Use of immobilized molybdenum- and tungsten-containing catalysts in olefin cross metathesis

Abstract

Method of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising step (i): (i) reacting the first olefin with the second olefin in the presence of a silica supported Mo- or W-alkylidene catalyst, wherein the first olefin and the second olefin are different from one another.

Claims

1. A method of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising step (i): (i) reacting the first olefin with the second olefin in the presence of a silica supported Mo-alkylidene or W-alkylidene catalyst, wherein the catalyst is of formula I ##STR00002## wherein M is W or Mo; R.sup.1 is H, aryl, heteroaryl, alkyl, or heteroalkyl, optionally substituted, respectively; R.sup.2 and R.sup.3 can be the same or different and are alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, or heteroaryl, optionally substituted, respectively, or hydrogen; R.sup.5 is a residue R.sup.6X, wherein R.sup.6 is alkyl, aryl, heteroalkyl, heteroaryl, optionally substituted, respectively; (R.sup.7, R.sup.8, R.sup.9)Si; wherein R.sup.7, R.sup.8, R.sup.9 are independently alkyl, alkoxy, phenyl or phenoxy, optionally substituted, respectively; (R.sup.10, R.sup.11, R.sup.12)C, wherein R.sup.10, R.sup.11, R.sup.12 are independently phenyl, alkyl, optionally substituted, respectively; XO, S, or NR.sup.13, wherein R.sup.13 is H; or alkyl or aryl, optionally substituted, respectively; or R.sup.5 is R.sup.6CONR.sup.13, wherein R.sup.6 and NR.sup.13 have the meaning as defined above, or wherein R.sup.6 and R.sup.13 taken together form a carbon chain having from 2 to 6 carbon atoms; or R.sup.5 is an optionally substituted 4 to 8 membered N-containing ring, wherein N is linked to M; and R.sup.4 is a residue OSi(O).sub.3, and represents silica to which M is linked forming a M-OSi(O).sub.3 moiety, and wherein the first olefin and the second olefin are different from one another.

2. The method of claim 1, wherein (a) the first olefin is a cyclic olefin and the second olefin is a cyclic olefin; or (b) the first olefin is a cyclic olefin and the second olefin is a non-cyclic olefin; or (c) the first olefin is a non-cyclic olefin and the second olefin is a non-cyclic olefin.

3. The method of claim 1, wherein the first olefin or the second olefin is a C.sub.4-C.sub.30 olefin.

4. The method of claim 1, wherein the first olefin has an internal olefinic double bond and the second olefin is ethylene.

5. The method of claim 1, wherein R.sup.1 is aryl or adamant-1-yl, optionally substituted, respectively; R.sup.2 is C(CH.sub.3).sub.2C.sub.6H.sub.5 or C(CH.sub.3).sub.3; R.sup.3 is H; R.sup.5 is a residue R.sup.6X, wherein XO and R.sup.6 is phenyl or phenyl substituted with up to five substituents independently selected from alkyl; alkoxy; phenoxy, phenyl, optionally substituted, respectively; or halogen; or XS and R.sup.6 is phenyl or phenyl substituted with up to five substituents independently selected from alkyl; alkoxy; phenoxy, phenyl, optionally substituted, respectively; or halogen; or XO and R.sup.6 is triphenylsilyl or triphenoxysilyl, optionally substituted, respectively; or tri(C.sub.1-C.sub.4 alkyl)silyl or tri(C.sub.1-C.sub.4 alkoxy)silyl; XO and R.sup.6 is triphenylmethyl, optionally substituted; or XO and R.sup.6 is 9-phenyl-fluorene-9-yl; or XO and R.sup.6 is 2-phenyl-1,1,1,3,3,3-hexafluoro-prop-2-yl [(C.sub.6H.sub.5)(CF.sub.3).sub.2C]; or XO and R.sup.6 is t-butyl, optionally substituted with one or more F groups.

6. The method of claim 1, wherein R.sup.1 is phenyl or phenyl substituted with up to five substituents independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, CF.sub.3, F, Cl, Br or phenyl or phenoxy, optionally substituted, respectively; and XO and R.sup.6 is phenyl substituted with up to five substituents independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, phenoxy, phenyl, halogen; or XS and R.sup.6 is phenyl substituted with up to five substituents independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, phenoxy, phenyl, halogen; or XO and R.sup.6 is triphenylsilyl, triphenoxysilyl, tri(C.sub.1-C.sub.4 alkyl)silyl or tri(C.sub.1-C.sub.4 alkoxy)silyl; or XO and R.sup.6 is t-butyl or (CF.sub.3)(CH.sub.3).sub.2C, (CF.sub.3).sub.2(CH.sub.3)C, (CF.sub.3).sub.3C or (C.sub.6H.sub.5)(CF.sub.3).sub.2C; or R.sup.5 is pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl.

7. The method of claim 1, wherein R.sup.1 is an electron donating group and R.sup.5 is an electron withdrawing group.

8. The method of claim 7, wherein R.sup.1=phenyl substituted with up to five substituents independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, phenyl, or phenoxy; R.sup.2 is C(CH.sub.3).sub.2C.sub.6H.sub.5 or C(CH.sub.3).sub.3; R.sup.3 is H; R.sup.5 is t-(CF.sub.3)(CH.sub.3).sub.2CO, t-(CF.sub.3).sub.2(CH.sub.3)CO, t-(CF.sub.3).sub.3CO, 2-phenyl-1,1,1,3,3,3-hexafluoro-prop-2-yloxy, pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl.

9. The method of claim 1, wherein R.sup.1 is an electron withdrawing group and R.sup.5 is an electron donating group.

10. The method of claim 1, wherein R.sup.1 is phenyl substituted with up to five substituents independently selected from CF.sub.3, F, Cl, or Br; R.sup.2 is C(CH.sub.3).sub.2C.sub.6H.sub.5 or C(CH.sub.3).sub.3; R.sup.3 is H; R.sup.5 is t-(CH.sub.3).sub.3CO, tri(C.sub.1-C.sub.4)silyloxy, or tri(phenyl)silyloxy, phenoxy or phenylthio, wherein the phenyl moiety may be substituted with up to five substituents independently selected from C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, phenoxy, phenyl, or halogen.

11. The method of claim 1, wherein both R.sup.1 and R.sup.5 are electron withdrawing groups.

12. The method of claim 1, wherein R.sup.1 is phenyl substituted with up to five substituents independently selected from CF.sub.3, F, Cl, or Br; R.sup.2 is C(CH.sub.3).sub.2C.sub.6H.sub.5 or C(CH.sub.3).sub.3; R.sup.3 is H; R.sup.5 is (CF.sub.3)(CH.sub.3).sub.2CO, (CF.sub.3).sub.2(CH.sub.3)CO, (CF.sub.3).sub.3CO, (C.sub.6H.sub.5)(CF.sub.3).sub.2CO, pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl.

13. The method of claim 1, wherein M is W.

Description

EXAMPLES

(1) 1. General Procedures

(2) All experiments were carried out under dry and oxygen free argon atmosphere using either standard Schlenk or glove-box techniques for organometallic synthesis. For the syntheses, reactions were carried out using high vacuum lines (10.sup.5 mBar) and glove-box techniques. Pentane, toluene and diethyl ether were purified using double MBraun SPS alumina column, and were degassed using three freeze-pump-thaw cycles before being used. DME and THF were distilled from Na/Benzophenone. Silica (Aerosil Degussa, 200 m.sup.2g.sup.1) was compacted with distilled water, calcined at 500 C. under air for 4 h and treated under vacuum (10.sup.5 mBar) at 500 C. for 12 h and then at 700 C. for 4 h (support referred to as SiO.sub.2-(700) and contained 0.26 mmol of OH per g as measured by titration with MeMgCl. All infrared (IR) spectra were recorded using a Bruker spectrometer placed in the glovebox, equipped with OPUS software. A typical experiment consisted in the measurement of transmission in 32 scans in the region from 4000 to 400 cm.sup.1. The .sup.1H and .sup.13C-NMR spectra were obtained on Bruker DRX 200, DRX 250 or DRX 500 spectrometers. The solution spectra were recorded in C.sub.6D.sub.6 at room temperature. The .sup.1H and .sup.13C chemical shifts are referenced relative to the residual solvent peak. Compounds [W(NAr)(CHCMe.sub.3)(OtBu).sub.2],.sup.1 [W(NAr)(CHCMe.sub.3)(OtBu.sub.F3).sub.2],.sup.1 [W(NAr)(CHCMe.sub.3)(OtBu.sub.F6).sub.2],.sup.1 [W(NArc.sub.Cl)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2],.sup.2 [W(NAr.sub.Cl)(CHCMe.sub.3)(OtBu.sub.F6).sub.2],.sup.2 [Mo(NAr.sub.Cl)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2],.sup.3 [(SiO)W(NAr)(CHCMe.sub.3)(Me.sub.2Pyr)],.sup.4 [(SiO)Mo(NAr)(CHCMe.sub.3)(Me.sub.2Pyr)],.sup.5 and [(SiO)Mo(NAr)(CHCMe.sub.3)(OtBu.sub.F6)].sup.6 were synthesized according to literature procedures. Further precursors or starting materials may be prepared according to such procedures or according to methods specified in the following. .sup.1Schrock, R. R.; De Pue, R. T.; Feldman, J.; Yap, K. B.; Yang, D. C.; Davis, W. M.; Park, L.; Dimare, M.; Schofield, M.; Anhaus, J.; Walborsky, E.; Evitt, E.; Krger, C.; Betz, P. Organometallics 1990, 2262. .sup.2Arndt, S.; Schrock, R. R.; Mller, P. Organometallics 2007, 1279. .sup.3Schrock, R. R.; Jamieson, J. Y.; Dolman, S. J.; Miller, S. A.; Bonitatebus, P. J., Jr.; Hoveyda, A. H. Organometallics 2002, 21, 409. .sup.4Blanc, F.; Berthoud, R.; Coperet, C.; Lesage, A.; Emsley, L.; Singh, R.; Kreickmann, T.; Schrock, R. R. Proc. Nat. Acad. Sci. 2008, 12123. .sup.5Blanc, F.; Thivolle-Cazat, J.; Basset, J M.; Coperet, C. Chem. Eur. J. 2008, 9030. .sup.6Rendon, N.; Berthoud, R.; Blanc, F.; Gajan, D.; Maishal, T.; Basset, J M.; Copret, C.; Lesage, A.; Emsley, L.; Marinescu, S. C.; Singh, R.; Schrock, R. R. Chem. Eur. J. 2009, 5083.

(3) Abbreviations:

(4) THF=tetrahydrofuran

(5) DME=1,2-dimethoxyethane

(6) Et.sub.2O=diethyl ether

(7) TfOH=trifluoromethanesulfonic acid

(8) LiMe.sub.2Pyr=lithium 2,5-dimethylpyrrolide

(9) 2. Syntheses

(10) 2.1 Synthesis of Precursors:

Precursor Example 1: [W(NAr)(CHCMe3)(OtBuF9)2], Ar=2,6-iPr2C6H3

(11) A cold (40 C.) suspension of (CF.sub.3).sub.3COLi (148 mg, 0.61 mmol, 2 equiv.) in diethyl ether (2 mL) was added to a solution of 250 mg of [W(NAr)(CHCMe.sub.3)(OTf).sub.2(DME)] (0.305 mmol, 1.05 equiv.) in cold diethyl ether (6 mL, 40 C.) while stirring. The dark red solution was stirred for 2 h at room temperature, and the volatiles were removed under reduced pressure. The dark red solid was suspended in pentane (4 mL) and filtered on Celite to afford a clear orange solution. The filtrate was taken to dryness in vacuo, and the orange powder dissolved back in pentane (2 mL). This drying/dissolution cycle was repeated four consecutive times, in order to remove all the coordinated DME molecules. Finally, the orange powder was solubilized in a minimum amount of pentane, and stored at 40 C. to give orange crystals, that were washed with cold (40 C.) pentane, affording after drying in vacuo 218 mg of [W(NAr)(CHCMe.sub.3)(OtBu.sub.F9).sub.2] (0.21 mmol, 69%). .sup.1H NMR (200 MHz, C.sub.6H.sub.6) (ppm) 9.45 (s, 1H, CHCMe.sub.3), 7.04-6.94 (m, 3H, Ar), 3.46 (2H, sep-tet, CHMe.sub.2), 1.15 (d, 12H, CHMe.sub.2), 1.06 (s, 9H, CHCMe.sub.3). .sup.19F NMR (200 MHz, C.sub.6D.sub.6) (ppm) 73.1 (s, 18F, C(CF.sub.3)).

Precursor Example 2: [W(NArCl)(CHCMe2Ph)(OtBuF9)2(DME)], ArCl=2,6-ClC6H3

(12) A cold (40 C.) suspension of (CF.sub.3).sub.3COLi (162.4 mg, 0.67 mmol, 2 equiv.) in diethyl ether (4 mL) was added to a suspension of 250 mg of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(OTf).sub.2(DME)] (0.33 mmol, 1 equiv.) in cold diethyl ether (6 mL, 40 C.) while stirring. The dark brown reaction mixture was stirred for 1.5 h at room temperature, and the volatiles were removed under reduced pressure, affording a light brown solid. The solid was extracted in pentane (15 mL), filtered on Celite and rinsed with pentane (25 mL). The volume of the filtrate was reduced to ca. 2 mL in vacuo and was stored at 40 C., affording an orange powder. The powder was filtered and rinsed with cold (40 C.) pentane (21 mL) to afford after drying in vacuo 165.2 mg of an orange powder of the title compound (0.159 mmol, 48%). Single crystals suitable diffraction studies of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(OtBu.sub.F9).sub.2] were grown in 40 C. toluene. .sup.1H NMR (300 MHz, C.sub.6H.sub.6) (ppm) 9.61 (s, 1H, CHCMe.sub.3), 7.45 (m, 2H, Ph), 7.00 (m, 2H, Ph), 6.74 (m, 1H, Ph), 6.69 (d, 2H, Ar, J=8.1 Hz), 6.19 (t, 1H, Ar, J=8.2 Hz), 3.00 (s, 6H, DME), 2.87 (s, 4H, DME), 1.44 (s, 6H, CHCMe.sub.2Ph). .sup.19F NMR (300 MHz, C.sub.6D.sub.6) (ppm) 73.1 (s, 18F, C(CF.sub.3)).

Precursor Example 3: [W(NArCl)(CHCMe2Ph)(OtBu)2], ArCl=2,6-ClC6H3

(13) To a cold THF solution (41 C., 20 mL) of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2] (200 mg, 0.30 mmol, 1 equiv.) was added dropwise over 1h a solution of tBuOH (44.6 mg, 0.60 mmol, 2 equiv.) in cold THF (41 C., 10 mL). The resulting brown solution was further stirred overnight in the MeCN/CO.sub.2 bath, slowly reaching room temperature. The resulting dark brown solution was dried in vacuo (2 h, 10.sup.2 mBar). The brown residue was extracted in cold pentane (40 C., 3 mL), filtered on Celite and evaporated to dryness to afford 108 mg of an oily orange solid (0.173 mmol, 57%). .sup.1H NMR (300 MHz, C.sub.6H.sub.6) (ppm) 8.09 (s, 1H, CHCMe.sub.2Ph), 7.54 (m, 2H, Ph), 7.16 (m, 2H, Ph), 7.08 (m, 1H, Ph), 6.97 (m, 2H, Ar.sub.Cl), 6.31 (t, 1H, Ar.sub.Cl, J=8.2 Hz), 1.72 (s, 6H, CHCMe.sub.2Ph), 1.26 (s, 18H, OCMe.sub.3).

Precursor Example 4: [W(NArCF3)(CHCMe2Ph)(Me2Pyr)2], (ArCF3=2-CF3C6H4, Me2Pyr=2,5-dimethylpyrrolide)

(14) A cold suspension of 47.5 mg of LiMe.sub.2Pyr (0.47 mmol, 2 equiv.) in toluene (40 C., 3 mL) was added dropwise under stirring to a cold toluene solution (40 C., 8 mL) of [W(NAr.sub.CF3)(CHCMe.sub.2Ph)(OTf).sub.2(DME)] (203 mg, 0.23 mmol, 1 equiv.). The suspension was stirred overnight, affording an orange solution and an off-white precipitate. The solution was filtered on Celite, affording a clear orange solution, and taken to dryness to yield a dark orange oil. This oil was triturated with cold (40 C.) pentane (21.5 mL) to afford after drying in vacuo 108 mg of a light yellow powder (0.16 mmol, 69%). .sup.1H NMR (300 MHz, C.sub.6H.sub.6) (ppm) 10.96 (s, 1H, CHCMe.sub.2Ph), 7.33 (m, 2H, Ph), 7.20-6.87 (m, 6H, Ph-Ar.sub.CF3), 6.75 (m, 1H, Ph), 6.52 (t, 1H, Ar.sub.CF3, J=8.0 Hz), 6.02 (br s, 6H, Me.sub.2Pyr), 2.11 (br s, 12H, Me.sub.2Pyr), 1.58 (s, 6H, CHCMe.sub.2Ph). .sup.19F NMR (200 MHz, C.sub.6D.sub.6) (ppm) 60.4 (s, 3F, CF.sub.3).

(15) 2.2 Synthesis of Supported Catalysts

Example 1: [(SiO)W(NAr)(CHCMe3)(OtBu)] (Ar=2,6-iPr2C6H3) (Representative Procedure)

(16) A solution of 104 mg of [W(NAr)(CHCMe.sub.3)(OtBu).sub.2] (0.181 mmol, 1.05 equiv.) in benzene (2 mL) was added to a suspension of SiO.sub.2-(700) (673 mg, 0.17 mmol) in benzene (2 mL) at room temperature. The suspension was slowly stirred at room temperature for 12 h, resulting in a fading of the color of the solution and a coloration of the silica to yellow. The yellow solid was collected by filtration, and was washed by four suspension/filtration cycles in benzene (42 mL). The resulting yellow solid was dried thoroughly under high vacuum (10.sup.5 mBar) at room temperature for 3 h to afford 672 mg of the title compound. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (33.7 mg, 1.05 equiv.), indicating that 0.07 mmol of tBuOH were released upon grafting (0.4 tBuOH/W.sub.surf). Elemental Analysis: W, 3.32%, C, 4.78%, H, 0.68%, N, 0.48% corresponding to 22 C/W (21 expected), 37.4 H/W (36 expected), 1.9 N (1 expected).

Example 2: [(SiO)W(NAr)(CHCMe3)(OtBuF3)] (Ar=2,6-iPr2C6H3, tBuF3OH(CF3)Me2COH)

(17) From a solution of [W(NAr)(CHCMe.sub.3)(OtBu.sub.F3).sub.2(DME)] and a suspension of SiO.sub.2-(700) (500 mg, 0.13 mmol) in benzene (2 mL) 552 mg of a yellow solid were isolated. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (11 mg, 1 equiv.), indicating that 0.11 mmol of tBu.sub.F3OH were released upon grafting (0.85 tBu.sub.F3OH/W.sub.surf). Elemental Analysis: W, 3.71%, C, 5.18%, H, 0.72%, N, 0.38% F, 1.09% corresponding to 21.4 C/W (21 expected), 35.4 H/W (33 expected), 1.3 N (1 expected).

Example 3: [(SiO)W(NAr)(CHCMe3)(OtBuF6)] (Ar=2,6-iPr2C6H3, tBuF6OH(CF3)2MeCOH)

(18) From a solution of 100 mg of [W(NAr)(CHCMe.sub.3)(OtBu.sub.F6).sub.2] (0.13 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (500 mg, 0.12 mmol) in benzene (2 mL), 512 mg of a light orange solid were isolated. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (11.8 mg, 0.5 equiv.), indicating that 0.10 mmol of tBu.sub.F6OH were released upon grafting (0.8 tBu.sub.F6OH/W.sub.surf). Elemental Analysis: W, 3.88%, C, 5.39%, H, 0.65%, N, 0.37%, F, 2.05% corresponding to 21.3 C/W (21 expected), 30.6 H/W (30 expected), 1.3 N (1 expected).

Example 4: [(SiO)W(NAr)(CHCMe3)(OtBuF9)] (Ar=2,6-iPr2C6H3, tBuF9OH(CF3)3COH)

(19) From a solution of 185.9 mg of [W(NAr)(CHCMe.sub.3)(OtBu.sub.Fg).sub.2] (0.21 mmol, 1.05 equiv.) in benzene (4 mL) and a suspension of SiO.sub.2-(700) (790 mg, 0.12 mmol) in benzene (3 mL) 857 mg of an orange solid were isolated. Elemental Analysis: W, 3.47%, C, 4.84%, H, 0.51%, N, 0.38%, F, 3.14% corresponding to 21.3 C/W (21 expected), 26.8 H/W (27 expected), 1.4 N (1 expected).

Example 5: [(SiO)W(NArCl)(CHCMe2Ph)(Me2Pyr)] (ArCl=2,6-ClC6H3, Me2Pyr=2,5-dimethylpyrrolide)

(20) From a solution of 138 mg of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2] (0.21 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (800 mg, 0.20 mmol) in benzene (2 mL) 790 mg of a light brown solid were isolated. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (38.7 mg, 1 equiv.), indicating that 0.13 mmol of Me.sub.2PyrH were released upon grafting (0.7 Me.sub.2PyrH/W.sub.surf).

Example 6: [(SiO)W(NArCl)(CHCMe2Ph)(OtBuF6)], (ArCl=2,6-ClC6H3, tBuF6OH(CF3)2MeCOH))

(21) From a solution of 101 mg of [W(NAr.sub.Cl)(CHCMe.sub.3)(OtBu.sub.F6).sub.2] (0.13 mmol, 1.05 equiv.) in benzene (2 mL) and a suspension of SiO.sub.2-(700) (463 mg, 0.12 mmol) in benzene (2 mL), 450 mg of a light orange solid were isolated. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (22.3 mg, 1 equiv.), indicating that 0.08 mmol of tBu.sub.F6OH were released upon grafting (0.7 tBu.sub.F6OH/W.sub.surf).

Example 7: [(SiO)W(NArCl)(CHCMe2Ph)(OtBuF9)], (ArCl=2,6-ClC6H3, tBuF9OH(CF3)3COH))

(22) From a solution of 98.5 mg of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(OtBu.sub.F9).sub.2(DME)] (0.10 mmol, 1.05 equiv.) in benzene (2 mL) and a suspension of SiO.sub.2-(700) (365 mg, 0.09 mmol) in benzene (2 mL) 360 mg of a light orange solid were obtained. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (17.7 mg, 1 equiv.), indicating that 0.09 mmol of DME were released upon grafting (0.9 DME/W.sub.surf).

Example 8: [(SiO)W(NArCF3)(CHCMe2Ph)(Me2Pyr)] (ArCF3=2-CF3C6H4, Me2Pyr=2,5-dimethylpyrrolide)

(23) From a solution of 75 mg of [W(NAr.sub.CF3)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2] (0.11 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (403 mg, 0.10 mmol) in benzene (2 mL), 390 mg of a yellow solid were isolated. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (38.7 mg, 1 equiv.), indicating that 0.09 mmol of Me.sub.2PyrH were released upon grafting (0.95 Me.sub.2PyrH/W.sub.surf).

Example 9: [(SiO)W(NArCl)(CHCMe2Ph)(OtBu)] ArCl=2,6-ClC6H3

(24) A solution of 100 mg of [W(NAr.sub.Cl)(CHCMe.sub.2Ph)(OtBu).sub.2] (0.16 mmol, 1.05 equiv.) in cold toluene (2 mL, 40 C.) was added to a suspension of SiO.sub.2-(700) (576 mg, 0.15 mmol) in cold toluene (2 mL, 40 C.). The suspension was slowly stirred at room temperature for 30 min, resulting in a fading of the color of the solution and a coloration of the silica to orange. The orange solid was collected by filtration, and was washed by four suspension/filtration cycles in benzene (42 mL). The resulting orange solid was dried thoroughly under high vacuum (10.sup.5 mBar) at room temperature for 5 h to afford 110 mg of the title compound. All the filtrate solutions were collected and analysed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (27.9 mg, 1 equiv.), indicating that 0.12 mmol of tBuOH were released upon grafting (0.8 tBuOH/W.sub.surf).

Example 10: [(SiO)Mo(NArCl)(CHCMe2Ph)(Me2Pyr)] (ArCl=2,6-ClC6H3, Me2Pyr=2,5-dimethylpyrrolide)

(25) From a solution of 113 mg of [Mo(NAr.sub.Cl)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2] (0.20 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (710 mg, 0.19 mmol) in benzene (2 mL), 690 mg of a red solid were isolated. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (34.5 mg, 1 equiv.), indicating that 0.14 mmol of Me.sub.2PyrH were released upon grafting (0.75 Me.sub.2PyrH/W.sub.surf).

Example 11: [(SiO)Mo(NAr)(CHCMe3)(OC(CF3)2Ph)] (Ar=2,6-iPr2C6H3)

(26) From a solution of 125 mg of [W(NAr)(CHCMe.sub.3)(OC(CF.sub.3).sub.2Ph).sub.2] (0.14 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (510 mg, 0.13 mmol) in benzene (2 mL), 517 mg of a yellow green solid were isolated. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (26.0 mg, 1 equiv.), indicating that 0.12 mmol of HOC(CF.sub.3).sub.2Ph were released upon grafting (0.9 HOC(CF.sub.3).sub.2Ph/W.sub.surf).

Example 12: [(SiO)Mo(NAr)(CHCMe2Ph)(OtBuF6)] (Ar=2,6-iPr2C6H3)

(27) (N. Rendon et. al., Chem. Eur. J. 2009, 15, 5083-5089)

Example 13: [(SiO)W(NAr)(CHCMe2Ph)(OSiPh3)] (Ar=2,6-iPr2C6H3)

(28) From a solution of 241 mg of [W(NAr)(CHCMe.sub.2Ph)(OSiPh).sub.2] (0.21 mmol, 1.05 equiv.) in benzene (4 mL) and a suspension of SiO.sub.2-(700) (810 mg, 0.23 mmol) in benzene (2 mL), a light orange solid were isolated. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as internal standard (52.3 mg, 1.33 equiv.), indicating that 0.48 mmol of HOSiPh.sub.3 were released upon grafting.

Example 14: [(SiO)W(NAr)(CHCMe3)(Me2Pyr)] (Ar=2,6-iPr2C6H3)

(29) (F. Blanc et al., Proc. Nat. Acad. Sci. 2008, 12123)

Example 15: [(SiO)Mo(NAr)(CHCMe2Ph)(Me2PYr)] (Ar=2,6-iPr2C6H3)

(30) (F. Blanc et al., J. Amer. Chem. Soc. 2007, 129, 8434-8435)

Example 16: [(SiO)W(NArF5)(CHCMe2Ph)(Me2Pyr)] (ArF5C6F5)

(31) From a solution of 59 mg of [W(NC.sub.6F.sub.5)(CHCMe.sub.2Ph)(Me.sub.2Pyr).sub.2] (0.086 mmol, 1.05 equiv.) in benzene (3 mL) and a suspension of SiO.sub.2-(700) (314 mg, 0.082 mmol) in benzene (3 mL), 343 mg of a orange-yellow solid were isolated. All the filtrate solutions were collected and analyzed by .sup.1H NMR spectroscopy in C.sub.6D.sub.6 using ferrocene as an internal standard, indicating that 0.07 mmol of Me.sub.2PyrH were released upon grafting (0.9 Me.sub.2PyrH/W.sub.surf). Elemental Analysis: W, 4.13%, C, 5.95%, H, 0.48%, N, 0.77% F, 2.17% corresponding to 22.1 C/W (22 expected), 21.2 H/W (20 expected), 2.4 N (2 expected), 5.1 F (5 expected).

Example 17: [(SiO)W(NAr)(CHCMe2Ph)(OArF5)] (Ar=2,6-iPr2C6H3) (ArF5C6F5)

(32) 3. Catalytic Activity

(33) 3.1 Ethenolysis of 9-octadecene:

(34) 9-Octadecene (E/Z isomer mixture) was purified by fractional distillation under inert atmosphere at reduced pressure (1 mbar) then it was percolated through a column of activated aluminum oxide 90 (basic, Brockman I, dried at 300 C. under 0.1 mbar vacuum for 24 h; column: d=4 cm, I=15 cm for 1 L of 9-octadecene) and was kept under inert atmosphere.

(35) In a nitrogen gas filled glove-box the calculated amount (0.5-5 mL) of 9-octadecene was added to the silica supported catalyst (3-5 mg) measured into a 30 ml glass vial. The vial was placed into a stainless steel autoclave and the reaction mixture was stirred by a magnetic stir bar under 10 atm of ethylene overpressure at room temperature for the specified time (see results table). The excess of ethylene was let out from the autoclave, the reaction mixture was quenched by wet ethyl acetate and the reaction mixture was analyzed by GC-FID (Shimadzu GC-2010 Plus; Zebron ZB-35HT Inferno).

(36) The subsequent table summarizes the results obtained with selected catalysts:

(37) TABLE-US-00001 Conversion (%) Catalyst (0.01 mol % W or Mo) (14 h) Example 2: [(SiO)W(NAr)(CHCMe.sub.3)(OtBu.sub.F3)] 41.8 Example 5: [(SiO)W(NAr.sub.CI)(CHCMe.sub.2Ph)(Me.sub.2Pyr)] 25.7 Example 12: [(SiO)Mo(NAr)(CHCMe.sub.2Ph)(OtBu.sub.F6)] 37.3 Example 12: [(SiO)Mo(NAr)(CHCMe.sub.2Ph)(OtBu.sub.F6)] 54.7 (loading 0.1 mol %) Example 15: [(SiO)Mo(NAr)(CHCMe.sub.2Ph)(Me.sub.2Pyr)] 53.9 Example 8: [(SiO)W(NAr.sub.CF3)(CHCMe.sub.2Ph)(Me.sub.2Pyr)] 39.5 Example 10: [(SiO)Mo(NAr.sub.CI)(CHCMe.sub.2Ph)(Me.sub.2Pyr)] 70.1
3.2 Ethenolysis of a Triglyceride (Rape-Seed Oil)

(38) Commercially available edible grade rapeseed oil sample (1 mL) was treated by 6.5 mol % triethylaluminium. Then 0.1 mol-% of the grafted silica catalyst was added. The reaction mixture was stirred in a stainless steel autoclave under 10 bar of ethylene atmosphere at 50 C. for 16 hours. To the reaction mixture sodium methylate in methanol (0.5 M, 20 mL) was added and the mixture was stirred at room temperature for 3 hours. After the end of the transesterification an aliquot (2 mL) was let through a small (7 mL) column of silica gel and the column was washed by tetrahydrofurane (25 mL). The combined elute was analyzed by GCMS-FID using heptadecane as internal standard. The resulting yield relates to methyl decenoate which has been formed in the transesterification reaction.

(39) TABLE-US-00002 Con- Yield of version methyl de- Catalyst (%) cenoate (%) Example 8: 34 16 [(SiO)W(NAr.sub.CF3)(CHCMe.sub.2Ph)(Me.sub.2Pyr)] Example 16: 66 38 [(SiO)W(NAr.sub.F5)(CHCMe.sub.2Ph)(Me.sub.2Pyr)]