Hybrid organic-inorganic materials derived from a monosilylated Hoveyda-type ligand as recyclable diene and enyne metathesis catalysts

Article abstract of DOI:10.1002/adsc.200600627

The synthesis of a monosilylated Hoveydatype monomer is described as well as the preparation of several organic-inorganic hybrid materials derived from it by sol-gel processes and by anchoring to commercial silica gel and MCM-41. The resulting materials w

Full text of DOI:10.1002/adsc.200600627

FULL PAPERS
DOI: 10.1002/adsc.200600627
Hybrid Organic-Inorganic Materials Derived from a
Monosilylated Hoveyda-type Ligand as Recyclable Diene and
Enyne Metathesis Catalysts
Xavier Elias,a Roser Pleixats,a,* Michel Wong Chi Man,b,* and Jol J. E. Moreaub
a
Chemistry Department, Universitat Autònoma de Barcelona, Cerdanyola del Vall›s, 08193 Barcelona, Spain
Fax : (+34)-93-581-1265; e-mail: roser.pleixats@uab.es
Institut Charles Gerhardt Montpellier (UMR 5253 CNRS-UM2-ENSCM-UM1), Architectures MolØculaires et MatØriaux
b
NanostructurØs, Ecole Nationale SupØrieure de Chimie de Montpellier, 8 rue de lꢀØcole normale, 34296 Montpellier cØdex
5, France
Fax : (+33)-4-6714-7212; e-mail: michel.wong-chi-man@enscm.fr
Received: December 6, 2006
Dedicated to the memory of Professor Marcial Moreno-MaÇas
Abstract: The synthesis of a monosilylated Hoveyda- lently bonded to the silica matrix. These materials
type monomer is described as well as the preparation are efficient recyclable catalysts for the ring-closing
of several organic-inorganic hybrid materials derived metathesis reaction of dienes and enynes, even for
from it by sol-gel processes and by anchoring to the formation of tri- and tetrasubstituted olefins.
commercial silica gel and MCM-41. The resulting
materials were treated with first and/or second gen- Keywords: catalyst immobilization; metathesis; or-
eration Grubbsꢀ catalyst to generate Hoveyda– ganic-inorganic hybrid materials; ruthenium; sol-gel
Grubbsꢀ type alkylidene ruthenium complexes cova- process
Introduction
nium alkylidenes of type 1 and 2 to the polymeric
matrix has been performed via phosphine exchange,[6]
Olefin metathesis is a mild, efficient and selective via the N-heterocyclic carbene ligand,[7] through halo-
method for the C=C bond formation, widely used by gen exchange,[8] or via alkylidene exchange (boomer-
organic chemists for the preparation of a great variety ang-type catalysts).[9] The efficiency of boomerang-
of compounds.[1] In recent years, ring closing enyne supported catalysts increases notably when Hoveyda-
metathesis has also been explored, which provides 1-
vinylcycloalkene derivatives from acyclic enynes in an
atom economical process.[2] The enormous success of
metathesis reactions during the last years is due to
the development of several well-defined metal alkyli-
denes. The second generation Grubbsꢀ ruthenium cat-
alysts[3] 1b and c (Figure 1) and specially the Hovey-
da–Grubbsꢀ catalysts[4] 2a and b (Figure 1) show en-
hanced reactivity, stability and recovery profiles com-
pared to the first generation Grubbsꢀ catalyst 1a
(Figure 1), the chelating styrenic ligands playing a
role in such improvements. Several research groups
have prepared and tested reusable metathesis cata-
lysts,[5] one of the most used recycling strategies being
the immobilization of a robust and stable alkylidene
complex on a polymeric insoluble support. Filtration
at the end of the reaction allows an easy separation of
the product and recovery of the catalyst, avoiding
time-consuming chromatography. Anchoring of ruthe- Figure 1. Ruthenium alkylidene metathesis catalysts.
Adv. Synth. Catal. 2007, 349, 1701 – 1713
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Xavier Elias et al.
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type chelating ligands are used.[10] Insoluble organic the pores. The co-gelification of a silylated monomer
polymers are the supports most frequently used, al- with TEOS would allow a higher and controllable
though anchoring to soluble poly(ethylene glycol)[10a–c] loading of the organic moiety throughout the matrix,
and some recent examples of silica-bound alkylidene which results in a supported catalyst different from
ruthenium complexes have also been described.[6b, those prepared by grafting.
7c–e,8b–d,10f,g,j,k]
In this context, silica-based inorganic polymers can
present high surface areas. Furthermore, the hybrid Results and Discussion
organic-inorganic materials formed by catalytic spe-
cies covalently anchored to silica have chemical, me- Monomer Synthesis
chanical and thermal stability superior to that of or-
ganic polymers. Most of the above-mentioned exam- The monosilylated monomer 7 used for the synthesis
ples about silica-bound catalysts refer to anchoring to of hybrid materials was prepared as summarized in
porous and non-porous silicas and to non-porous glass Scheme 1. 4-Isopropoxy-3-vinylphenol (3)[10a] was re-
monoliths. The sol-gel hydrolytic condensation[11–13] of acted with iodide 4 in anhydrous DMF at 508C in the
suitable organoalkoxysilanes is a convenient method presence of potassium carbonate to afford the pro-
to synthesize solid hybrid materials with targeted tected alcohol 5 in 70% yield. Subsequent deprotec-
properties.[14–16] Recently, we have reported[10k] the tion of 5 with tetrabutylammonium fluoride gave the
preparation and the activity as recyclable metathesis alcohol 6 in 99% yield, which was treated with com-
catalysts of bridged silsesquioxanes synthesized from mercial 3-(isocyanatopropyl)triethoxysilane in anhy-
a bis-silylated Hoveyda-type monomer via the sol-gel drous dichloromethane at room temperature to afford
process. This was the first example in the literature the desired carbamate 7 in 90% yield.
for the use of a bis-silylated ligand in a sol-gel process
for the preparation of reusable metathesis catalysts.
As our previous catalyst[10k] did not bear the classical Preparation of Hybrid Materials and Catalysts
chelating isopropoxy groups present in most of the re-
cyclable Hoveyda-type ligands, which could remain Several hybrid materials were prepared from the
the best choice for activity and recyclability, we have monosilylated carbamate 7 (Scheme 2). Co-gelifica-
performed further studies with supported catalysts de- tion with different amounts of tetraethoxysilane (5:1,
rived from a monosilylated Hoveyda-type monomer 19:1 and 40:1 as molar ratios of TEOS:7) in ethanol
featuring this bulkier group which we present in this at room temperature under nucleophilic conditions
work. Both strategies for material preparation, graft- (stoichiometric water, 1% molar of ammonium fluo-
ing and sol-gel co-gelification with TEOS, were tested ride as catalyst) afforded materials 8a–c. Co-gelifica-
for comparison. Grafting does not allow the control tion of 7 with TEOS (19:1 as molar ratio of TEOS:7)
of either the concentration of the organic groups or was also performed with dodecylamine acting both as
their distribution, which depends on the number of basic catalyst and surfactant,[17,18] giving rise to materi-
surface silanol groups, on the diffusion of reagents al 8d. On the other hand, anchoring of 7 to a commer-
through the pores channels, and on steric factors, cial silica gel[19] and to a mesostructured silica MCM-
some organic moieties remaining on the surface of 41[20] under standard conditions (in refluxing toluene
Scheme 1. Preparation of the monosilylated Hoveyda-type monomer 7.
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Recyclable Diene and Enyne Metathesis Catalysts
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Scheme 2. Preparation of hybrid silica materials 8a–f and 8dSi from 7.
for 24 h) afforded materials 8e and 8f, respectively. Fi-
A very low surface area was observed for hybrid
nally, hydrosilylation of surface hydroxy groups of material 8a (5:1). However, increasing the amount of
material 8d was achieved by heating at 1258C with TEOS in the co-gelification process led to highly
excess hexamethyldisilazane, leading to 8dSi. Capping porous materials, the corresponding BET surface area
of the silanol groups was performed in order to test if values for 8b (19:1) and 8c (40:1) being 584 and
an improved material could be obtained.
747 m2/g, respectively. The use of dodecylamine as
The materials were studied by several techniques catalyst and surfactant[17,18] gave a material 8d with
(29Si CP-MAS NMR, BET surface area measure- even a higher porosity (893 m2/g), a narrower pore
ments, p-XRD). The 29Si solid state NMR data, some size distribution and a worm-like structure observed
textural properties and the ligand loading of hybrid by transmission electron microscopy (TEM) and
materials 8 are summarized in Table 1.
powder X-ray diffraction (p-XRD) (Figure 3). The
29Si CP-MAS NMR of 8b–e confirmed the covalent grafted material 8f has a much higher BET surface
bonding of the organic moiety to the matrix by the area (915 m2/g) and narrower pore size distribution
appearance of T2 and T3 signals due to the ligand in (20–35 Š) than 8e (324 m2/g, 30–150 Š) as expected.
addition of the characteristic Q3 and Q4 signals due to The ordered hexagonal structure characteristic of
the condensed TEOS. The 29Si CP-MAS spectrum of MCM-41 was maintained in 8f as confirmed by TEM.
8dSi showed a signal around 11.9 ppm corresponding
to the SiMe3 unit and the intensity of the Q absorp- loading amount of organic ligand than materials 8e–f
tion (À103.1) decreased considerably (Figure 2).
The materials 8a–d prepared by sol-gel show higher
3
À
made by anchorage (Table 1). Moreover, the sol-gel
Table 1. Some analytical and textural data of hybrid materials 8.
8
29Si CP MAS NMR
SBET [m2 gÀ1]
Pore Diam. (Š)
mmol 8 [g]
Me3SiO
T1
T2
T3
Q2
Q3
Q4
8a
8b
8c
8d
8dSi
8e
-
-
-
-
-
-
-
-
-
-
-
-
-
<1
584
747
893
-
37
44
18–23
1.21
À59.3
À59.3
À53.7
À65.4
À65.6
À65.0
À66.7
À90.9
À90.9
-
À101.0
À100.9
À100.7
À103.1
-101.0
À108.7
À110.0
À109.3
À111.2
-110.1
0.485
0.349
0.557
11.9
-48.8
-56.0
-91.6
324
915
30-150
20–35
0.271
0.164
8f
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Figure 3. Powder X-ray diffraction of material 8d.
cogelification allows a higher control of the distribu-
tion of organic ligands into the pores and throughout
the matrix. With respect to the porosity, the BET sur-
face area increases with the dilution of organic ligand
in the co-gelification process and also with the addi-
tion of surfactant, achieving for 8d a value similar to
that of 8f, material derived from grafting to meso-
structured MCM-41. A narrower pore size distribu-
tion is obtained in organized materials (8d, 8f) as ex-
pected (Table 1).
The materials 8b–f and 8dSi were charged with the
metal by treatment with the second generation
Grubbsꢀ catalyst 1b (0.95–1.06 equivs.) in refluxing an-
hydrous and degassed dichloromethane for 24 h
(Scheme 3). Materials 8a, 8e and 8f were also treated
with the first generation Grubbsꢀ catalyst 1a following
Figure 2. Solid state CP-MAS NMR: a) 29Si of 8d and b) 29Si
of 8dSi.
Scheme 3. Preparation of ruthenium heterogeneous catalysts 9a–f, 9dSi, 10a, 10e and 10f from the corresponding materials
8.
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Recyclable Diene and Enyne Metathesis Catalysts
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an analogous procedure (Scheme 3). Ruthenium con-
tents in materials 9b–f, 9dSi, 10a, 10e and 10f were
determined by inductively coupled plasma (ICP) anal-
ysis, the results being summarized in Table 2.
Table 2. Ruthenium contents in hybrid materials 9 and 10.
9
% Ru
mmol Ru [g]
9b
9c
9d
9dSi
9e
1.34
1.41
2.43
1.71
0.84
1.19
0.37
0.90
1.44
0.133
0.139
0.240
0.169
0.083
0.118
0.036
0.089
0.142
9f
10a
10e
10f
Assay of Supported Catalysts in Diene and Enyne
Ring-Closing Metathesis Reactions
Supported catalysts 9b–f, 9dSi, 10a, 10e and 10f have
been tested in the ring-closing metathesis reaction of
N,N-diallyl-4-methylbenzenesulfonamide (11)[21] to
give 1-[(4-methylphenyl)sulfonyl]-2,5-dihydro-1H-pyr-
role (12)[21] (Scheme 4). In all cases the reaction was
performed in dichloromethane (0.05M for 11) at
room temperature under an inert atmosphere, using a
3.5% molar concentration of catalyst for the times in-
dicated in Table 3 (the disappearance of 11 was moni-
tored by GC). Filtration and evaporation of the sol-
vent afforded pure 12, together with small amounts of
11 in some cases (the molar ratio 12/11 was deter-
mined by 1H NMR). Heterogeneous catalysts were
reused directly in the next run, five cycles being per-
formed for each catalyst. The reaction times were
maintained the same in order to follow the efficiency
of the catalyst upon recycling.
Scheme 4. Diene and enyne metathesis reactions tested with
recyclable catalysts 9 and 10.
As we see in Table 3, the activity of catalysts 9 was second generation Grubbsꢀ complex 1b. For this
clearly superior to that of catalysts 10, as expected. reason, treatment of the remaining materials 8 with
Thus, faster reactions and better recyclability were the first generation Grubbsꢀ complex 1a was not per-
obtained with supported catalysts 9 prepared with the formed.
Table 3. Results for the RCM of 11 to 12 with supported catalysts 9 and 10.
Run
9b
9c
9d
9dSi
9e
9f
10a[a]
10e
10f
t
Conv.
t
Conv.
t
Conv.
t
Conv.
t
Conv.
t
Conv.
t
Conv.
t
Conv.
t
Conv.
[h] [%]
[h] [%]
[h] [%]
[h] [%]
[h] [%]
[h] [%]
[h] [%]
[h] [%]
[h] [%]
1
2
3
4
5
6
5
5
5
5
5
97
>98
97
95
91
3
3
3
3
3
6
96
1.5 94
1.5 96
1.5 91
1.5 83
1.5 72
6
6
6
6
6
97
>98
97
90
84
3
3
3
3
3
4
96
93
96
85
73
90
4
4
4
4
4
97
95
90
84
72
16 97
16 96
16 89
16 78
16 60
24 94
24 93
24 94
24 88
24 80
17 >98
16 >98
16 94
16 77
16 51
>98
>98
>98
96
24 93
95
4
90
24 87
24 90
[a]
A 2% molar Ru was used.
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If we compare catalysts 10, 10a prepared by sol-gel refluxing dichloromethane, 2 h) with slightly decreas-
was slightly better than 10f obtained by grafting to ing conversions (96 to 92%). Blechert[10h] has used a
mesostructured MCM-41 (note that only a 2% molar soluble polymer of second generation Grubbs-Hovey-
of ruthenium was used for 10a). They react both da catalyst derivative generated by ROMP, achieving
faster than 10e but they have no clear advantage over 5 cycles with full conversions (1% molar Ru, di-
10e in terms of recyclability at the fourth and fifth chloromethane, room temperature, 1 h). But the sim-
run.
plest method to isolate and recycle the catalyst is by
In the case of catalysts 9, we observe that higher di- its immobilization in a solid insoluble support. Bar-
lution of the organic ligand in the inorganic matrix rett[9c] has anchored a second generation Grubbsꢀ cat-
improves the activity of the catalysts (9c>9b). Or- alyst to polystyrene by the alkylidene moiety and has
dered materials give also faster reactions (compare 9b described 5 cycles with decreasing conversions (100 to
and 9d with the same 19:1 ratio), although this does 42%) (2.5% molar Ru, toluene, 508C, 2 h). Nolan[9e]
À
not result in better recyclability. Silylation of the Si
has reported the same type of catalysts anchored to
OH groups of the material decreases the activity of polydivinylbenzene resins, performing 3 cycles (5%
the catalyst (slower reactions) (compare 9d and 9dSi) molar Ru, dichloromethane, room temperature, 1 h)
but it seems to improve the reusability (better yields with modest GC yields (30–38%). By anchoring a
in the fourth and fifth runs). Catalysts 9e and 9f pre- second generation Hoveyda–Grubbs catalyst to silica
pared by grafting show similar results. It is worthy of gel, Blechert[10j] reported recently 4 cycles with de-
mention that their reusability is worse than that of creasing conversions (>99% to 68%) (0.15% molar
the material 9c prepared by sol-gel.
Ru, dichloromethane, room temperature, 1 h). Bann-
As general trends, we can conclude that the activity warth[10l] performed the reaction in scCO2 (five
and recyclability of the supported catalysts are im- cycles) with several solid phase-bound Hoveyda-type
proved with a higher dilution of the organic ligand in catalysts (2.5% of catalyst, 408C, 150 bar, 24 h) with
the matrix in the sol-gel derived materials and also conversions going from 95% to 84% and 93 to 57%
with the introduction of some ordering in these mate- in the best cases. Grela[10m] has very recently achieved
rials, both factors increasing the BET surface area a non-covalent immobilization of Hoveyda–Grubbs
and facilitating the diffusion of the reactants. Sol-gel catalyst to polymeric phases by means of electrostatic
derived materials give better catalytic properties than binding, performing five cycles of the reaction with
materials derived from grafting, which must be more gradual loss of activity (5% of catalyst, dichlorome-
related to the intrinsic structural differences between thane, room temperature, 24 h; from 85% to 52%).
both types of materials than to the properties such as We have recently described[10k] several recyclable or-
surface area, pore size and pore size distribution.
ganic-inorganic hybrid materials prepared from a bis-
The ring-closing metathesis reaction to afford 12 silylated Hoveyda-type monomer by sol-gel metholo-
has been performed in the literature with several re- gies. Our conditions[10k] for the preparation of 12 were
cyclable immobilized catalyst types under different milder than those used in most of the precedent
conditions.[9c,e,10a,h,j–m,22] Mauduit[22a] used imidazolium- works (percentage of catalyst and/or reaction temper-
tagged first and second generation Grubbsꢀ Ru com- ature and/or reaction time), achieving a recyclability
plexes in ionic liquid as immobilizing solvent (2.5% better than in most of the aforementioned solid in-
molar Ru, BMIM.PF6, 608C, 45 min) obtaining full soluble supports (3.5% molar Ru, dichloromethane,
conversions up to 5 cycles. In a similar work, Yao[21b] room temperature, 1.5 h, five cycles from >98 to
(1% molar Ru, BMIM·PF6-CH2Cl2 1:9, 458C, 1 h, 66%). Our present results with materials 9 offer a
0.2M) achieved 17 cycles with conversions from clear improvement in terms of recyclability. In analo-
>98% to 90%. Gibson[22c] reported the encapsulation gous conditions (3.5% molar Ru, dichloromethane,
of second generation Grubbsꢀ catalyst in polystyrene room temperature, 1.5 h) we obtain a 72% conversion
(2.5% molar Ru, water/methanol 4:1, 508C, 1.5 h) af- in the fifth run with material 9d. In other cases, al-
fording 4 cycles with decreasing yields (92% to though lower reaction rates are observed, the reusa-
40%). Curran[22d] performed the reaction with fluo- bility is better (in the fifth run we achieved 96% con-
rous versions of first and second generation Grubbs– version in 3 h for 9c and 91% conversion in 5 h for
Hoveyda catalysts (5% molar Ru, refluxing dichloro- 9b). Although some recycling strategies involving
methane, 2 h) achieving 7 cycles with full conversions the reaction performed under homogeneous condi-
or 5 cycles with conversions up to 94%. Recently, tions[10h,22a,b,d,e] remain superior, the advantage of sim-
Lee[22e] has attached a second generation Grubbs– plicity in the separation procedure must be taken into
Hoveyda catalyst on gold clusters, achieving 4 cycles account.
with full conversions (5% molar Ru, dichlorome-
Then, we turned our attention to more challenging
thane, 408C, 1.5 h). Yao[10a] described soluble poly- dienes, 13 and 15, from which the corresponding tri-
mers of first generation Grubbs–Hoveyda catalyst substituted and tetrasubstituted olefins, 14 and 16,
anchored to PEG used up to 3 cycles (5% molar Ru, could be obtained (Scheme 4). Complete conversion
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of 13 to 3-methyl-1-[(4-methylphenyl)sulfonyl]-2,5-di- cycles. Structuring of the hybrid material seems to
hydro-1H-pyrrole, 14, with second generation Grubbsꢀ offer an advantage in the recycling for a challenging
catalyst 1b under homogeneous conditions (3.5% tetrasubstituted olefin.
molar, 0.05M of 13, dichloromethane, room tempera-
We should mention that very few reports appear in
ture) required less than 3 h. This transformation was the literature about this challenging ring closing meta-
only tested with the supported catalyst 9c, which had thesis reaction. Grela[10e] found a 45% conversion in a
shown a very good performance for the diene 11. Ex- homogeneous process with a modified Hoveyda–
cellent results were obtained, outlined in Scheme 4 Grubbs second generation catalyst (5% molar Ru, re-
and Table 4. Complete conversions were achieved in fluxing dichloromethane, 16 h), describing also a
7 h with only a slight decrease in activity at the fifth failed attempt to obtain 16 with a supported catalyst
cycle (93% conversion).
(0% conversion in the second cycle, 5% molar Ru,
refluxing dichloromethane, 16 h). Mauduit[22a] de-
scribes this reaction using imidazolium-tagged ruthe-
nium complexes in room temperature ionic liquids,
but no recycling could be achieved (5% molar Ru,
BMI·PF6/toluene, 608C, 7 h, 65% conversion in the
first cycle, 0% conversion in the second cycle). We
have recently reported[10k] this reaction with silica-
based hybrid materials derived from a bis-silylated
Hoveyda-type monomer, with very poor conversions
at the second cycle. The use of monomer 7 featuring
an isopropoxy group improves, as we have mentioned
before, the recyclability properties of the sol-gel de-
rived materials. Thus, our results with tetrasubstituted
olefin 15 constitute the first successful example of re-
Table 4. Results for the RCM of 13 to 14 with catalyst 9c.
Run
9c
t [h]
Conv. [%]
1
2
3
4
5
6
7
7
7
7
7
15
94
>98
>98
96
93
98
Only Mauduit[22a] has assayed this reaction with im- cycling for the obtention of 16. Few reports can be
mobilized catalysts using imidazolium-tagged Hovey- found about the recyclability of ruthenium catalysts in
da-type complexes in room temperature ionic liquids the preparation of other tetrasubstituted alkenes, such
as solvents and immobilizing agents (5% molar Ru, as (Z)-4,5-dimethyl-1-tosyl-2,3,6,7-tetrahydro-1H-aze-
BMI·NTf2, 408C, 4 h; 6 runs, from 98 to 50% conver- pine[10b,22b] and diethyl 3,4-dimethylcyclopent-3-ene-
sion in the best case, 74% at the fifth run). The reusa- 1,1-dicarboxylate.[9e] For the first substrate, Yao[10b] de-
bility of our catalyst 9c is superior and the work-up scribed 3 cycles using a soluble second generation
very advantageous.
Grubbs–Hoveyda carbene complex immobilized on
In our hands, treatment of N,N-bis(2-methylallyl)-4- poly(ethylene glycol) (5% molar Ru, 0.4M, refluxing
methylbenzenesulfonamide (15) with second genera- dichloromethane, 18 h, 82% conversion at the third
tion Grubbsꢀ catalyst 1b under homogeneous condi- cycle) and the same author[22b] performed 2 cycles
tions (3.5% molar Ru, 0.05M of 15, toluene, 808C, with an imidazolium-tagged second generation Hov-
7 h) gave 90% conversion to 3,4-dimethyl-1-[(4-meth- eyda–Grubbs catalyst (4% molar Ru, BMIM·PF6-
ylphenyl)sulfonyl]-2,5-dihydro-1H-pyrrole (16). Sup- CH2Cl2, 1:1, 458C, 16 h, 79% and 78% conversion).
ported catalysts 9c and 9d were also assayed under For the second substrate, Nolan[9e] achieved 4 cycles
analogous conditions. Catalyst 9c afforded an 88% with modest yields with a second generation Grubbsꢀ
conversion (1H NMR) after 24 h (Scheme 4 and catalyst anchored to
a cross-linked polystyrene
Table 5). The conversion decreased to 29% after the through the alkylidene ligand (5% molar Ru, toluene,
same reaction time in the second cycle. The catalytic 808C, 3 h, GC yields between 36 and 22%).
material 9d provided better results, giving complete
On the other hand, the ring-closing enyne metathe-
conversion after 22 h. The attempted recycling gave sis was successfully performed on 1-allyloxy-1,1-di-
93 and 31% conversion in the second and third phenyl-2-propyne (17) to give 2,2-diphenyl-3-vinyl-
2,5-dihydrofuran (18) with our heterogeneous cata-
lysts 9c, 9d and 9dSi (Scheme 4 and Table 6). Good
Table 5. Results for the RCM of 15 to 16 with catalysts 9c
conversions (ca. 100%) were obtained in short reac-
and 9d.
tion times (2 to 4.5 h) with 3.5% molar of catalyst in
anhydrous dichloromethane (0.05M of 17) at room
temperature, and up to three or five cycles were per-
formed with only slightly decreasing conversions.
Under analogous homogeneous conditions with the
second generation Grubbsꢀ catalyst 1b we obtained
full conversion in 1 h.
Run
9c
Conv. [%]
9d
Conv. [%]
t [h]
t [h]
1
2
3
24
24
–
88
29
–
22
22
22
>98
93
31
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Table 6. Results for the RCM of 17 to 18 with catalysts 9c,
9d and 9dSi.
ration of several hybrid organic-inorganic materials 8
by sol-gel co-gelification with TEOS and by anchor-
age to commercial and mesostructured MCM-41, then
the obtention of the corresponding Grubbs–Hoveyda-
type ruthenium complexes 9 and 10, and their evalua-
tion as recyclable catalysts in the ring-closing meta-
thesis reactions of dienes 11, 13 and 15 and enyne 17.
As expected, supported catalysts 9 prepared from the
second generation Grubbsꢀ complex 1b gave much
higher reaction rates than catalysts 10 prepared from
the first generation Grubbsꢀ complex 1a in the RCM
on N,N-diallyl-4-methylbenzenesulfonamide (13).
Run
9c
9d
9dSi
t [h] Conv. [%] t [h] Conv. [%] t [h] Conv. [%]
1
2
3
4
5
6
4.5
4.5
4.5
4.5
4.5
24
>98
81
92
93
90
3
3
3
3
3
>98
94
92
91
88
2
2
2
>98
>98
>98
100
This enyne ring-closing metathesis process has been They offer milder conditions and better recyclability
described in the literature[23,24] using several catalysts than other previous works based on catalysts anch-
and homogeneous conditions, but there is no report ored to insoluble solid supports. The RCM on more
about recycling and about using polymer-supported challenging substrates, N-allyl-N-(2-methylallyl)-4-
catalysts for the obtention of 18 except our own methylbenzenesulfonamide (13). and N,N-bis(2-meth-
recent work[10k] and the report of Grela,[10m] which do ylallyl)-4-methylbenzenesulfonamide (15) gave rise to
not mention the recycling with this enyne substrate.
trisubstituted and tetrasubstituted alkenes 14 and 16,
A blank test suggested by one referee has been per- respectively, good yields and recyclability being ach-
formed with catalyst 9e in the RCM reaction of diene ieved for the trisubstituted olefin. Two very successful
11. A suspension of 9e in anhydrous dichloromethane runs have been performed for the tetrasubstituted
was stirred at room temperature under inert atmos- one, constituting the first report of recycling for this
phere for three hours. Then the solid was filtered and substrate. Our materials are also good recyclable cata-
11 was added to the filtrate. The solution was stirred lysts for the ring-closing enyne metathesis performed
at room temperature under nitrogen atmosphere for on 1-allyloxy-1,1-diphenyl-2-propyne (17). This is the
3 h and the solvent was evaporated. The 1H NMR second case described in the literature about recycling
analysis of the residue showed a mixture of 11 and 12 in this ring-closing enyne metathesis reaction, the first
in a molar ratio 97:3. This small percentage of conver- one being recently reported by us.[10k] In all cases, ma-
sion must be due to a homogeneous process derived terials prepared from sol-gel are superior to those
from some leaching of the heterogeneous catalyst. coming from anchorage to commercial silica or meso-
However, we must take into account that, due to the structured MCM-41. Further investigations are under-
release-return mechanism[9,10] operating in these Hov- way with other structurally modified ligands in order
eyda–Grubbs boomerang-type catalysts, the reaction to get improved activity and reusability.
takes place in homogeneous phase with the soluble
ruthenium carbenic species released from the support-
ed catalyst after the addition of the substrate, which
are then recaptured by the polymer. In this respect,
Experimental Section
another experiment was performed with catalyst 9b in
the RCM reaction of the same diene 11. A mixture of
11 (0.132 mmol) and 9b (0.00456 mmol Ru) in anhy-
drous dichloromethane (2.5 mL) was stirred at room
temperature under inert atmosphere for 15 min. The
insoluble catalyst was filtered under nitrogen and the
resulting filtrate containing an 18% of 12 (1H NMR
monitoring) was left under stirring at room tempera-
General Remarks
When required, experiments were carried out with standard
high-vacuum and Schlenk techniques. Solvents were dried
and distilled just before use. Ammonium fluoride and N,N-
bis(trimethylsilyl)amine were purchased from Aldrich, 3-
(triethoxysilyl)propyl isocyanate was purchased from Lan-
caster, tetraethyl orthosilicate, potassium tert-butoxide and
tetrabutylammonium fluoride were purchased from Acros.
ture for 5 h. The solvent was evaporated and the resi- The second generation Grubbsꢀ catalyst has been purchased
1
from Aldrich and also from Acros. IR data were obtained in
the following spectrophotometer: Bruker Tensor 27 with
ATR Golden Gate. The solution NMR spectra were record-
ed on a Bruker AC-250 (1H and 13C). Chemical shifts (d,
ppm) were referenced to Me4Si (1H, 13C). The abbreviations
used are s for singlet, d for doublet, dd for double doublet, t
for triplet, q for quartet, quint for quintuplet, sept for septet
and m for multiplet. The CP-MAS 29Si solid state NMR
spectra were recorded on a Bruker FT-AM 400. The repeti-
tion time was 5 seconds with contact times of 5 milliseconds.
due was analysed by H NMR, showing a 23% of 12.
The small increase in the conversion is due to the ex-
pected soluble catalytic species remaining in solution
after the filtration.
Conclusions
In summary, we have described the synthesis of a
monosilylated Hoveyda-type monomer 7, the prepa- Surface areas were determined by Brunauer-Emmett-Teller
1708
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Adv. Synth. Catal. 2007, 349, 1701 – 1713

Recyclable Diene and Enyne Metathesis Catalysts
FULL PAPERS
(BET) method on a Micromeritics Gemini III 2375 analyzer,
and the average pore diameter was calculated by the BJH
method. ESI mass spectra were acquired using a Navigator
quadrupole instrument, operating in the positive ion mode
(ES+) at a probe tip voltage of 3 kV. HR-MS have been de-
termined at SCAI-Unidad de Espectrometría de Masas at
the Universidad de Córdoba. Elemental analysis have been
performed at the Servei dꢀAnàlisi Química of the Universi-
tat Autònoma de Barcelona or at the Serveis Científico-T›c-
nics of the Universitat de Barcelona. The content of rutheni-
um was determined at the Serveis Científico-T›cnics of the
Universitat de Barcelona by inductively coupled plasma
(ICP) techniques.
performed. The combined organic layers were washed with
water (2”40 mL) and saturated aqueous NaCl (30 mL),
dried over anhydrous Na2SO4 and concentrated under
vacuum to afford 6 as a yellow oil; yield: 1.55 g (99%).
1H NMR (250 MHz, CDCl3): d=7.11–7.00 (m, 2H), 6.85 (d,
1H, J=8.9 Hz), 6.78 (dd, 1H, J=8.9, 2.9 Hz), 5.73 (dd, 1H,
J=17.7, 1.4 Hz), 5.26 (1H, J=11.1, 1.4 Hz), 4.41 (sept, 1H,
J=6.1 Hz), 4.13 (t, 2H, J=5.9 Hz), 3.86 (t, 2H, J=5.9 Hz),
2.23 (s, 1H), 2.04 (quint, 2H, J=5.9 Hz), 1.33 (d, 6H, J=
6.1 Hz); 13C NMR (62.5 MHz, CDCl3): d=152.9, 149.4,
131.6, 129.1, 116.8, 114.6, 113.9, 111.8, 72.1, 66.1, 60.2, 31.9,
22.0; IR (ATR): n=3334, 2973, 1575, 1488, 1425, 1383, 1282,
1207, 1108, 1058, 995, 954, 907, 851, 807 cmÀ1; MS: m/z=236
(M+) (21), 194 (38), 136 (100), 107 (21), 91 (5), 77 (12), 65
(4), 43 (12), 41 (12); HR-MS: m/z=236.1412 (calcd. for
C14H20O3: 236.1395).
1-(tert-Butyldimethylsiloxy)-3-iodopropane (4)[25] was pre-
pared in two steps from 3-chloro-1-propanol as reported.[26]
Mesostructured silica MCM-41 was prepared following the
standard procedure.[20] Methyltriphenylphosphonium iodide
was synthesized from methyl iodide and triphenylphosphine.
4-Isopropoxy-3-vinylphenol, 3, was prepared as reported.[10a]
The dienes 11 and 15, and enyne 17 were prepared as previ-
ously described by us.[10k] The diene 13[27] was synthesized
from N-allyl-p-toluenesulfonamide[28] and 3-bromo-2-
methyl-1-propene.
Synthesis of O-{3-[(3-vinyl-4-isopropoxy)phenoxy]-
propyl} N-(3-Triethoxysilylpropyl) Carbamate (7)
Freshly distilled 3-(triethoxysilyl)propyl isocyanate (1.9 mL,
0.99 gmLÀ1, 7.22 mmol) was added dropwise via syringe
under argon to 6 (1.18 g, 4.99 mmol) in anhydrous dichloro-
methane (7 mL). The mixture was stirred under argon at
room temperature for 5 days (1H NMR monitoring). The
solvent was removed under vacuum and excess isocyanate
was distilled off (1008C, 1.7 mbar). Anhydrous diethyl ether
(4 mL) was added to the residue, the solution was filtered
under nitrogen atmosphere and the solvent was evaporated,
Synthesis of 2-Isopropoxy-5-(3-tert-butyldimethyl-
siloxypropoxy)styrene (5)
Potassium carbonate (1.940 g, 14.04 mmol) was added to a
stirred solution of 4-isopropoxy-3-vinylphenol (3; 1.0 g,
5.62 mmol) and 1-(tert-butyldimethylsiloxy)-3-iodopropane
(4; 1.687 g, 5.62 mmol) in DMF (44 mL). The mixture was
stirred overnight at 408C under argon. Upon cooling at
room temperature water was added (30 mL) and the solu-
tion was extracted with petroleum ether (3”30 mL). The
combined organic layers were dried over anhydrous Na2SO4
and concentrated under vacuum. The residue was chromato-
graphed through silica gel (hexane/dichloromethane, 3:1, as
1
to give 7 as a pale yellow oil; yield: 2.17 g (90%). H NMR
(250 MHz CDCl3): d=7.03–6.98 (m, 2H), 6.82 (d, 1H, J=
8.8 Hz), 6.75 (dd, 1H, J=8.8, 2.8 Hz), 5.71 (dd, 1H, J=17.9,
1.4 Hz), 5.24 (dd, 1H, J=11.1, 1.4 Hz), 5.02 (m, 1H), 4.37
(sept, 1H, J=5.9 Hz), 4.24 (t, 2H, J=6.1 Hz), 4.01 (t, 2H,
J=6.3 Hz), 3.82 (q, 6H, J=7.0 Hz), 3.17 (apparent q , 2H,
J=6.4 Hz), 2.06 (m, 2H), 1.63 (m, 2H), 1.31 (d, 6H, J=
6.1 Hz), 1.22 (t, 9H, J=7.0 Hz), 0.63 (t, 2H, J=8.0 Hz);
13C NMR (62.5 MHz, CDCl3): d=156.3, 152.9, 149.3, 131.6,
129.1, 116.7, 114.6, 113.8, 111.7, 72.0, 64.7, 61.2, 58.1, 43.1,
28.9, 23.0, 21.9, 18.0, 7.4; IR (ATR): n=3341, 2973, 2927,
2883, 1704, 1525, 1489, 1426, 1385, 1371, 1279, 1243, 1209,
1165, 1101, 1074, 997, 953, 852, 772 cmÀ1; HR-MS: m/z=
483.2650 (calcd. for C24H41NSiO7: 483.2652).
1
eluent) to afford 5 as an oil; yield: 1.37 g (70%). H NMR
(250 MHz, CDCl3): d=7.10–6.97 (m, 2H), 6.82 (d, 1H, J=
8.8 Hz), 6.75 (dd, 1H, J=8.8, 2.8 Hz), 5.72 (dd, 1H, J=
18.0 Hz, 1.2 Hz), 5.27 (dd, 1H, J=11.25, 1.2 Hz), 4.40 (sept,
1H, J=6.1 Hz), 4.03 (t, 2H, J=6.2 Hz), 3.80 (t, 2H, J=
6.2 Hz), 1.97 (quint, 2H, J=6.2 Hz), 1.33 (d, 6H, J=
6.1 Hz), 0.93 (s, 9H), 0.09 (s, 6H); 13C NMR (62.5 MHz,
CDCl3): d=153.2, 149.1, 131.7, 129.1, 116.8, 114.5, 113.7,
111.8, 72.0, 64.8, 59.4, 32.3, 25.7, 22.0, 18.1, À5.6; IR (ATR):
n=2953, 2928, 2856, 1488, 1471, 1253, 1208, 1100, 834,
774 cmÀ1; MS: m/z=351 (M+ +1) (13), 350 (M+) (3), 293
Preparation of Hybrid Material 8a
(M+À
C
ACHTREUNG
A solution of ammonium fluoride (60 mL of a 1M solution,
0.060 mmol of fluoride, 3.33 mmol of water) and distilled
and deionized water (0.414 mL, 23 mmol) in anhydrous eth-
anol (6 mL) was added to a solution of 7 (0.483 g, 1.0 mmol)
and TEOS (1.040 g, 5.0 mmol) in anhydrous ethanol (6 mL).
The mixture was stirred manually for a minute to get a ho-
mogeneous solution and was left at room temperature with-
out stirring. Gelation ocurred after few minutes and the gel
was allowed to age for 2 days, after which it was powdered
and washed successively several times with water and then
with ethanol. The solid was dried under vacuum (10À2
mmHg, room temperature, overnight), affording 8a as a
white powder; yield: 0.620 g. SBET <1 m2 gÀ1; elemental anal-
ysis found: C 25.22, H 4.05, N 1.70, Si 24.50.
A
ACHTREUNG
96 (10), 88 (8), 73 (28), 59 (10), 43 (11).
Synthesis of 3-(4-Isopropoxy-3-vinylphenoxy)propan-
1-ol (6)
A
solution of tetrabutylammonium fluoride (4.314 g,
14 mmol) in anhydrous THF (15 mL) was added under
argon to a stirred solution of 2-isopropoxy-5-(3-tert-butyldi-
methylsiloxypropoxy)styrene (5; 2.322 g, 6.62 mmol) in an-
hydrous THF (20 mL). The mixture was stirred for 2 h at
room temperature under argon. Water was added (50 mL)
and extractions with distilled diethyl ether (3”50 mL) were
Adv. Synth. Catal. 2007, 349, 1701 – 1713
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1709

Xavier Elias et al.
FULL PAPERS
n=3444 (residual), 2962, 1717, 1492, 1095, 847, 758,
Preparation of Hybrid Material 8b
457 cmÀ1
;
29Si CP-MAS NMR: d=11.9 (Me3SiO), À66.7
(T3), À103.1 (Q3), À111.2 (Q4); elemental analysis found: C
A solution of ammonium fluoride (100 mL of a 1M solution,
0.100 mmol of fluoride, 5.56 mmol of water) and distilled
and deionized water (0.7 mL, 38.9 mmol) in anhydrous etha-
nol (5 mL) was added to a solution of 7 (0.240 g, 0.5 mmol)
and TEOS (1.997 g, 9.6 mmol) in anhydrous ethanol (5 mL).
The mixture was stirred manually for a minute to get a ho-
mogeneous solution and was left at room temperature with-
out stirring. Gelation ocurred after few minutes and the gel
was allowed to age for 5 days, after which it was powdered
and washed successively several times with water and then
with ethanol. The solid was dried under vacuum (1 mmHg,
room temperature, overnight), affording 8b as a white
powder; yield: 0.751 g. SBET =584 m2 gÀ1; IR (KBr): n=3428,
19.31, H 3.55, N 0.84.
Preparation of Hybrid Material 8e
Activated silica gel (silicagel ultrapure, 60–200 mm, 60 Š,
ref: 36006 ACROS, 4.024 g, 67.1 mmol SiO2) was added to a
solution of 7 (0.650 g, 1.34 mmol) in toluene (30 mL). The
mixture was refluxed for 24 h. The solid was filtered and
washed successively with toluene, ethyl acetate (twice) and
dichloromethane (twice), and dried under vacuum (1
mmHg, room temperature, overnight), affording 8e as a
slightly yellow powder; yield: 4.332 g. SBET =324 m2 gÀ1 29Si
;
2982, 1699, 1538, 1492, 1086, 957, 801 cmÀ1 29Si CP-MAS
;
CP-MAS NMR: d=À48.8, À56.0, À91.6, À101.0, À110.1; el-
NMR: d=À59.3 (T2), À65.4 (T3), À90.9 (Q2), À101.0 (Q3),
À108.7 (Q4); elemental analysis found: N 0.68.
emental analysis found: C 6.00, H 1.26, N 0.38.
Preparation of Hybrid Material 8f
Preparation of Hybrid Material 8c
Mesostructured MCM-41 (0.443 g, 7.38 mmol SiO2) was
added to a solution of 7 (0.0713 g, 0.148 mmol) in toluene
(20 mL). The mixture was refluxed for 24 h with a Dean–
Stark apparatus. The solid was filtered and washed with ace-
tone, then it was placed in a Soxhlet and extracted with ace-
tone for 4 h., filtered and dried under vacuum (10À2 mmHg,
room temperature, overnight), affording 8f as a white
powder; yield: 0.380 g. SBET =915 m2 gÀ1; elemental analysis
found: C 5.33, H 1.74, N 0.23, Si 37.26.
A solution of ammonium fluoride (200 mL of a 1M solution,
0.200 mmol of fluoride, 11.1 mmol of water) and distilled
and deionized water (1.0 mL, 55.6 mmol) in anhydrous etha-
nol (10 mL) was added to
a solution of 7 (0.241 g,
0.50 mmol) and TEOS (4.183 g, 20.1 mmol) in anhydrous
ethanol (10 mL). The mixture was stirred manually for a
minute to get a homogeneous solution and was left at room
temperature without stirring. Gelation ocurred after few mi-
nutes and the gel was allowed to age for 5 days, after which
it was powdered and washed successively several times with
water and then with ethanol. The solid was dried under
vacuum (1 mmHg, room temperature, overnight), affording
8c as a white powder; yield: 1.501 g. SBET =747 m2 gÀ1; IR
(KBr): n=3215, 2981, 2901, 1700, 1490, 1222, 1035, 956,
Preparation of Hybrid Catalyst 9b
Anhydrous and degassed dichloromethane (15 mL) was
added under argon to a stirred mixture of 8b (0.298 g,
0.485 mmol ligand/g, 0.145 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.128 g, 0.151 mmol, 1.05 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 10 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 9b as a green powder; yield: 0.292 g; el-
emental analysis found: C 17.80, N 1.31, Ru (ICP) 1.34.
801 cmÀ1
;
29Si CP-MAS NMR: d=À59.3 (T2), À65.6 (T3),
À90.9 (Q2), À100.9 (Q3), À110.0 (Q4); elemental analysis
found: C 11.26, H 2.55, N 0.49, Si 33.10.
Preparation of Hybrid Material 8d
A solution of dodecylamine (0.40 g, 2.16 mmol) in ethanol
(10 mL) was added to distilled and deionized water (30 mL)
and stirred for 30 min. Compound 7 (0.239 g, 0.5 mmol) and
TEOS (1.981 g, 9.62 mmol) were added. The mixture was
stirred at room temperature for 24 h. The formed solid was
filtered and left to dry at air overnight. Then it was pow-
dered and extracted with ethanol in a Soxhlet for 48 h. The
solid was washed with ethanol and dried at atmospheric
pressure, affording 8d as a white powder; yield: 0.763 g.
Preparation of Hybrid Catalyst 9c
Anhydrous and degassed dichloromethane (20 mL) was
added under argon to a stirred mixture of 8c (0.500 g,
0.349 mmol ligand/g, 0.174 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.157 g, 0.185 mmol, 1.06 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 10 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, romm temperature,
overnight) to obtain 9c as a green powder; yield: 0.491 g; el-
emental analysis found: C 14.66%, H 2.13%, N 0.87, Ru
(ICP) 1.41.
S
BET =893 m2 gÀ1; IR (KBr): n=3430, 2982, 1701, 1491, 1205,
1079, 957, 797 cmÀ1
;
29Si CP-MAS NMR: d=À53.7 (T2),
À65.0 (T3), À100.7 (Q3), À109.3 (Q4); elemental analysis
found: C 14.96, H 2.37, N 0.78, Si 28.0.
Preparation of Hybrid Material 8dSi
A suspension of 8d (0.254 g) in N,N-bis(trimethylsilyl)amine
(12 mL) was heated under argon at 1258C for 24 h. After
cooling, the solid was filtered and washed with ethanol (3
times), acetone (3 times) and diethyl ether (3 times), then it
was dried under vacuum (1 mm Hg, 708C, overnight), af-
fording 8dSi as a white powder; yield: 0.259 g; IR (KBr):
Preparation of Hybrid Catalyst 9d
Anhydrous and degassed dichloromethane (20 mL) was
added under argon to a stirred mixture of 8d (0.350 g,
0.557 mmol ligand/g, 0.195 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.162 g, 0.185 mmol, 0.95 equivs.) and
1710
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Recyclable Diene and Enyne Metathesis Catalysts
FULL PAPERS
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 10 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 9d as a green powder; yield: 0.381 g; el-
emental analysis found: C 21.73, H 3.16, N 1.38, Ru (ICP)
2.43.
Preparation of Hybrid Catalyst 10e
Anhydrous and degassed dichloromethane (12 mL) was
added under argon to a stirred mixture of 8e (0.743 g,
0.168 mmol ligand/g, 0.125 mmol) and first generation
Grubbsꢀ catalyst 1a (0.121 g, 0.150 mmol, 1.2 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 12 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 10e as a brown powder; yield: 0.691 g;
elemental analysis found: C 10.72, H 1.87, N 0.50, Si 26.6
Ru (ICP) 0.90.
Preparation of Hybrid Catalyst 9dSi
Anhydrous and degassed dichloromethane (14 mL) was
added under argon to a stirred mixture of 8dSi (0.219 g,
0.603 mmol ligand/g, 0.132 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.111 g, 0.131 mmol, 0.98 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 10 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 9dSi as a green powder; yield: 0.221 g;
elemental analysis found: C 21.37%, H 3.31%, N 1.25, Ru
(ICP) 1.71.
Preparation of Hybrid Catalyst 10f
Anhydrous and degassed dichloromethane (5 mL) was
added under argon to a stirred mixture of 8f (0.170 g,
0.164 mmol ligand/g, 0.028 mmol) and first generation
Grubbsꢀ catalyst 1a (0.028 g, 0.034 mmol, 1.2 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 5 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 10f as a brown powder; yield: 0.156 g;
elemental analysis found: C 10.48, H 2.24, N 0.27, Si 36.27
Ru (ICP) 1.44.
Preparation of Hybrid Catalyst 9e
Anhydrous and degassed dichloromethane (7.5 mL) was
added under argon to a stirred mixture of 8e (0.386 g,
0.271 mmol ligand/g, 0.105 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.088 g, 0.103 mmol, 0.98 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 5 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 9e as a green powder; yield: 0.367 g; el-
emental analysis found: C 10.26, H 1.62, N 0.63, Si 34.5, Ru
(ICP) 0.84.
Ring-Closing Metathesis Reaction on N,N-Diallyl-4-
methylbenzenesulfonamide (11) with Supported
Catalysts 9 and 10. Synthesis of 1-[(4-Methylphenyl)-
sulfonyl]-2,5-dihydro-1H-pyrrole (12). Typical
Procedure
A solution of 11 (0.1004 g, 0.399 mmol) in anhydrous and
degassed dichloromethane (8 mL) was added under nitrogen
to 9b (0.1051 g, 0.133 mmol Ru/g, 0.0140 mmol Ru) and the
mixture was stirred under argon at room temperature for
5 h (GC monitoring). The mixture was filtered under nitro-
gen atmosphere with a cannula and the solid was washed 4
times with 8 mL portions of anhydrous dichloromethane.
The combined filtrates were evaporated to yield 12[21]
Preparation of Hybrid Catalyst 9f
Anhydrous and degassed dichloromethane (4.5 mL) was
added under argon to a stirred mixture of 8f (0.126 g,
0.164 mmol ligand/g, 0.0207 mmol) and Grubbsꢀ second gen-
eration catalyst 1b (0.018 g, 0.021 mmol, 1.02 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 5 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 9f as a green powder; yield: 0.117 g; el-
emental analysis found: C 9.78, H 1.82, N 0.52, Ru (ICP)
1.19.
1
(0.084 g, the molar ratio 12/11 by H NMR was 32.7/1, 97%
conversion). The solid catalyst 9b was dried and reused in
the next run.
The same conditions were adopted for the other catalysts
9c–d, 9dSi and also for catalysts 10a, 10e and 10f, except the
reaction times that are summarized in Table 3 together with
the attained conversions.
Ring-Closing Metathesis Reaction on N-Allyl-N-2-
methylallyl-4-methylbenzenesulfonamide (13) with
Supported Catalyst 9c. Synthesis of 3-Methyl-1-[(4-
methylphenyl)sulfonyl]-2,5-dihydro-1H-pyrrole (14)
Preparation of Hybrid Catalyst 10a
Anhydrous and degassed dichloromethane (20 mL) was
added under argon to a stirred mixture of 8a (0.195 g,
1.21 mmol ligand/g, 0.161 mmol) and first generation
Grubbsꢀ catalyst 1a (0.153 g, 0.186 mmol, 1.15 equivs.) and
the mixture was refluxed under argon for 24 h. The solid
was filtered, washed several times with portions of 10 mL of
anhydrous dichloromethane until the filtrate had no color,
and dried under vacuum (1 mm Hg, room temperature,
overnight) to obtain 10a as a brown powder; yield: 0.155 g;
elemental analysis found: C 27.55, H 3.92, N 1.94, Si 23.1
Ru (ICP) 0.37.
A solution of 13 (0.0535 g, 0.202 mmol) in anhydrous and
degassed dichloromethane (4 mL) was added under nitrogen
to 9c (0.0508 g, 0.139 mmol Ru/g, 0.00706 mmol Ru) and the
mixture was stirred under argon at room temperature for
7 h (GC monitoring). The mixture was filtered under nitro-
gen atmosphere with a cannula and the solid was washed 4
times with 4 mL portions of anhydrous dichloromethane.
The combined filtrates were evaporated to yield 14[29]
Adv. Synth. Catal. 2007, 349, 1701 – 1713
ꢁ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
1711

Xavier Elias et al.
FULL PAPERS
(0.0466 g, the molar ratio 14/13 by 1H NMR was 16.1/1,
94% conversion). The solid catalyst 9c was dried and reused
in the next run.
Angew. Chem. Int. Ed. Engl. 1995, 34, 1833; c) M.
Schuster, S. Blechert, Angew. Chem. Int. Ed. Engl.
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Maier, Angew. Chem. Int. Ed. 2000, 39, 2073; j) A.
Fürstner, Angew. Chem. Int. Ed. 2000, 39, 3012; k) R.
Roy, S. K. Das, Chem. Commun. 2000, 519; l) M. R.
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Trnka, R. H. Grubbs, Acc. Chem. Res. 2001, 34, 18;
n) A. H. Hoveyda, R. R. Schrock, Chem. Eur. J. 2001,
7, 945; o) F. X. Felpin, J. Lebreton, Eur. J. Org. Chem.
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P. R. Hanson, Chem. Rev. 2004, 104, 2239; q) A. Dei-
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Astruc, New. J. Chem. 2005, 29, 42; u) J. C. Conrad,
D. E. Fogg, Current Org. Chem. 2006, 10, 185.
Ring-Closing Metathesis Reaction on N,N-Bis(2-
methylallyl)-4-methylbenzenesulfonamide (15) with
Supported Catalysts 9. Synthesis of 3,4-Dimethyl-1-
[(4-methylphenyl)sulfonyl]-2,5-dihydro-1H-pyrrole
(16). Typical Procedure
A solution of 15 (0.0996 g, 0.356 mmol) in anhydrous and
degassed toluene (7 mL) was added under nitrogen to 9d
(0.052 g, 0.240 mmol Ru/g, 0.0125 mmol Ru) and the mix-
ture was stirred under argon at 808C for 22 h (GC monitor-
ing). The mixture was filtered under nitrogen atmosphere
with a cannula and the solid was washed 4 times with 7 mL
portions of anhydrous dichloromethane. The combined fil-
trates were evaporated to yield 16 (0.0862 g, the molar ratio
16/15 by 1H NMR was 66.7/1,>98% conversion). 1H and
13C NMR of 16 were coincident with that described for this
compound in the literature.[30] The solid catalyst 9d was
dried and reused in the next run.
The same conditions were adopted for catalyst 9c except
the reaction time (see Table 5).
[2] For reviews on enyne metathesis and their use in or-
ganic synthesis: a) M. Mori, Top. Organomet. Chem.
1998, 1, 133; b) C. S. Poulsen, R. Madsen, Synthesis
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[3] a) M. Scholl, S. Ding, C. W. Lee, R. H. Grubbs, Org.
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Ring-Closing Metathesis Reaction on 1-Allyloxy-1,1-
diphenyl-2-propyne (17) with Supported Catalysts 9.
Synthesis of 2,2-Diphenyl-3-vinyl-2,5-dihydrofuran
(18). Typical Procedure
A solution of 17 (0.076 g, 0.306 mmol) in anhydrous and de-
gassed dichloromethane (6 mL) was added under nitrogen
to 9c (0.0769 g, 0.139 mmol Ru/g, 0.0107 mmol Ru) and the
mixture was stirred under argon at room temperature for
4.5 h (GC monitoring). The mixture was filtered under ni-
trogen atmosphere with a cannula and the solid was washed
4 times with 6 mL portions of anhydrous dichloromethane.
The combined filtrates were evaporated to yield 18
(0.0732 g, the molar ratio 18/17 by 1H NMR was 81.2/1,
>98% conversion), whose spectroscopic data were coinci-
dent with that reported in the literature.[23] The solid catalyst
9c was dried and reused in the next run.
[4] a) J. S. Kingsbury, J. P. A. Harrity, P. J. Bonitatebus Jr,
A. H. Hoveyda, J. Am. Chem. Soc. 1999, 121, 791;
b) S. B. Garber, J. S. Kingsbury, B. L. Gray, A. H. Hov-
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The same conditions were adopted for the other catalysts
9d and 9dSi except the reaction times (see Table 4).
[5] See the review article and references cited therein:
M. R. Buchmeiser, New. J. Chem. 2004, 28, 549.
Acknowledgements
[6] a) S. T. Nguyen, R. H. Grubbs; J. Organomet. Chem.
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Financial support from the Ministry of Science and Technolo-
gy of Spain, Generalitat de Catalunya and Universitat Autòn-
oma de Barcelona (Projects 2002BQU-04002, CTQ2005–
01254/BQU and CTQ2006–04204/BQU, SGR2001–00181,
SGR2005–00305, PNL2005–10), from the French Ministry of
Research and Technology and from the CNRS is gratefully
acknowledged.
[7] a) S. C. Schürer, S. Gessler, N. Buschmann, S. Blechert,
Angew. Chem. Int. Ed. 2000, 39, 3898; b) S. Randl, N.
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