrile with methyl oleate 12
The methyl oleate 12 which presents an analogy with diester 3
for its internal double bond, was reacted with 2 or 4 equivalents
of acrylonitrile in toluene at 100 ◦C for 2 h with 5 mol%
of ruthenium catalyst II. This reaction proceeded with full
conversion of methyl oleate leading to a mixture of the expected
unsaturated nitrile 13 and nitrile ester 7 in equal proportions,
each of them being present in the reaction as a mixture of two
E and Z isomers (Scheme 8).
The crude reaction mixture of the nitrile-ester 7 was also
hydrogenated under 10 bars of H2, using the residual ruthenium
complex as the hydrogenation catalyst precursor. This tandem
metathesis/hydrogenation led to the quantitative formation of
the saturated nitrile-ester 10 (Scheme 3).
The direct cross-metathesis of the diacid 4 with acrylonitrile
was attempted using 5 mol% of II in toluene at 100 ◦C for
1 h (Scheme 6). The crude product was directly esterified by
treatment with DMF-dimethylacetal at 100 ◦C for 1 h to observe
90% conversion of 4 and the formation of 7 (Z/E = 2.4) and
11, with a 7/11 ratio = 23/1. Thus, the cross-metathesis with
=
acrylonitrile of internal CH CH bond containing derivatives
can be performed analogously for the diacid as for the diester
using 5 mol% of catalyst II.
Scheme 8 Cross-metathesis of methyl oleate with acrylonitrile.
The analogous reaction was performed using fumaronitrile
instead of acrylonitrile (Scheme 9). The reaction of 12 with one
or two equivalents of fumaronitrile in the presence of 5 mol%
of ruthenium complex II in toluene at 100 ◦C for 2 h also
proceeded quantitatively providing 7 and 13 as a mixture of
E and Z isomers, in equal proportion.
Scheme 6 a: II (5 mol%), toluene 100 ◦C. b: DMF-Dimethylacetal,
pyridine, 100 ◦C, 1 h.
For cross-metathesis of ester 1 and acid 2 no self-metathesis
product was observed, likely due to the profitable excess of
acrylonitrile.
Cross metathesis of diester 3 with fumaronitrile
Several attempts were made using fumaronitrile instead of
acrylonitrile as a source of unsaturated nitrile for the cross
metathesis with the diester 3 (Scheme 7). Using only 1% molar of
ruthenium complex II and two equivalents of fumaronitrile the
conversion reached 50% in 2 h but with higher catalyst loading
(5 mol%) the nitrile ester 7 was obtained in 92% isolated yield.
(Table 3, entries 2,3)
Scheme 9 Cross-metathesis of methyl oleate with fumaronitrile.
In conclusion, the above results show that the cross-metathesis
of both terminal and internal unsaturated esters and acids
with acrylonitrile, and even fumaronitrile, can be efficiently and
selectively performed using the Hoveyda catalyst II, without
isomerisation of initial substrates and products. These plant oil
derivatives have now become valuable sources of bifunctional
nitrile-acid derivatives. This catalytic cross-metathesis reaction,
which can be coupled with hydrogenation, offers potential
applications for the formation of a variety of bifunctional
nitrogen containing compounds from renewable raw materials
including aminoacids, the precursors of polyamides.
Experimental
Scheme 7 Cross-metathesis of diester 3 with fumaronitrile.
Table 3 Cross-metathesis of 3 with fumaronitrilea
General procedure for the cross-metathesis reactions.
Cross metathesis of C18 diester 3 with acrylonitrile
In a Schlenck tube under argon, 340 mg (1 mmol) of 3 and
212 mg (4 mmol, 4 equiv.) of acrylonitrile were dissolved in
20 mL of toluene before addition of 5 mol% of II and tetradecane
(10 mol%) as the gas chromatography internal standard. The
reaction mixture was then heated at 100 ◦C. Samples of the
reaction mixture were taken at different times under argon
atmosphere and then analyzed by GC analysis. Purification by
column chromatography using petroleum ether/diethyl ether
Entry
Catalyst (mol%)
Conv (%)b
1
2
3
4
I (1)
11
50
II (1)
II (5)
III (1)
97 (92)c
18
a 3 (1 mmol), fumaronitrile (2 mmol), 20 ml toluene, 100 ◦C, 2 h.
b Determined by gas chromatography. c Isolated yield.
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(9/1 and 8/2 v/v) as the eluent yielded 190 mg (86%) of 5
obtained as a colourless oil.
Top. Catal, 2004, 27, 97; (d) C. Thurier, C. Fischmeister, C. Bruneau,
H. Olivier-Bourbigou and P. H. Dixneuf, ChemSusChem, 2008, 1,
118; (e) M. B. Dinger and J. C. Mol, Adv. Synth. Catal., 2002, 344,
671; (f) H. Clavier, K. Grela, A. Kirschning, M. Mauduit and S.
Nolan, Angew. Chem., Int. Ed., 2007, 46, 6786.
Acknowledgements
6 (a) K. A. Burdett, L. D. Harris, P. Margl, B. R. Maughon,
T. Mokhtar-Zadeh, P. C. Saucier and E. P. Wasserman,
Organometallics, 2004, 23, 2027; (b) J. Patel, S. Mujcinovic, W. Roy
Jackson, A. J. Robinson, A. K. Serelis and C. Such, Green Chem.,
2006, 8, 450; (c) G. S. Forman, R. M. Bellarbarba, R. P. Tooze,
A. M. Z. Slawin, R. Karch and R. Winde, J. Organomet. Chem.,
2006, 691, 5513.
The authors are grateful to Arkema for post doctoral position to
RM and to CNRS and French Ministry of Research for support.
References
7 S. J. Connon and S. Blechert, Angew. Chem., Int. Ed., 2003, 42, 1900
1 (a) Y. Chauvin, Angew. Chem., Int. Ed., 2006, 45, 3740; (b) R. R.
Schrock, Angew. Chem., Int. Ed., 2006, 45, 3748; (c) R. H. Grubbs,
Angew. Chem., Int. Ed., 2006, 45, 3760; (d) Handbook of Metathesis,
ed. R. H. Grubbs, Volume 1–3 Wiley-VCH, Weinheim, 2003; (e) S. J.
Connon, S. Blechert, in Ruthenium Catalysts and Fine Chemistry,
ed. P. H. Dixneuf and C. Bruneau, Springer, 2004, vol. 11, p. 93;
(f) A. H. Hoveyda and A. R. Zhugralin, Nature, 2007, 450, 243;
(g) P. H. Deshmuhk and S. Blechert, Dalton Trans, 2007, 2479; (h) M.
Bieniek, A. Michrowska, D. L. Usanov and K. Grela, Chem. Eur. J.,
2008, 14, 806.
.
8 (a) U. Biermann, W. Friedt, S. Lang, W. Luhs, G. Machmuller, J. O.
¨
Metzger, M. Rush gen. Klaas, H. J. Schafer and M. P. Schneider,
Angew. Chem. Int. Ed., 2000, 39, 2206; (b) K. Hill, Pure Appl. Chem.,
2000, 7, 1255; (c) A. Corma, S. Iborra and A. Velty, Chem. Rev.,
2007, 6, 2503; (d) M. A. R. Meier, J. O. Metzger and U. S. Schubert,
Chem. Soc. Rev., 2007, 36, 1788; (e) A. Behr, A. Westfechtel and J.
Perez Gomes, Chem. Eng. Technol., 2008, 31, 700.
¨
¨
9 A. Rybak and M. A. R. Meier, Green Chem., 2007, 9, 1356.
10 W. E. Crowe and D. R. Goldberg, J. Am. Chem. Soc., 1995, 117, 5162.
11 (a) S. Gessler, S. Randl and S. Blechert, Tet. Lett., 2000, 41,
9973; (b) P. Dewi, S. Randl and S. Blechert, Tet. Lett., 2005, 46,
577; (c) J. A. Love, J. P. Morgan, T. M. Trnka and R. H. Grubbs,
Angew. Chem., Int. Ed., 2002, 41, 4035; (d) H. Hoveyda and M.
Vezina, Org. Lett., 2005, 7, 2113; (e) M. Bieniek, R. Bujok, M. Cabaj,
N. Lugan, G. Lavigne, D. Arlt and K. Grela, J. Am. Chem. Soc,
2006, 128, 13562; (f) C.-X. Bai, X.-B. Lu, R. He, W.-Z. Zhang and
X.-J. Feng, Org. Biomol. Chem., 2005, 3, 4139; (g) A. Michaut, T.
Boddaert, Y. Coquerel and J. Rodriguez, Synlett, 2007, 18, 2867;
(h) N. Vinokurov, J. R. Garabatos-Perera, Z. Zhao-Karger, M.
2 (a) K. C. Nicolaou, P. G. Bulger and D. Sarlah, Angew. Chem. Int.
Ed., 2005, 44, 4490; (b) A. Fu¨rstner, Angew. Chem., Int. Ed., 2000,
39, 3012.
3 (a) F. Pozgan, P. H. Dixneuf, in Metathesis Chemistry: From Nanos-
tructure Design to Synthesis of Advanced Materials, ed. Y. Imamoglu
and V. Dragutan, Springer, 2007, vol 243, 195–222; (b) H. Hou,
K. C-F. Leung, D. Lanni, A. Nelson, J. F. Stoddart and R. H. Grubbs,
J. Am. Chem. Soc., 2006, 128, 15358; (c) A. J. Nawara, T. Shima,
F. Hampel and J. A. Gladysz, J. Am. Chem. Soc., 2006, 128, 4962;
(d) A. F. M. Kilbinger, S. J. Cantrill, A. W. Waltman, M. W. Day and
R. H. Grubbs, Angew. Chem., Int. Ed., 2003, 42, 3281; (e) M. Weck,
B. Mohr, J.-P. Sauvage and R. H. Grubbs, J. Org. Chem., 1999, 64,
5463.
4 (a) M. R. Buchmeiser, Chem. Rev., 2000, 101, 1565; (b) J. E.
Schwendeman, A. Cameron Church and K. B. Wagener, Adv. Synth.
Catal., 2002, 344, 597.
5 (a) A. Rybak, P. A. Fokou and M. A. Meier, Eur. J. Lipid Sci. Technol.,
2008, 110, 797; (b) J. C. Mol, Green Chem., 2002, 4, 5; (c) J. C. Mol,
Wiebcke and H. Butenschon, Organometallics, 2008, 27, 1878.
12 M. Rivard and S. Blechert, Eur. J. Org. Chem., 2003, 2225.
13 (a) J. Louie, C. W. Bielawski and R. H. Grubbs, J. Am. Chem. Soc.,
¨
2001, 123, 11312; (b) A. Furstner and A. Leitner, Angew. Chem. Int.
Ed., 2003, 42, 308; (c) S. D. Drouin, F. Zamarian and D. E. Fogg,
Organometallics, 2001, 20, 5495; (d) B. Schmidt and M. Pohler, Org.
Biomol. Chem., 2003, 1, 2512.
¨
14 The Z/E ratio remained unchanged with longer reaction time.
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