Improving sustainability in ene-yne cross-metathesis for transformation of unsaturated fatty esters

Article abstract of DOI:10.1002/cssc.201000212

Ruthenium-catalyzed ene-yne cross-metathesis is performed with stoichiometric proportions of terminal olefins and alkynes. This is made possible by the continuous addition of the alkyne to the reaction mixture. The protocol allows the ene-yne cross-metathesis reaction to be carried out with long-chain terminal olefins and in a one-pot fashion with internal olefins after shortening by ethenolysis. The efficient conversion of renewable unsaturated fatty esters from bioresources into valuable conjugated 1,3-dienes of interest for further transformations is performed using this technique under mild conditions in dimethyl carbonate; an ecofriendly solvent. Environmentally ene-yne: A ruthenium-catalyzed ene-yne cross-metathesis reaction is performed with stoichiometric amounts of terminal olefins and alkynes. The alkyne is added to the reaction mixture continuously. The protocol allows ene-yne cross-metathesis reaction to be carried out with long-chain terminal olefins and with internal olefins after shortening by ethenolysis in dimethyl carbonate as solvent.

Full text of DOI:10.1002/cssc.201000212

DOI: 10.1002/cssc.201000212
Improving Sustainability in Ene–Yne Cross-Metathesis for
Transformation of Unsaturated Fatty Esters
Virginie Le Ravalec, Antoine Dupꢀ, Cꢀdric Fischmeister, and Christian Bruneau*[a]
Ruthenium-catalyzed ene–yne cross-metathesis is performed
with stoichiometric proportions of terminal olefins and alkynes.
This is made possible by the continuous addition of the alkyne
to the reaction mixture. The protocol allows the ene–yne
cross-metathesis reaction to be carried out with long-chain ter-
minal olefins and in a one-pot fashion with internal olefins
after shortening by ethenolysis. The efficient conversion of re-
newable unsaturated fatty esters from bioresources into valua-
ble conjugated 1,3-dienes of interest for further transforma-
tions is performed using this technique under mild conditions
in dimethyl carbonate; an ecofriendly solvent.
Introduction
Results and Discussion
Enyne ring-closing metathesis and ene–yne cross-metathesis
are very efficient reactions for the atom-economical production
of conjugated dienes.[1] Enyne ring-closing metathesis has
been used for the construction of cyclic dienes with one endo-
and one exo-cyclic double bond, followed by further Diels–
Alder reactions to prepare natural and non-natural products of
biological interest.[2] The bimolecular version, first introduced
by Mori and co-workers with ethylene and by Blechert and co-
workers with higher terminal alkenes in 1997,[3] has been less
investigated. The reaction is generally performed with rutheni-
um carbene catalysts, in the presence of excess olefin, because
of the possible olefin self-metathesis side reaction, to reach
complete conversion of the alkyne.
We recently found that the cross-metathesis of dec-1-ene 1
and methyl dec-9-enoate 2 arising from ethenolysis of methyl
oleate with the symmetrical 1,4-but-2-yndiyl diacetate 3 in the
presence of the ruthenium catalyst I leads to the formation of
the expected conjugated dienes 4 and 5 (Scheme 1).[10]
A
study of the influence of temperature and olefin/alkyne ratio
revealed that an excess of olefin is necessary to achieve com-
plete conversion of the alkyne (Table 1).
These results showed that the most efficient cross-metathe-
sis reaction was performed in toluene, using 1 mol% of cata-
lyst I and a twofold excess of alkene. However, the presence of
the excess dec-1-ene favored its self-metathesis, leading to
equal amounts of the symmetrical C18 internal olefin 6 and
ethylene, which reacted in a secondary ene–yne cross-meta-
thesis to give diene 7.[3a,11]
Recently, there has been a renewed interest in vegetable
fats and oils as alternatives to petrochemical compounds.[4]
These natural resources were mostly used after transformation
of their carboxylic functionality or oxidation of their unsaturat-
ed carbon–carbon double bonds. Recently, metathesis reac-
tions have been used for the transformation of fats and oils,
furnishing valuable materials for the chemical industry.[5]
During the last ten years, the homogeneously catalyzed ethe-
nolysis,[6] self-metathesis,[7] cross-metathesis,[8] and polymeri-
zation[9] of various types of olefins has been developed.
We recently reported the first example of ene–yne cross-
metathesis involving unsaturated fatty esters bearing a termi-
nal olefinic group with a functional alkyne, such as propargylic
esters or carbonates.[10] Despite the very good results obtained
in these catalytic reactions, the transformations had to be per-
formed with a twofold excess of the olefin. Besides the expect-
ed products, these experimental conditions led to excess olefin
and olefin self-metathesis byproducts, making product separa-
tion and olefin recovery difficult, thus reducing the applicabili-
ty and sustainability of this reaction.
Indeed, we found that ene–yne
cross-metathesis of 3 with ethyl-
ene (under ethylene atmosphere)
took place with quantitative con-
version of 3 in the presence of
2.5 mol% of catalyst I in toluene at
room temperature after 3 h. The
same reaction was reported in the
presence of Grubbs first-genera-
tion catalyst.[3a,11] For this reason Mori’s conditions, which are
based on the addition of ethylene, favoring the formation of
reactive ruthenium methylidene species, could not be used in
this special case.
The use of excess olefin in ene–yne cross-metathesis is a
classical procedure. This is especially true when ethylene is
used as a reagent, but in this case it does not create any com-
[a] V. Le Ravalec, A. Dupꢀ, Dr. C. Fischmeister, Dr. C. Bruneau
UMR 6226 CNRS Sciences Chimiques de Rennes
Universitꢀ de Rennes 1, Catalyse et Organomꢀtalliques, Bꢁt 10C
Av. du Gꢀnꢀral Leclerc, 35042 Rennes Cedex (France)
Fax: (+33)02 23 23 69 39
We report here that a process based on the continuous ad-
dition of the alkyne to the olefin makes the utilization of stoi-
chiometric amounts of substrates possible.
E-mail: christian.bruneau@univ-rennes1.fr
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C. Bruneau et al.
Figure 1. Reaction profiles for different product ratios as a function of time.
The ratios were determined by integration versus an internal standard.
thesis of 1 so that after 30 min only a few percent of octadec-
9-ene 6 was produced, but the amount of 6 formed increased
rapidly once the alkyne was consumed. In the closed reactor,
with longer reaction times, the formation of 6 from 1 in-
creased until the self-metathesis equilibrium was reached.
Owing to little self-metathesis reactivity, the formation of by-
product 7 at 30 min reaction time was also limited.
Scheme 1. Cross-metathesis of 3 with dec-1-ene 1 and methyl dec-9-enoate
2.
To secure the experimental protocol and avoid the forma-
tion of the self-metathesis product 6 and diene 7 we tested a
continuous addition of alkyne, aiming at maintaining an excess
of alkene during the reaction while using a stoichiometric pro-
portion of olefin and alkyne in order to avoid the presence of
excess olefin at the end of the reaction, which is the source of
trouble after the ene–yne cross-metathesis is completed. In ad-
dition, a more efficient use of the olefin would make the pro-
cess more sustainable, in particular when these olefins arise
from renewable materials. Thus, in a Schlenk tube were initially
introduced 1.5 mL of solvent, 0.6 mmol (1 equiv) of dec-1-ene
1, 0.3 mmol (0.5 equiv) of alkyne 3, and 0.006 mmol
(0.01 equiv) of catalyst I. Under these initial conditions, the
ene–yne cross-metathesis started with a 2:1 olefin/alkyne ratio.
The reaction mixture was then heated to 408C and the remain-
ing 0.5 equiv of alkyne 3 diluted in 1 mL of solvent was added
regularly via a syringe pump within 30 min. After complete in-
troduction of the alkyne, the reaction was prolonged for
30 min at 408C.
Then, gas chromatography analyses showed that (1)the con-
version of the alkyne was very high; (2) no terminal olefin was
detected; and (3) the by-products 6 and 7 were formed only in
trace amounts, and these amounts could not increase with
prolonged heating because dec-1-ene 1 was no longer avail-
able. It should be noticed that this technique, that is, slow ad-
dition of alkyne, has been reported for the cross-metathesis of
tetrahydroindene, featuring two distant internal double bonds,
with terminal alkynes to perform selective ring expansion, but
the main goal in this case was to prevent alkyne oligomeriza-
tion.[15]
Table 1. Influence of catalyst loading and olefin/alkyne ratio.[a]
Entry
Catalyst[b]
[mol%]
Olefin/alkyne
molar ratio
Conversion[c]
[%]
1
2
3
4
I(0.5)
I(1%)
I(1%)
I(1%)
2
1
1.5
2
47
53
65
100
[a] Cross-metathesis of 1 and 3 in toluene at 408C, reaction time 3 h.
[b] Catalyst loading based on the alkyne. [c] Conversion based on the
alkyne.
plications because the olefin self-metathesis is unproductive
and the excess ethylene is easily removed. In all reported ex-
amples involving homogeneous catalysis conditions, olefin/
alkyne ratios located within the range 9:1–2:1 were used to
ensure good conversion of the alkyne.[13] Because it has already
been demonstrated that some 1,3-dienes could perform cross-
metathesis with an olefin,[14] we checked if formation of 4
could arise from the cross-metathesis of 1 and 7. Under our
conditions the reaction of 1 with 7 showed no conversion, dis-
carding 7 as a possible intermediate.
We then studied the fate of the starting olefin 1 and alkyne
3, and the formed products as a function of time, starting from
a 2:1 olefin/alkyne ratio in the presence of 1 mol% of catalyst I
in toluene at 408C (Figure 1). We observed that the conversion
of the alkyne occurred without a noticeable initiation period
and was relatively fast, as it was complete within 30 min. The
ene–yne cross-metathesis was much faster than the self-meta-
This procedure was applied to the cross-metathesis of dec-
1-ene 1 and methyl undec-10-enoate 11, two olefins that can
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Improving Sustainability in Ene–Yne Cross-Metathesis
be sourced from biomass, with various terminal and internal
propargylic acetates and carbonates in toluene and dimethyl
carbonate.[16] The results are gathered in Tables 2 and 3.
When the reactions were carried out using a 2:1 olefin/
alkyne ratio, the GC analyses were performed after 30 min re-
action time, when the formation of the olefin self-metathesis
products 6 and 7 was still limit-
ed. Starting from dec-1-ene 1,
Table 2. Comparison of the two protocols for ene–yne cross-metathesis with dec-1-ene 1.
full conversion of the alkyne and
good GC yields of dienes 4, 8, 9,
10 were obtained. With the con-
tinuous addition technique, the
GC analyses were performed
after 1 h overall time. The con-
versions of alkynes were also ex-
cellent (90–100%), showing that
little dec-1-ene self-metathesis
took place, and the isolated
yields of diene were in the same
range as with the previous
method, isolation was easier due
to the absence of the starting
olefin.
2:1 ratio[a]
1:1 ratio[b]
Entry Alkyne
Diene
Conv.[c] GC yield[c] Yield[d] Conv.[c] GC yield[c] Yield[d]
[%]
[%]
[%]
[%]
[%]
[%]
100
100[e]
97
97
1
95
100
95
90
4
8
2
3
100
100
96
98
70
79
90
87
90
71
76
100
9
The new dienes 12–16 were
produced from substrate 11
(Table 3). From terminal alkynes
a perfect regioselectivity was ob-
tained, as previously observed
from 1 and 2.[10] The continuous
addition of alkyne was applied
in entries 1 and 3, and similar
conclusions could be drawn.
4
100
93
70
96
88
67
10
[a] General conditions: 1/alkyne ratio=2:1, catalyst I (1 mol%), solvent: toluene, 408C, 30 min. [b] General con-
ditions: 1/alkyne ratio=1:1, catalyst I (1 mol%), solvent: dimethyl carbonate, 1 equiv of 1 + 0.5 equiv of
alkyne, then 0.5 equiv of alkyne added in 30 min, 408C, 30 min. [c] Under conditions [a] and [b]: alkyne conver-
sion and diene GC yield of were determined by gas chromatography of the crude reaction mixture, with hexa-
decane as internal standard. [d] Isolated yield. [e] In dimethyl carbonate.
This new protocol makes a
more efficient use of the olefin
substrate, because in the con-
ventional method half of the
olefin is not used in the desired
reaction. This is of particular im-
portance when these olefins are
obtained from renewable materi-
als and used in one-pot transfor-
mations. This protocol, allowing
the use of stoichiometric
amounts of olefin and alkyne,
was then applied to a two-step
ethenolysis/ene–yne cross-meta-
thesis starting from methyl
oleate 17 in a one-pot proce-
dure (Scheme 2). As previously
reported, the ethenolysis of
0.3 mmol (1 equiv) of methyl
oleate was carried out in dimeth-
yl carbonate (DMC) at room tem-
perature in the presence of
2.5 mol% of catalyst II for
3 h.[10] Then, 1 mol% of catalyst
I and 0.3 mmol (1 equiv) of ethyl
but-1-yn-3-yl carbonate were
added to the reaction mixture,
heated at 408C. At the same
Table 3. Comparison of the two protocols for ene–yne cross-metathesis with methyl undec-10-enoate 11.
2:1 ratio[a]
1:1 ratio[b]
Entry Alkyne
Diene
Conv.[c] GC yield[c] Yield[d] Conv.[c] GC yield[c] Yield[d]
[%]
68
[%]
66
[%]
61
[%]
71
[%]
69
[%]
55
1
12
13
2
3
78
97
71
90
54
61
99
96
80
14
15
16
4
5
85
83
80
79
62
74
[a] General conditions: 11/alkyne ratio=2:1, catalyst I (1 mol%), solvent: dimethylcarbonate, 408C, 30 min.
[b] General conditions: 11/alkyne ratio=1:1, catalyst I (1 mol%), solvent: dimethylcarbonate, 1 equiv of 11 +
0.5 equiv of alkyne then 0.5 equiv of alkyne added in 30 min, 408C, 90 min. [c] Under conditions [a] and [b]:
alkyne conversion and diene GC yield of determined by gas chromatography of the crude reaction mixture,
with hexadecane as internal standard. [d] Isolated yield of diene based on the alkyne.
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C. Bruneau et al.
Scheme 2. One-pot ethenolysis/ene–yne cross-metathesis of methyl oleate 17 by using the continuous alkyne addition technique.
time, 0.3 mmol of ethyl but-1-yn-3-yl carbonate diluted in 1 mL
of DMC was added by syringe pump addition within 30 min,
and the solution was then maintained at 408C for 1 h. In this
case, the ethenolysis of methyl oleate generated 1.86 equiv of
terminal olefins (conversion 93%); the total quantity of alkynyl
carbonate corresponded to a slight excess with respect to the
two generated olefins. Dienes 9 and 18 (Scheme 2) were
formed in 84% and 94% GC yield with respect to the alkyne,
respectively.
ly described in Schemes 2 and 3. On the other hand, upon
ene–yne metathesis the other homoallylic fragment 21 led to
the new 6-hydroxy-1,3-diene 22.
It is noteworthy that the ethenolysis of 20 required a more
efficient catalyst than the ethenolysis of 17 and 19, and
1 mol% of catalyst III was used in diethyl carbonate (DEC) at
room temperature to ensure high conversion. The ene–yne
cross-metathesis under continuous addition of the alkyne was
then carried out with this catalyst, but again the reaction was
found to be more difficult and lower conversion (70%) was ob-
tained even at higher temperature (658C). Under these condi-
tions, compound 22 was isolated in moderate yield. Allylic al-
cohols are normally well-tolerated in enyne metathesis trans-
formations,[17] however, they can also lead to catalyst decom-
position.[18] Further optimization of this specific transformation
involving homoallylic alcohols will be necessary to address this
point.
Analysis of the gas chromatogram showed that almost no
byproducts resulting from secondary metathesis were formed,
and no intermediate terminal olefins were detected in signifi-
cant amounts. The regioselectivity and stereoselectivity were
identical to those observed when a 2:1 olefin/alkyne ratio was
used, that is, excellent regioselectivity and Z/E=0.45 for 9 and
0.1 for 18.[10]
Under similar experimental conditions, the symmetrical di-
methyl octadec-9-enedioate 19 was first subjected to ethenoly-
sis followed by cross-metathesis with ethyl but-1-yn-3-yl car-
bonate (Scheme 3). The sole diene 18 was obtained regioselec-
tively in 96% GC yield, with a Z/E stereoisomeric ratio of 0.14.
This value is better than the 91% GC yield (Z/E=0.1) obtained
with a 19/alkyne ratio of 2:1.
Finally, we studied the ethenolysis/ene–yne cross-metathesis
starting from methyl ricinoleate 20, another bioresource ex-
tracted from castor oil, with the propargylic carbonate but-1-
yn-3-yl carbonate (Scheme 4). As after ethenolysis of 17 and
19, methyl dec-9-enoate 2 was formed and the final product
18 incorporating this fatty fragment was the same as previous-
Conclusions
We have shown that it is possible to perform efficient ene–yne
cross-metathesis in the presence of the second-generation
Grubbs catalyst I, using stoichiometric amounts of olefin and
alkyne. This more-sustainable procedure, which allows the
presence of an excess of olefin up to the end of the reaction,
is based on continuous-flow addition of the alkyne. In terms of
catalytic efficiency, this protocol provides good results that are
comparable to those obtained starting from a twofold excess
of olefin at the outset of the reaction. However, this technique
presents two decisive advantag-
es: (1) there is no excess of
olefin to recover for its eventual
recycling, and (2) the renewable
material is almost fully converted
into 1,3-dienes. The terminal ole-
fins generated in the first trans-
formation are completely trans-
formed in the second step. The
application of this protocol in a
cascade transformation involving
ethenolysis followed by ene–yne
cross-metathesis in one pot pro-
vides a very efficient protocol to
transform bioresourced mono-
unsaturated fatty esters into
multifunctional dienes.
Scheme 3. One-pot ethenolysis/ene–yne cross-metathesis of diester 19 using continuous alkyne addition tech-
nique.
Scheme 4. Ethenolysis/ene–yne cross-metathesis starting from methyl ricinoleate 20 using alkyne continuous ad-
dition technique.
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Improving Sustainability in Ene–Yne Cross-Metathesis
(s, 1HE), 4.98 (s, 1HZ), 4.98 (s, 1HZ), 4.22–4.14 (s, 2HZ, 2HE), 3.66 (s,
3HE, 3HZ), 2.30 (t, 2HE, 2HZ, 3J=16.2 Hz), 2.18 (m, 2HZ), 2.09 (m, 2HE),
1.64–1.59 (m, 2HE, 2HZ), 1.44–1.25 ppm (m, 14HE, 14HZ); 13C NMR
(75 MHz, CDCl3): d=174.7, 154.9, 146.4, 144.7, 135.8, 132.1, 128.9,
125.5, 114.3, 112.6, 74.1, 64.2, 64.2, 51.9, 34.5, 33.5, 30.3, 29.7, 29.6,
29.5, 29.1, 25.3, 20.9, 20.2, 14.7 ppm; HR-MS: calculated for
C16H26O2: m/z=250.1933, found m/z=250.1919. Elemental analysis
calculated for C19H32O5: C 67.03, H 9.47; found: C 67.23, H 9.45.
Experimental Section
All reactions were carried out under an inert atmosphere of argon
by using Schlenk techniques. Solvents were freshly distilled and
dried prior to use according to classical procedures (CaH2 for di-
chloromethane, Na for THF and toluene). Dimethyl carbonate was
purchased from Alfa Aesar and stored over 4 ꢂ molecular sieves
after distillation. Ruthenium catalysts were purchased from Aldrich
and stored under argon. Compound 2 was purchased from Alfa
Aesar and used as-received. Methyl oleate 17 was purchased from
Fluka and used as-received. Diester 19 can be prepared using re-
ported procedure, see Ref. [10]. Methyl ricinoleate 20 was prepared
according to Ref. [19]. Alkyne precursors were prepared as report-
ed in Ref. [10]. Compounds 4,5, 8–10, and 24 are described in
Ref. [10]. Compounds 13, 15, and 16 were prepared according to
the protocol reported in Ref. [10]. Sample products were character-
ized by NMR using Bruker 200 dpx and Bruker avance 300 MHz
NMR spectrometers. Z/E ratios were determined by analogy to
compound 4, the isomers of which where identified by a NOESY
NMR experiment. Following NMR determination of the E/Z ratio,
this ratio could also be determined by gas chromatography. Gas
chromatography analyses were performed on a Shimadzu 2014
gas chromatograph with internal calibration. GC/MS analyses were
performed on a Shimadzu QP2010 apparatus.
Compound 15: 1H NMR (300 MHz, CDCl3): d=7.42–7.25 (m, 5HE,
3
5HZ), 6.32 (s, 1HE), 6.04 (s, 1HZ), 5.98 (d, J=16.1 Hz, 1HE), 5.76–5.66
(m, 1HE, 1HZ), 5.54 (dt, 3J=7.1 Hz, 3J=11.7 Hz, 1HZ), 5.45 (s, 1HZ),
5.27 (s, 1HE), 5.25 (s, 1HE), 5.14 (s, 1HZ), 4.23–4.14 (m, 2HE, 2HZ), 3.66
(s, 3HE, 3HZ), 2.27 (t, 2HE, 2HZ, 3J=7.6 Hz), 2.09 (m, 2HZ), 1.97 (m,
2HE), 1.61–1.57 (m, 2HE, 2HZ), 1.29–1.11 ppm (m, 11HE, 11HZ);
13C NMR (75 MHz, CDCl3): d=174.1, 154.3, 154.2, 143.7, 142.7,
137.8, 135.4, 132.8, 128.3, 128.2, 128.0, 127.4, 127.0, 125.1, 114.6,
114.0, 81.2, 78.6, 63.9, 51.3, 33.9, 32.8, 29.6, 29.2, 29.0, 29.0, 28.8,
28.7, 28.6, 24.8, 14.1 ppm; HR-MS: calculated for C24H34O5: m/z=
402.2406, found m/z=402.2402. Elemental analysis calculated for
C24H34O5: C 71.61, H 8.51; found: C 71.31, H 8.38.
Compound 16: 1H NMR (300 MHz, CDCl3): d=7.39–7.28 (m, 5HE,
3
5HZ), 6.52 (s, 1HE), 6.22 (s, 1HZ), 5.97 (d, J=16.1 Hz, 1HE), 5.73–5.63
(m, 1HE, 1HZ), 5.52 (dt, 3J=7.1 Hz, J=11.7 Hz, 1HZ), 5.37 (s, 1HZ),
5.21 (s, 1HE), 5.18 (s, 1HE), 5.09 (s, 1HZ), 3.66 (s, 3HE, 3HZ), 2.29 (m,
2HE, 2HZ), 2.11 (m, 3HE, 5HZ), 1.99 (m, 2HE), 1.63–1.58 (m, 2HE, 2HZ),
1.30–1.21 ppm (m, 11HE, 11HZ); 13C NMR (75 MHz, CDCl3): d=174.2,
169.9, 144.1, 138.6, 129.3, 128.6, 128.1, 127.6, 127.2, 114.1, 74.9,
51.4, 34.1, 33.0, 29.2, 29.1, 29.1, 29.0, 28.9, 24.9, 21.2 ppm; HR-MS:
calculated for C23H32O4Na: m/z=395.2198, found m/z=395.2194.
Elemental analysis calculated for C23H32O4: C 74.16, H 8.66; found:
C 74.12, H 8.69.
Synthesis of dienes 12 and 14 by the continuous addition method:
A Schlenk flask (15 mL capacity), under an argon atmosphere, was
loaded with 12 mg of catalyst I (0.014 mmol, 1 mol%), 0.238 g of
methyl undecenoate (1.2 mmol, 1 equiv), 30 mL of hexadecane (in-
ternal standard), 0.5 equivalent of alkyne (0.58 mmol), and 5 mL of
dimethyl carbonate. The mixture was then heated to 408C before
the final portion of the alkyne (0.58 mmol, 0.5eq) in 1 mL of di-
methyl carbonate was added over a period of 30 min via a syringe
pump apparatus. After 2 h (until the alkyne was consumed) a
sample was taken for GC analysis, and the solution was cooled to
room temperature. The solvent was evaporated and the crude oil
was purified by chromatography on silica gel with diethyl ether/
petroleum ether as the eluent to afford dienes 12 or 14 as color-
less oils.
Synthesis of diene 18 by the continuous addition method: A
Schlenk flask (15 mL capacity), under ethylene flow, was loaded
with 4.4 mg of catalyst II (0.007 mmol, 2.5 mol%), 0.087 g of meth-
yloleate 17 (0.295 mmol, 0.1 mL, 1.0 equiv), 26 mL of hexadecane
(internal standard), and 2.5 mL of diethyl carbonate. The solution
was stirred for 3 h at room temperature, and a sample was taken
for GC analysis. 0.5 equivalent of alkyne (0.29 mmol) and 5 mg of
catalyst II (0.006 mmol, 1 mol%) were added and the reaction was
heated to 408C. The final portion of the alkyne (0.29 mmol, 0.5 eq)
in 1 mL of dimethyl carbonate was added over a period of 30 min
via a syringe pump system, and mixture was left stirring at 408C
for a period of 1 h (until all the alkyne was consumed). After cool-
ing to room temperature and solvent evaporation, the crude oil
was purified by chromatography on silica gel with diethyl ether/
petroleum ether (98:2 v/v) as the eluent to give pure diene 18 in
60% yield.
Compound 12: 1H NMR (300 MHz, CDCl3): d=5.81 (t, 3J=7.5 Hz,
1HE), 5.65 (t, 3J=7.4 Hz, 1HZ), 5.31 (s, 1HE), 5.25 (s, 1HZ), 5.22 (s,
1HZ), 4.99 (s, 1HE), 4.80 (s, 2HZ), 4.75 (s, 2HZ), 4.60 (s, 2HE), 4.57 (s,
2HE), 3.66 (s, 3HE, 3HZ), 2.32–2.18 (m, 2HE, 4HZ), 2.08–2.04 (m, 8HE,
6HZ), 1.63–1.58 (m, 2HE, 2HZ), 1.42–1.23 ppm (m, 10HE, 10HZ);
13C NMR (75 MHz, CDCl3): d=174.3, 170.7, 140.5, 135.3, 134.5,
133.4, 131.5, 116.9, 114.5, 67.8, 65.7, 65.2, 59.8, 51.4, 34.1, 29.6, 29.5,
29.3, 29.2, 29.2, 29.1, 28.7, 28.3, 24.9, 21.0, 20.9 ppm; HR-MS: calcu-
lated for C20H32O6Na: m/z=391.2097, found m/z=391.2104. Ele-
mental analysis calculated for C20H32O6: C 65.19, H 8.75; found: C
65.58, H 8.93.
Compound 18: 1H NMR (300 MHz, CDCl3): d=6.00 (d, 1HE, 3J=
16.0 Hz), 5.83–5.74 (m, 1HE, 1HZ), 5.63 (dt, 1HZ, 3J=7.1 Hz, 3J=
Compound 13: 1H NMR (300 MHz, CDCl3): d=5.86 (t, 3J=7.4 Hz,
1HZ), 5.72 (t, 3J=7.4 Hz, 1HE), 5.38 (s, 1HE), 5.32 (s, 1HZ), 5.28 (s,
1HZ), 5.06 (s, 1HE), 4.87 (s, 2HZ), 4.80 (s, 2HZ), 4.66 (s, 2HE), 4.63 (s,
2HE), 4.24–4.14 (m, 4HE, 4HZ), 3.66 (s, 3HE, 3HZ), 2.32–2.21 (m, 2HE,
4HZ), 2.08 (m, 2HE), 1.63–1.58 (m, 2HE, 2HZ), 1.44–1.25 ppm (m,
16HE, 16HZ); 13C NMR (75 MHz, CDCl3): d=174.3, 154.9, 139.7,
135.6, 132.7, 117.9, 70.8, 68.7, 68.4, 64.1, 64.0, 63.9, 51.4, 34.1, 29.5,
29.3, 29.2, 29.1, 29.1, 28.7, 24.9, 14.2; HR-MS: calculated for
C22H36O8Na: m/z=451.2308, found m/z=451.2306. Elemental anal-
ysis calculated for C20H32O6: C 61.66, H 8.47; found: C 62.24, H 8.71
3
11.6 Hz), 5.40 (q, J=6.6 Hz, 1HE), 5.27 (s, 1HZ), 5.18–5.12 (m, 1HE,
1HZ), 5.04 (s, 1HE), 4.98 (s, 1HZ), 4.22–4.15 (m, 2HE, 2HZ), 3.66 (s, 3HE,
3HZ), 2.30 (t, 2HE, 2HZ, 3J=7.5 Hz), 2.18 (m, 2HZ,), 2.09 (m, 2HE),
1.64–1.59 (m, 2HE, 2HZ), 1.44–1.25 ppm (m, 14HE, 14HZ). 13C NMR
(75 MHz, CDCl3): d=174.4, 154.6, 146.1, 144.4, 135.4, 131.8, 128.7,
125.3, 114.0, 112.3, 73.9, 64.0, 63.9, 51.6, 34.2, 33.2, 30.0, 29.2, 29.1,
28.8, 25.1, 20.6, 19.9, 14.4 ppm. HR-MS calculated for C18H30O5Na:
m/z: 349.1991; found: m/z=349.1990. Elemental analysis calculat-
ed for C18H30O5: C 66.23, H 9.26; found: C 66.69, H 9.51.
1
3
Compound 14: H NMR (300 MHz, CDCl3): d=6.00 (d, J=16.2 Hz,
Synthesis of diene 22 by the continuous addition method: A
Schlenk flask (15 mL capacity), under ethylene flow, was loaded
with 3.8 mg of catalyst III (0.006 mmol, 1 mol%), 0.187 g of methyl
3
3
1HE), 5.84–5.74 (m, 1HE, 1HZ), 5.64 (s, J=7.2 Hz, J=11.7 Hz, 1HZ),
5.40 (q, J=6.7 Hz, 1HE), 5.27 (s, 1HZ), 5.18–5.12 (m, 1HZ, 1HE), 5.04
3
ChemSusChem 2010, 3, 1291 – 1297
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemsuschem.org
1295

C. Bruneau et al.
Machmꢅller, J. O. Metzger, M. Rꢅsh gen. Klaas, H. J. Schꢆfer, M. P.
Schneider, Angew. Chem. 2000, 112, 2292–2310; Angew. Chem. Int. Ed.
2000, 39, 2206–2224; f) K. Hill, Pure Appl. Chem. 2000, 72, 1255–1264.
[5] For Reviews, see: a) R. Malacea, P. H. Dixneuf, Alkene Metathesis and Re-
newable Materials: Selective Transformations of Plant Oils, in Green Meta-
thesis Chemistry (Eds.: V. Dragutan, A. Demonceau, I. Dragutan, E.
Sh. Finkelstein), Springer, Dordrecht 2009, pp. 185–206; b) M. A. R.
Meier, Macromol. Chem. Phys. 2009, 210, 1073–1079; c) A. Rybak, P. A.
Fokou, M. A. R. Meier, Eur. J. Lipid Sci. Technol. 2008, 110, 797–804;
d) B. M. Marvey, Int. J. Mol. Sci. 2008, 9, 1393–1406; e) J. C. Mol, Green
Chem. 2002, 4, 5–13; f) J. C. Mol, Top. Catal. 2004, 27, 97–103.
[6] Ethenolysis: a) S. C. Marinescu, R. R. Schrock, P. Mꢅller, A. H. Hoveyda, J.
Am. Chem. Soc. 2009, 131, 10840–10841; b) C. Thurier, C. Fischmeister,
C. Bruneau, H. Olivier-Bourbigou, P. H. Dixneuf, ChemSusChem 2008, 1,
118–122; c) Y. Schrodi, T. Ung, A. Vargas, G. Mkrtumyan, C. W. Lee, T. M.
Champagne, R. L. Pederson, S. H. Hong, Clean: Soil Air Water 2008, 36,
669–673; d) K. A. Burdett, L. D. Harris, P. Margl, B. R. Maughon, T. Mokh-
tar-Zadeh, P. C. Saucier, E. P. Wasserman, Organometallics 2004, 23,
2027–2047; e) G. S. Forman, R. M. Bellarbarba, R. P. Tooze, A. M. Z.
Slawin, R. Karch, R. Winde, J. Organomet. Chem. 2006, 691, 5513–5516;
f) T. H. Newman, C. L. Rand, K. A. Burdett, R. R. Maughon, D. L. Morrison,
E. P. Wasserman, WO 02/076920; g) R. H. Grubbs, S.-B. T. Nguyen, L. K.
Jonhson, M. A. Hillmyer, G. C. Fu, WO 96/04289; h) C. Thurier, H. Olivier-
Bourbigou, P. Dixneuf, G. Hillion, EP1698686, US 2006/0079704.
[7] Self-metathesis: a) P. A. Thomas, B. B. Marvey, Int. J. Mol. Sci. 2009, 10,
5020–5030; b) H. L. Ngo, T. H. Foglia, J. Am. Oil Chem. Soc. 2007, 84,
777–784; c) H. L. Ngo, K. Jones, T. H. Foglia, J. Am. Oil Chem. Soc. 2006,
83, 629–634; d) E. Verkuijlen, F. Kapteijn, J. C. Mol, C. Boelhouwer, J.
Chem. Soc. Chem. Commun. 1977, 198–201; e) J. C. Mol, J. Mol. Catal.
1994, 90, 185–199; f) P. B. van Dam, M. C. Mittelmeijer, C. J. Boelhouver,
J. Chem. Soc. Chem. Commun. 1972, 1221–1222.
ricinoleate 20, 30 mL of hexadecane (internal standard), and 4 mL
of diethyl carbonate. The solution was stirred for 3 h at room tem-
perature, and a sample was taken for GC analysis. The reaction was
heated to 1008C, then 0.5 equivalent of alkyne (0.29 mmol) and
15.2 mg of catalyst III (0.024 mmol, 4 mol%) were added. The final
portion of the alkyne (0.29 mmol, 0.5 eq) in 1 mL of dimethyl car-
bonate was added over a period of 30 min via a syringe pump
system, and the mixture was left stirring at 1008C for a period of
1 h (until all the alkyne was consumed). A sample was taken for GC
analysis. After cooling to room temperature and solvent evapora-
tion, the crude oil was purified by chromatography on silica gel
with diethyl ether/petroleum ether (98:2 v/v) as the eluent to give
pure diene 22 in 42% isolated yield.
Compound 22: 1H NMR (300 MHz, CDCl3): d=6.13 (d, 3J=16 Hz,
3
3
1HE), 6.03 (d, J=11.6 Hz, 1HZ), 5.90–5.71 (m, 1HE, 1HZ), 5.43 (q, J=
6.5 Hz, 1HE, 1HZ), 5.31 (s, 1HZ), 5.20 (s, 1HE), 5.12 (s, 1HE), 5.06 (s,
1HZ), 4.21 (q, J=7.1 Hz, 2HE, 2HZ), 3.68 (s, 1HE, 1HZ), 2.43–2.32 (m,
1HE, 2HZ), 2.26–2.17 (m, 1HE), 1.61–1.23 (m, 16HE, 16HZ), 0.90 ppm
(m, 3HE, 3HZ); 13C NMR (75 MHz, CDCl3): d=154.7, 146.2, 127.3,
127.2, 113.5, 73.7, 73.6, 71.2, 71.1, 64.0, 63.9, 63.8, 41.3, 41.2, 37.0,
36.9, 36.5, 31.9, 31.8, 29.4, 29.3, 25.7, 25.6; 22.6, 20.6, 20.5, 20.4,
19.7 ppm; HR-MS: calculated for C17H30O4Na: m/z=321.2042, found
m/z=321.2044.
Acknowledgements
The authors are grateful to the CNRS and to the Rꢀgion Bretagne
for a PhD grant to V.L.R., to ADEME and to the Rꢀgion Bretagne
for a PhD grant to A.D., and thank the European Commission
(NoE IDECAT, NMP3-CT-2005–011730) for support.
[8] Cross-metathesis: a) T. T. T. Ho, T. Jacobs, M. A. R. Meier, ChemSusChem
2009, 2, 749–754; b) R. Malacea, C. Fischmeister, C. Bruneau, J.-L.
Dubois, J.-L. Couturier, P. Dixneuf, Green Chem. 2009, 11, 152–155; c) X.
Miao, C. Fischmeister, C. Bruneau, P. H. Dixneuf, ChemSusChem 2009, 2,
542–545; d) T. Jacobs, A. Rybak, M. A. R. Meier, Appl. Catal. A: Gen.
2009, 353, 32–35; e) A. Rybak, M. A. R. Meier, Green Chem. 2008, 10,
1099–1104; f) A. Rybak, M. A. R. Meier, Green Chem. 2007, 9, 1356–
1361; g) J. Patel, S. Mujcinovic, W. Roy Jackson, A. J. Robinson, A. K. Ser-
elis, C. Such, Green Chem. 2006, 8, 450–454; h) J. Patel, J. Elaridi, W. Roy
Jackson, A. J. Robinson, A. K. Serelis, C. Such, Chem. Commun. 2005,
5546–5547; i) J.-L. Dubois, WO 2008/104722; j) T. W. Abraham, H. Kaido,
C. W. Lee, R. L. Pederson, Y. Schrodi, M. J. Tupy, WO 2008/048522.
[9] Polymerization: a) P. Henna, R. C. Larock, J. Appl. Polym. Sci. 2009, 112,
1788–1797; b) Y. Lu, R. C. Larock, ChemSusChem 2009, 2, 136–147;
c) T. C. Mauldin, K. Haman, X. Sheng, P. Henna, R. C. Larock, M. R. Kessler,
J. Polym. Sci. Part A 2008, 46, 6851–6860; d) P. H. Henna, M. R. Kessler,
R. C. Larock, Macromol. Mater. Eng. 2008, 293, 979–990.
Keywords: alkenes
· alkynes · methathesis · renewable
resources · ruthenium
[1] a) A. Kinoshita, M. Mori, Synlett 1994, 1020–1022; b) M. Mori, Ene–yne
Metathesis, in Handbook of Metathesis (Ed.: R. H. Grubbs), Wiley-VCH,
Weinheim 2003, pp. 176–204; c) M. Mori, J. Mol. Catal. A: Chem. 2004,
213, 73–79; d) S. T. Diver, A. Giessert, Chem. Rev. 2004, 104, 1317–1382;
e) S. J. Connon, S. Blechert, Top. Organomet. Chem. 2004, 11, 93–124;
f) P. Van de Weghe, P. Bisseret, N. Blanchard, J. Eustache, J. Organomet.
Chem. 2006, 691, 5078–5108; g) H. Villar, M. Frings, C. Bolm, Chem. Soc.
Rev. 2007, 36, 55–66; h) M. Mori, Adv. Synth. Catal. 2007, 349, 121–135;
i) C. S. Poulsen, R. Madsen, Synthesis 2003, 1–18.
[10] V. Le Ravalec, C. Fischmeister, C. Bruneau, Adv. Synth. Catal. 2009, 351,
1115–1122.
[11] J. A. Smulik, S. T. Diver, J. Org. Chem. 2000, 65, 1788–1792.
[12] a) M. Mori, N. Sakakibara, A. Kinoshita, J. Org. Chem. 1998, 63, 6082–
6083; b) A. G. Giessert, N. Brazis, S. T. Diver, Org. Lett. 2003, 5, 3819–
3822.
[2] a) S. Kotha, M. Meshram, A. Tiwari, Chem. Soc. Rev. 2009, 38, 2065–
2092; b) W. A. L. van Otterlo, C. B. de Koning, Chem. Rev. 2009, 109,
3743–3782; c) R. P. Murelli, S. Catalꢃn, M. P. Gamon, M. L. Snapper, Tetra-
hedron Lett. 2008, 49, 5714–5717; d) D. A. Clark, A. A. Kulkarni, K. Kal-
barczyk, B. Schertzer, S. T. Diver, J. Am. Chem. Soc. 2006, 128, 15632–
15636; e) R. Ben-Othman, M. Othman, S. Coste, B. Denoix, Tetrahedron
2008, 64, 559–567; f) S. Kotha, N. Sreenivasachary, Chem. Commun.
2000, 503–504; g) S. Kotha, N. Sreenivasachary, E. Brahmachary, Tetrahe-
dron Lett. 1998, 39, 2805–2808; h) D. Sꢀmeril, J. Le Nꢄtre, C. Bruneau,
P. H. Dixneuf, A. F. Kolomiets, S. N. Osipov, New J. Chem. 2001, 25, 16–
18; i) D. Sꢀmeril, M. Clꢀran, C. Bruneau, P. H. Dixneuf, Adv. Synth. Catal.
2001, 343, 184–187.
[3] a) A. Kinoshita, N. Sakakibara, M. Mori, J. Am. Chem. Soc. 1997, 119,
12388–12389; b) R. Stragies, M. Schuster, S. Blechert, Angew. Chem.
1997, 109, 2628–2630; Angew. Chem. Int. Ed. Engl. 1997, 36, 2518–
2520.
[4] a) A. Behr, J. Pꢀrez Gomes, Eur. J. Lipid Sci. Technol. 2010, 112, 31–50;
b) A. Behr, A. Westfechtel, J. Pꢀrez Gomes, Chem. Eng. Technol. 2008, 31,
700–714; c) A. Corma, S. Iborra, A. Velty, Chem. Rev. 2007, 107, 2411–
2502; d) M. A. R. Meier, J. O. Metzger, U. S Schubert, Chem. Soc. Rev.
2007, 36, 1788–1802; e) U. Biermann, W. Friedt, S. Lang, W. Luhs, G.
[13] a) K. P. Kalbarczyk, S. T. Diver, J. Org. Chem. 2009, 74, 2193–2196; b) D.
Castagnolo, L. Botta, M. Botta, J. Org. Chem. 2009, 74, 3172–3174 ; c) D.
Castagnolo, L. Botta, M. Botta, Tetrahedron Lett. 2009, 50, 1526–1528;
d) A. J. Giessert, S. T. Diver, Org. Lett. 2005, 7, 351–354; e) M. Kim, D.
Lee, Org. Lett. 2005, 7, 1865–1868; f) M. Kim, S. Park, S. V. Maifeld, D.
Lee, J. Am. Chem. Soc. 2004, 126, 10242–10243; g) A. J. Giessert, L.
Snyder, J. Markham, S. T. Diver, Org. Lett. 2003, 5, 1793–1796; h) S. Ro-
driguez-Conesa, P. Candal, C. Jimenez, J. Rodrıguez, Tetrahedron Lett.
2001, 42, 6699–6702; i) R. Stragies, U. Voigtmann, S. Blechert, Tetrahe-
dron Lett. 2000, 41, 5465–5468.
[14] a) H.-Y Lee, B. G. Kim, M. L. Snapper, Org. Lett. 2003, 5, 1855–1858;
b) M. S. M. Timmer, H. Ovaa, D. V. Filippov, G. A. van der Marel, J. H. van
Boom, Tetrahedron Lett. 2001, 42, 8231–8233; c) B. J. Albert, A. Sivara-
makrishnan, T. Naka, K. Koide, J. Am. Chem. Soc. 2006, 128, 2792; d) T.
Kitamura, Y. Sato, M. Mori, Tetrahedron 2004, 60, 9649–9657; e) P. Dewi,
S. Randl, S. Blechert, Tetrahedron Lett. 2005, 46, 577–580; f) F. Royer, C.
Vilain, L. Elkaꢇm, L. Grimaud, Org. Lett. 2003, 5, 2007–2009.
1296
www.chemsuschem.org
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemSusChem 2010, 3, 1291 – 1297

Improving Sustainability in Ene–Yne Cross-Metathesis
[15] S. T. Diver, D. A. Clark, A. A. Kulkarni, Tetrahedron 2008, 64, 6909–6919.
[16] X. Miao, C. Fischmeister, C. Bruneau, P. H. Dixneuf, ChemSusChem 2008,
1, 813–816.
[18] a) B. Schmidt, L. Staude, J. Org. Chem. 2009, 74, 9237–9240; b) A. Fꢅrst-
ner, O. R. Thiel, C. Lehmann, Organometallics 2002, 21, 331–335.
[19] L. Yang, H. Q. Wang, Z.-Y. Chen, Chem. Phys. Lipids 2002, 119, 23–31.
[17] a) D. A. Clark, J. R. Clark, S. Diver, Org. Lett. 2008, 10, 2055–2058; b) T.
Imahori, H. Ojima, Y. Yoshimura, H. Takahata, Chem. Eur. J. 2008, 14,
10762–10771.
Received: July 13, 2010
Published online on September 24, 2010
ChemSusChem 2010, 3, 1291 – 1297
ꢁ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemsuschem.org
1297