Ruthenium-based metathesis catalysts, precursors for their preparation and their use

Abstract

The invention is directed to ruthenium-based metathesis catalysts of the Grubbs-Hoveyda type. The new 2-aryloxy-substituted ruthenium catalysts described herein reveal rapid initiation behavior. Further, the corresponding styrene-based precursor compounds are disclosed. The catalysts are prepared in a cross-metathesis reaction starting from styrene-based precursors which can be prepared in a cost-effective manner. The new Grubbs-Hoveyda type catalysts are suitable to catalyze ring-closing metathesis (RCM), cross metathesis (CM) and ring-opening metathesis polymerization (ROMP). Low catalyst loadings are necessary to convert a wide range of substrates including more complex and critical substrates via metathesis reactions at low to moderate temperatures in high yields within short reaction times.

Claims

1. A method for preparing a ruthenium catalyst of formula (II) ##STR00023## comprising reacting a compound of formula (I) ##STR00024## wherein a, b, c and d are, independently from each other, selected from hydrogen, straight chain or branched alkyl groups including C.sub.1-C.sub.10-alkyl, C.sub.1-C.sub.10-alkoxy, C.sub.1-C.sub.10-alkylthio, C.sub.1-C.sub.10-silyloxy, C.sub.1-C.sub.10-alkylamino, optionally substituted C.sub.6-C.sub.14-aryl, optionally substituted C.sub.6-C.sub.14-aryloxy, optionally substituted C.sub.6-C.sub.14-heteroaryl or electron-withdrawing groups (EWG); R.sup.1 is hydrogen, straight chain or branched C.sub.1-C.sub.10-alkyl, C.sub.1-C.sub.10-alkoxy, C.sub.1-C.sub.10-alkylthio, C.sub.1-C.sub.10-silyloxy, C.sub.1-C.sub.10-alkylamino, C.sub.1-C.sub.10-dialkylamino, C.sub.6-C.sub.14-aryl, C.sub.6-C.sub.14-aryloxy, C.sub.6-C.sub.14-heterocyclic or electron-withdrawing groups (EWG); R.sup.2 is hydrogen, straight chain or branched C.sub.1-C.sub.10-alkyl groups with a Ru-starting compound having the formula (V): ##STR00025## in a cross metathesis reaction, wherein L is a phosphine ligand selected from the group of tri-iso-propyl-phosphine, tricyclohexylphosphine (PCy.sub.3), tricyclopentylphosphine, cyclohexylphobane, 2,2,4-trimethylpentylphobane or isobutyl-phobane or a NHC ligand selected from the group of 1,3-bis-(2,4,6-trimethylphenyl)-imidazolidine-2-ylidene (“SIMes”), 1,3-bis-(2,6-di-isopropylphenyl)-imidazolidine-2-ylidene (“SIPr”) or 1,3-bis-(2,6-di-isopropylphenyl)-imidazoline-2-ylidene (“IPr”) and L′ is substituted or unsubstituted pyridine ligand; X is an anionic ligand selected from the group of halogen anions (Cl.sup.−, Br.sup.−, I.sup.−).

2. The method for preparing the catalysts according to claim 1, wherein L is a NHC ligand selected from the group of 1,3-bis-(2,4,6-trimethylphenyl)-imidazolidine-2-ylidene (“SIMes”), 1,3-bis-(2,6-di-isopropylphenyl)-imidazolidine-2-ylidene (“SIPr”) or 1,3-bis-(2,6-di-isopropylphenyl)-imidazoline-2-ylidene (“IPr”), L′ is pyridine, X is Cl.sup.−.

3. The method for preparing the catalyst according to claim 1, wherein the electron-withdrawing groups are halogen atoms, trifluormethyl (—CF.sub.3), nitro (—NO.sub.2), sulfinyl (—SO—), sulfonyl (—SO.sub.2—), formyl (—CHO), C.sub.1-C.sub.10-carbonyl, C.sub.1-C.sub.10-carboxyl, C.sub.1-C.sub.10-alkylamido, C.sub.1-C.sub.10-aminocarbonyl, nitrile (—CN) or C.sub.1-C.sub.10-sulfonamide.

4. The method for preparing the catalysts according to claim 1, wherein L is a N-heterocyclic carbene (NHC) ligand.

5. The method for preparing the catalysts according to claim 1, wherein L is a N-heterocyclic carbene ligand having the formula (III) or (IV) ##STR00026## wherein R.sup.3 is selected from the group of 2,4,6-trimethylphenyl, 2,6-di-isopropyl-phenyl, 3,5-di-tert.-butylphenyl, 2-methylphenyl and combinations thereof.

6. The method for preparing the catalysts according to claim 1, wherein L is a NHC ligand selected from the group of 1,3-bis-(2,4,6-trimethylphenyl)-imidazolidine-2-ylidene (“SIMes”), 1,3-bis-(2,6-di-isopropylphenyl)-imidazolidine-2-ylidene (“SIPr”) or 1,3-bis-(2,6-di-isopropylphenyl)-imidazoline-2-ylidene (“IPr”); X is Cl.sup.−; a, b, c and d each are hydrogen; R.sup.1 is hydrogen, dimethylamino (NMe.sub.2), nitro (NO.sub.2) or chlorine (Cl).

7. The method for preparing the catalysts according to claim 1, wherein L is a phosphine ligand selected from the group of tri-isopropylphosphine, tricyclohexylphosphine (PCy.sub.3), tricyclopentylphosphine and phospha-bicycloalkane compounds selected from the group of 9-cyclohexyl-9-phospha-bicyclo-[3.3.1]-nonane (“cyclohexylphobane”), 9-(2,2,4-trimethylpentyl)-9-phospha-bicyclo-[3.3.1]-nonane (“2,2,4-trimethylpentyl phobane”) and 9-isobutyl-9-phospha-bicyclo-[3.3.1]-nonane (“isobutylphobane”).

8. The method for preparing the catalysts according to claim 1, the catalyst is a catalyst of formula (IIa) ##STR00027##

9. The method for preparing the catalysts according to claim 1, the catalyst is a catalyst of formula (IId) ##STR00028##

10. The method for preparing the catalysts according to claim 1, the catalyst is a catalyst of formula (IIe) ##STR00029##

11. The method for preparing the catalysts according to claim 1, the catalyst is a catalyst of formula (IIh) ##STR00030##

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the conversion (in %) of N,N-diallyltosylamide (0.1 mol/L) during RCM reaction over a reaction period of 210 minutes at 0° C. in toluene using 0.025 mol-% (250 ppm) of catalysts of formulas (a), (IIb) and (IIf).

(2) FIG. 2 shows the conversion (in %) of N,N-diallyltosylamide (0.1 mol/L) during RCM reaction over a reaction period of 20 minutes at 0° C. in toluene using 0.025 mol-% (250 ppm) of catalysts of formulas (IIb) and (IIf).

(3) FIG. 3 shows an ORTEP plot of the crystal structure of catalyst (IIb). Important bond lengths (pm) and angles (°) are (two independent molecules of catalyst (IIb) are observed in solid state, which differ with respect to the orientation of the phenyl group relative to the rest of the molecule, the first number corresponds to molecule 1 followed by the respective data for molecule 2): Ru—O 226.6(4), 230.5(3); Ru—C(NHC) 198.4(5), 197.0(6); Ru═CHR 182.1(5), 180.9(5), Ru—Cl 230.7(2), 232.3(2), 232.1(2), 234.0(2); Cl—Ru—Cl 153.71(6), 158.31(6). The significant variability of the Ru—O distances in the two observed molecules of catalyst (IIb) indicates that there is a shallow energy potential curve for the Ru—O bond and, thus, an increased sensibility of the bond with regard to minor disturbances.

(4) FIG. 4 shows the absorbance-time curve of catalyst (IId) (1×10.sup.−4 mol/L) during reaction with butyl vinyl ether (0.01 M) in toluene at 30° C. The data are fitted using (y=A1.Math.exp(−x/t.sub.1)+y0) and (k.sub.obs=1/t.sub.1). The absorbance of catalyst (IId) probably resulting from the ligand-metal-charge transfer (LMCT band) is measured at 370 nm. A fast decrease of the absorbance of catalyst (IId) was observed. The dissociation reaction required less than 20 seconds, even at a very low concentration of butyl vinyl ether (0.01 mol/L) and at a temperature, which was slightly above ambient temperature (30° C.). From this it is evident that the Ru—O bond is broken rapidly in the presence of the olefin.

(5) The invention is further described by the following examples without limiting or narrowing the scope of protection.

EXAMPLES

General Remarks

(6) All chemicals are purchased as reagent grade from commercial suppliers and used without further purification, unless otherwise noted. All reactions involving ruthenium complexes are performed under an atmosphere of argon. CH.sub.2Cl.sub.2 (99.5%) and pentane (99%) are obtained from Gruessing GmbH, toluene from Sigma-Aldrich (Lab. Reagent grade, 99.3%). These solvents are dried and degassed by using a column purification system. In this system, the solvents are sparged and pressurized with argon (0.1 to 1 bar), followed by successive passing through a column filled with activated alumina and a second column, either filled with a supported copper catalyst (pentane) or again activated alumina (CH.sub.2Cl.sub.2). Dimethylformamide is refluxed over calcium hydride and distilled under argon atmosphere. Tetrahydrofuran is dried over sodium and distilled under argon atmosphere. All solvents are stored over molecular sieves (4 Å).

(7) .sup.1H and .sup.13C nuclear magnetic resonance spectra are recorded with a Bruker DRX300 spectrometer. The chemical shifts are given in parts per million (ppm) on the delta scale (δ) and are referenced to tetramethylsilane (.sup.1H—, .sup.13C-NMR=0.0 ppm) or the residual peak of CHCl.sub.3 (.sup.1H-NMR=7.26 ppm, .sup.13C-NMR=77.16 ppm). Abbreviations for NMR data: s=singlet; d=doublet; t=triplet; q=quartet; sep=septet; m=multiplet; bs=broad signal. Preparative chromatography is performed using Merck silica 60 (0.063-0.02 mesh). GC experiments are run on a Clarus 500 GC with autosampler and FID detector. Column: Varian CP-Sil 8 CB (l=15 m, d.sub.i=0.25 mm, d.sub.F=1.0 lm), N.sub.2 (flow: 17 cm s.sup.−1; split 1:50); Injector-temperature: 270° C., detector temperature: 350° C.

Example 1

Preparation of the Styrene-Based Precursors (Ia) to (Id)

(8) The preparation is carried out starting from 4-substituted phenols (for preparing styrene-based precursors of formula (Ia) to (Ic)) or starting from 4-substituted 1-fluoro-benzene for preparing styrene-based precursor of formula (Id). In the first reaction step, the respective benzaldehyde intermediates are prepared. The benzaldehyde intermediates are then converted to the respective precursor (Ia) to (Id) in a second reaction step.

a) Preparation of 2-(4-(dimethylamino)phenoxy)benzaldehyde, 2-phenoxy-benzaldehyde and 2-(4-chlorophenoxy)benzaldehyde

(9) The benzaldehyde intermediates are synthesized following literature procedures with modifications. Into a dry Schlenk flask under argon atmosphere the corresponding phenol (17.7 mmol), 2-fluorobenzaldehyde (2.0 g, 16.1 mmol), potassium carbonate (5.6 g, 40.3 mmol) and anhydrous DMF (40 mL) are added at room temperature. The mixture is warmed in a sealed flask to 170° C. and stirred at this temperature for 2 h (for preparing 2-phenoxy-benzaldehyde and 2-(4-chlorophenoxy)benzaldehyde) or at 150° C. for 1.5 h (for preparing 2-(4-(dimethylamino)phenoxy)benzaldehyde). Then the mixture is allowed to cool to room temperature and is treated with water (200 mL) and the product is extracted with diethyl ether (3×50 mL). The combined organic layers are washed with NaOH (1 M, 50 mL), brine (150 mL), dried over anhydrous MgSO.sub.4 and evaporated in vacuum. The residue is purified by column chromatography (cyclohexane/ethyl acetate 10:1, v/v (for preparing 2-phenoxy-benzaldehyde and 2-(4-chlorophenoxy)benzaldehyde) or used in next reaction without purification (in case of 2-(4-(dimethylamino)phenoxy)-benzaldehyde).

(10) 2-(4-(dimethylamino)phenoxy)benzaldehyde is obtained as a white solid (3.07 g, 79% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 10.59 (d, J=0.8 Hz, 1H), 7.90 (dd, J=7.8, 1.8 Hz, 1H), 7.44 (ddd, J=8.5, 7.3, 1.8 Hz, 1H), 7.12-7.05 (m, 1H), 7.03-6.97 (m, 2H), 6.84-6.74 (m, 3H), 2.96 (s, 6H).

(11) .sup.13C NMR (75 MHz, CDCl.sub.3) δ 189.85, 161.75, 148.14, 145.47, 135.76, 128.33, 126.05, 122.23, 121.25, 116.90, 114.18, 41.34.

(12) 2-phenoxybenzaldehyde is obtained as a yellow oil (2.52 g, 79% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 10.52 (d, J=0.8 Hz, 1H), 7.94 (dd, J=7.8, 1.8 Hz, 1H), 7.51 (ddd, J=8.4, 7.3, 1.8 Hz, 1H), 7.43-7.35 (m, 2H), 7.22-7.15 (m, 2H), 7.10-7.04 (m, 2H), 6.90 (dd, J=8.4, 0.8 Hz, 1H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 189.45, 160.10, 156.53, 135.85, 130.22, 128.55, 127.03, 124.44, 123.44, 119.51, 118.60.

(13) 2-(4-chlorophenoxy)benzaldehyde is obtained as a yellow solid (3.07 g, 82% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 10.48 (d, J=0.7 Hz, 1H), 7.94 (dd, J=7.8, 1.8 Hz, 1H), 7.53 (ddd, J=8.4, 7.3, 1.8 Hz, 1H), 7.37-7.33 (m, 2H), 7.24-7.19 (m, 1H), 7.03-6.99 (m, 2H), 6.89 (dd, J=8.4, 0.7 Hz, 1H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 189.14, 159.62, 155.20, 135.95, 130.26, 129.65, 128.85, 127.13, 123.91, 120.72, 118.60.

b) Synthesis of 2-(4-nitrophenoxy)benzaldehyde

(14) Into a dry Schlenk flask under argon atmosphere are added 1-fluoro-4-nitrobenzene (2.0 g, 14.2 mmol), salicylic aldehyde (2.1 g, 17.0 mmol), potassium carbonate (4.9 g, 35.5 mmol) and anhydrous DMF (40 mL). The mixture is warmed in a sealed flask to 100° C. and stirred at this temperature overnight. Then the mixture is allowed to cool to room temperature, treated with water (200 mL) and the product is extracted with diethyl ether (3×50 mL). Combined organic layers are washed with NaOH (1M in water, 50 mL) and brine (150 mL), dried over anhydrous MgSO.sub.4 and evaporated in vacuo. Residue is purified by column chromatography (cyclohexane/ethyl acetate 4:1, v/v).

(15) 2-(4-nitrophenoxy)benzaldehyde is obtained as a yellow solid (2.40 g, 69% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 10.34 (d, J=0.7 Hz, 1H), 8.28-8.23 (m, 2H), 8.00 (dd, J=7.8, 1.8 Hz, 1H), 7.66 (dd, J=8.3, 7.4, 1.8 Hz, 1H), 7.41-7.35 (m, 1H), 7.13-7.06 (m, 3H).

(16) .sup.13C NMR (75 MHz, CDCl.sub.3) δ 188.36, 162.64, 157.14, 143.61, 136.26, 129.71, 128.14, 126.31, 125.85, 120.93, 117.87. HRMS: m/z calcd for C.sub.13H.sub.9NO.sub.4 243.0542; found: 243.0531. Analysis calcd. for C.sub.13H.sub.9NO.sub.4 (243.05): C, 64.18, H, 3.73, N, 5.76; found: C, 64.23, H, 3.72, N, 5.88.

c) Vinylation of the Benzaldehyde Intermediates

(17) A Schlenk flask containing methyltriphenylphosphonium iodide (3.0 g, 7.42 mmol) is evacuated and back-filled with argon three times. Anhydrous tetrahydrofuran (50 mL) is added by syringe and the formed suspension is cooled to −10° C. KOtBu (902 mg, 8.04 mmol) is added in portions to the stirred mixture under a stream of argon, and stirring continued at −10° C. for 20 minutes. Subsequently, one of the benzaldehyde intermediates (6.18 mmol) is added. The mixture is allowed to warm to room temperature, stirred overnight and poured into water (500 mL). The product is extracted with diethyl ether (3×100 mL). The organic phases are combined, washed with brine and dried over magnesium sulfate. The solvent is removed in vacuo and the residue is purified by column chromatography (cyclohexane/ethyl acetate 20:1, v/v).

(18) Precursor (Ia) is obtained as a colorless solid (1.18 g, 80% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 7.58 (dd, J=7.7, 1.8 Hz, 1H), 7.20-7.01 (m, 3H), 6.96-6.89 (m, 2H), 6.80 (dd, J=8.2, 1.2 Hz, 1H), 6.76 (d, J=9.0 Hz, 2H), 5.82 (dd, J=17.7, 1.4 Hz, 1H), 5.30 (dd, J=11.1, 1.4 Hz, 1H), 2.93 (s, 6H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 155.69, 147.37, 131.49, 128.89, 128.66, 126.61, 122.78, 120.11, 117.92, 115.02, 114.34, 41.51. HRMS: m/z calcd for C.sub.16H.sub.17NO 239.1304; found: 239.1310. Analysis calcd. for C.sub.16H.sub.17NO (239.13): C, 80.30, H, 7.16, N, 5.85; found C, 79.88, H, 7.11, N, 5.83.

(19) Precursor (Ib) is obtained as a colorless solid (0.99 g, 82% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 7.62 (dd, J=7.8, 1.7 Hz, 1H), 7.34-7.30 (m, 2H), 7.24 (dd, 1H), 7.16-7.13 (m, 1H), 7.07 (tt, J=7.6, 1.1 Hz, 1H), 7.01 (dd, J=17.7, 11.1 Hz, 1H), 6.97-6.94 (m, 2H), 6.92 (dd, J=8.1, 1.1 Hz, 1H), 5.81 (dd, J=17.7, 1.3 Hz, 1H), 5.29 (dd, J=11.1, 1.3 Hz, 1H).

(20) .sup.13C NMR (75 MHz, CDCl.sub.3) δ 158.05, 153.75, 131.12, 129.97, 129.83, 129.14, 126.77, 124.21, 122.81, 120.23, 117.91, 115.51. Elemental analysis calcd. for C.sub.14H.sub.12O (196.09) C, 85.68, H, 6.16; found C, 85.49, H, 6.11.

(21) Precursor (Ic) is obtained as a colorless liquid (1.20 g, 84% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 7.60 (dd, J=7.7, 1.8 Hz, 1H), 7.28-7.20 (m, 3H), 7.18-7.12 (m, 1H), 6.99-6.87 (m, 2H), 6.87-6.82 (m, 2H), 5.78 (dd, J=17.7, 1.3 Hz, 1H), 5.27 (dd, J=11.1, 1.2 Hz, 1H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 156.76, 153.32, 130.85, 130.07, 129.79, 129.26, 127.77, 126.93, 124.66, 120.33, 118.97, 115.86. HRMS: m/z calcd for C.sub.14H.sub.11ClO 230.0494; found 230.04815. Elemental analysis calcd. for C.sub.14H.sub.11ClO (230.69): C, 72.89, H, 4.81; found C, 72.82, H, 4.92.

(22) Precursor (Id) is obtained as a yellow solid (1.15 g, 77% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) δ 8.22-8.16 (m, 2H), 7.68-7.64 (m, 2H), 7.38-7.24 (m, 1H), 7.04-7.00 (m, 1H), 6.97-6.91 (m, 2H), 6.79 (dd, J=17.7, 11.1 Hz, 1H), 5.79 (dd, J=17.7, 1.1 Hz, 1H), 5.29 (dd, J=11.1, 1.1 Hz, 1H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 163.61, 151.47, 142.67, 130.74, 130.20, 129.65, 127.31, 126.21, 126.14, 121.73, 116.81, 116.51. HRMS: m/z calcd for C.sub.14H.sub.11NO.sub.3 241.0739; found: 241.0714 Elemental analysis calcd. for C.sub.14H.sub.11NO.sub.3 (241.25) C, 69.70, H, 4.60, N, 5.81; found C, 69.93, H, 4.68, N, 5.69.

Example 2

a) Preparation of Catalysts (IIa) to (IIc) and (IIe) to (IIh)

(23) A flame-dried Schlenk tube containing [RuCl.sub.2(SIMes)(3-phenylindeneylidene)(py)] (200 mg, 0.27 mmol; Umicore AG & Co. KG, Hanau, Germany) (for preparing catalysts (IIa) to (IIc)) or [RuCl.sub.2(SIPr)(3-phenylindeneylidene)(py)] (200 mg, 0.24 mmol; Umicore AG & Co. KG, Hanau, Germany) (for preparing catalysts (IIe) to (IIh)) is evacuated and back-filled with argon three times. Methylene chloride (4 mL), the respective styrene-based precursor (0.30 mmol for preparing catalysts (IIa) to (IIc) or 0.26 mmol for preparing catalysts (IIe) to (IIh)) and Amberlyst resin (275 mg for preparing catalysts (IIa) to (IIc) or 250 mg for preparing catalysts (IIe) to (IIh), dry form, 4.70 mmol H.sup.+/g) are added under an atmosphere of argon. The mixture is stirred at 40° C. for 30 minutes for preparing catalysts (IIa) to (IIc) or 60 minutes for preparing catalysts (IIf) to (IIh) or at room temperature for 1 h for preparing catalyst (IIe) and then filtered, to separate the resin. The filtrate is evaporated in vacuo and the remaining solid is treated with pentane (10 mL) and the resulting suspension is kept in an ultrasonic bath for 1 min. Solid residue is filtered, washed with methanol (5 mL) and pentane (10 mL) and dried in vacuo.

(24) Catalyst (IIa) is obtained as a green solid (135 mg, 71% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.71 (s, 1H), 7.37 (t, J=7.5 Hz, 1H), 7.13 (d, J=8.3 Hz, 2H), 7.03 (s, 4H), 7.00-6.88 (m, 3H), 6.61 (d, J=8.0 Hz, 3H), 4.15 (s, 4H), 2.93 (s, 6H), 2.47 (s, 12H), 2.37 (s, 6H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 292.65, 210.50, 154.24, 143.89, 138.79, 136.22, 129.54, 129.46, 128.74, 127.69, 123.66, 122.90, 122.53, 113.86, 113.13, 51.81, 41.20, 21.24, 19.43. HRMS: m/z calcd for C.sub.36H.sub.41N.sub.3O.sub.4Cl.sub.2Ru 703.16809; found: 703.1661.

(25) Catalyst (IIb) is obtained as a green solid (142 mg, 80% yield). .sup.1H NMR (300 MHz, CDCl.sub.3): δ 16.71 (d, J=0.9 Hz, 1H), 7.44-7.36 (m, 1H), 7.25-7.14 (m, 5H), 7.03 (s, 4H), 7.00 (d, J=1.8 Hz, 1H), 6.94 (td, J=7.5, 0.8 Hz, 1H), 6.66 (d, J=8.3 Hz, 1H), 4.16 (s, 4H), 2.46 (s, 12H), 2.37 (s, 6H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 292.53, 210.04, 153.24, 153.04, 144.21, 138.85, 136.03, 129.52, 129.44, 126.03, 124.21, 122.82, 122.08, 51.79, 21.22, 19.44. HRMS: m/z calcd for C.sub.34H.sub.36N.sub.2OCl.sub.2Ru 660.1253; found: 660.1239.

(26) Catalyst (IIc) is obtained as a green solid (129 mg, 69% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.70 (s, 1H), 7.42 (t, J=7.1 Hz, 1H), 7.24-7.18 (m, 4H), 7.06-6.94 (m, 6H), 6.65 (d, J=8.1 Hz, 1H), 4.16 (s, 4H), 2.45 (s, 12H), 2.38 (s, 6H). .sup.13C NMR (75 MHz, CDCl.sub.3) δ 292.09, 209.55, 152.61, 151.71, 144.10, 138.98, 138.83, 135.94, 131.40, 129.55, 124.60, 123.43, 122.96, 114.00, 51.80, 21.23, 19.41. HRMS: m/z calcd for C.sub.34H.sub.35N.sub.2OCl.sub.3Ru 694.0820; found: 694.0845.

(27) Catalyst (IIe) is obtained as a green solid (139 mg, 73% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.59 (s, 1H), 7.49 (t, J=7.6 Hz, 2H), 7.32 (d, J=7.6 Hz, 5H), 7.22 (d, J=8.1 Hz, 2H), 6.95-6.83 (m, 2H), 6.64-6.52 (m, 3H), 4.13 (s, 4H), 3.64 (sep, J=6.2 Hz, 4H), 2.92 (s, 6H), 1.27 (d, J=6.7 Hz, 12H), 1.19 (d, J=6.4 Hz, 12H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 287.86, 213.42, 148.85, 142.88, 137.25, 129.67, 129.33, 124.67, 123.74, 123.46, 121.94, 113.73, 113.04, 54.77, 41.10, 28.70, 26.49, 24.07. HRMS: m/z calcd for C.sub.42H.sub.53N.sub.3OCl.sub.2Ru 787.2567; found: 787.2600. Elemental analysis calcd. for C.sub.42H.sub.53N.sub.3OCl.sub.2Ru (787.88): C, 64.03, H, 6.78, N, 5.33; found C, 64.56, H, 6.96, N, 5.12.

(28) Catalyst (IIf) is obtained as a green solid (151 mg, 84% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.59 (d, J=0.5 Hz, 1H), 7.49 (t, J=7.7 Hz, 2H), 7.39-7.24 (m, 9H), 7.23-7.18 (m, 1H), 6.95 (dd, J=7.6, 1.6 Hz, 1H), 6.89 (t, J=7.4 Hz, 1H), 6.56 (d, J=8.3 Hz, 1H), 4.14 (s, 4H), 3.63 (sep, J=6.7 Hz, 4H), 1.27 (d, J=6.9 Hz, 12H), 1.17 (d, J=6.6 Hz, 12H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 287.38, 212.79, 154.03, 153.04, 148.87, 143.08, 137.11, 129.74, 129.50, 129.33, 126.46, 124.66, 123.93, 123.16, 122.19, 113.85, 54.76, 28.71, 26.51, 23.97. HRMS: m/z calcd for C.sub.40H.sub.48N.sub.2OCl.sub.2Ru 744.2185; found: 744.2178.

(29) Catalyst (IIg) is obtained as a green solid (141 mg, 75% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.57 (s, 1H), 7.50 (t, J=7.7 Hz, 2H), 7.39-7.35 (m, 1H), 7.34-7.29 (m, 6H), 7.26-7.23 (m, 2H), 7.00-6.88 (m, 2H), 6.55 (d, J=8.3 Hz, 1H), 4.15 (s, 4H), 3.61 (sep, J=6.8 Hz, 4H), 1.27 (d, J=6.9 Hz, 12H), 1.18 (d, J=6.6 Hz, 12H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 286.85, 212.24, 153.61, 151.49, 148.85, 142.93, 137.00, 131.91, 129.82, 129.62, 129.37, 124.69, 124.51, 124.32, 122.34, 113.69, 54.76, 28.73, 26.49, 23.97. HRMS: m/z calcd for C.sub.40H.sub.47N.sub.2OCl.sub.3Ru 778.17584; found: 778.1784. Elemental analysis calcd. for C.sub.40H.sub.47N.sub.2OCl.sub.3Ru (778.80) C, 61.63, H, 6.08, N, 3.60; found 61.19, H, 6.16, N, 3.68.

(30) Catalyst (IIh) is obtained as a green solid (125 mg, 66% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.55 (s, 1H), 8.18-8.14 (m, 2H), 7.53-7.47 (m, 4H), 7.45-7.40 (m, 1H), 7.33 (d, J=7.7 Hz, 4H), 7.00-6.98 (m, 2H), 6.63 (d, J=8.3 Hz, 1H), 4.16 (s, 4H), 3.57 (sep, J=6.7 Hz, 4H), 1.27 (d, J=6.9 Hz, 12H), 1.17 (d, J=6.6 Hz, 12H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 285.70, 211.08, 157.97, 152.17, 148.89, 145.60, 143.22, 136.77, 129.97, 129.39, 126.16, 125.35, 124.71, 123.29, 122.80, 116.78, 114.27, 54.77, 28.79, 26.51, 23.89. HRMS: m/z calcd for C.sub.40H.sub.74N.sub.3O.sub.3Cl.sub.2Ru 789.2032; found: 789.2029.

a) Preparation of Catalyst (IId)

(31) A flame-dried Schlenk tube containing [RuCl.sub.2(SIMes)(3-phenylindeneylidene) (py)] (200 mg, 0.27 mmol; Umicore AG & Co. KG, Hanau, Germany) is evacuated and back-filled with argon three times. Tetrahydrofuran (5 mL) is added and the resulting suspension is cooled to 0° C. Then styrene-based precursor (Id) (65.7 mg, 0.27 mmol) and Amberlyst resin (275 mg, dry form, 4.70 mmol H.sup.+/g) is added and the mixture is stirred at −5° C. for 30 minutes, filtered and evaporated in vacuo. The solid residue is washed with methanol (5 mL), pentane (10 mL) and dried in vacuo.

(32) Catalyst (IId) is obtained as a green solid (141 mg, 75% yield). .sup.1H NMR (500 MHz, CDCl.sub.3) δ 16.69 (s, 1H), 8.12 (d, J=7.2 Hz, 2H), 7.49 (s, 1H), 7.35 (d, J=7.4 Hz, 2H), 7.04 (s, 6H), 6.79 (d, J=7.3 Hz, 1H), 4.18 (s, 4H), 2.43 (s, 12H), 2.40 (s, 6H). .sup.13C NMR (126 MHz, CDCl.sub.3) δ 291.42, 208.52, 158.38, 150.86, 145.17, 144.58, 139.16, 138.94, 129.59, 129.46, 125.78, 125.30, 123.47, 121.80, 114.94, 51.79, 21.28, 19.43.

Example 3

Catalyst Testing

(33) The new Ru-based catalysts are exemplarily evaluated in ring-closing metathesis reactions (RCM). Furthermore, the activity is compared with a conventional catalyst known from the prior art, i.e. catalysts of formulas (a), (c) and (d).

Results of RCM

(34) Catalysts of formulas (IIa) to (IIh) are systematically tested for a number of ring closing metathesis reactions leading to N-heterocycles. A comparison with prior art catalyst (a) is made.

(35) The ring-closing reactions are carried out in toluene at 50° C. with a reaction time of 15 min. The substrate is present in an amount of 0.5 mol/L. Reactions are carried out in sealed 10 mL Schlenk tubes under an atmosphere of argon. In a 10 mL Schlenk tube, substrate is dissolved in dry toluene under an atmosphere of argon. This solution is heated to 50° C. and catalyst (0.0025 to 0.02 mol-%) (25 to 200 ppm) from a stock solution (0.75 mmol/L) in toluene is added. The latter is prepared by adding 4.0.Math.10.sup.−6 mol of catalyst (IIa) to (IIh) into a 10 mL Schlenk tube, evacuating the tube, filing the tube with argon and subsequent addition of 5.34 mL of dried toluene under a stream of argon. The Schlenk tube is kept in an ultrasonic bath for 1 min for complete dissolution of the inventive catalyst.

(36) The substrate concentration is defined as c(S)=n(S)/(V(S)+V(toluene)+V (stock solution)). For the determination of substrate conversion, samples (10 μL, substrate conc. 0.5 M) are taken after the specified times under a stream of argon and injected into GC vials containing 250 μL of a 25% (v/v) ethyl vinyl ether solution in toluene. The conversions are determined by GC. The degree of conversions is the average conversion of two runs. The results are presented in Table 1.

(37) The catalysts according to the present invention allow for excellent substrate conversions of ≥60% within less than 15 minutes of reaction time at a low catalyst loading of between and at low to moderate temperatures. For the majority of RCM substrates a conversion of even about 90% or higher within 15 minutes of reaction time is measured.

(38) In this context, the new Ru-based catalysts of the present invention seem to be especially efficient in RCM reactions leading to di- or tri-substituted cyclic olefins (ref to Table 1, entry 6 and Table 2).

(39) TABLE-US-00001 TABLE 1 Conversion (in %) in RCM reactions of various substrates for catalysts of the invention (IIa to IIh) and prior art catalyst (a) at different catalyst loadings Catalyst loading Conversion (%) Entry Substrate [ppm] (a) IIa IIb IIc IId IIe IIf IIg IIh 1 25 70 83 90 73 83 99 — 81 99 2 15 — — 74 64 — 91 96 78 92 3 50 60 71 60 — 54 89 91 — 83 4 50 — — 91 — 80 — 98 — — 5 0 200 — 92 92 — 77 99 99 — 98 6 50 39 — 61 — — 90 72 — 84 Reaction conditions: Toluene solvent, 0.5 M substrate, T = 50° C., reaction time 15 minutes, conversions detected by GC, average of two runs.

(40) Apart from the low catalyst loading, the short reaction time required for such reactions is most notable—all of the reactions studied are almost completed within less than 15 min.

(41) TON and TOF are calculated for substrate of entry no. 4 and catalyst (IIf). Accordingly, by using catalyst (IIf) a TON of 6.4×10.sup.4 and a TOF of 2.56×10.sup.5 h.sup.−1 is observed. This is a significant improvement with respect to the prior art.

(42) Catalyst of formula (IIb) is tested under the above mentioned conditions for a ring closing metathesis reaction with a more complicated and critical substituted olefinic substrate in comparison with N-chelated Grubbs-Hoveyda-type catalysts of formulas (c) and (d) known from the prior art.

(43) TABLE-US-00002 TABLE 2 Conversion (in %) in RCM reactions for catalyst (IIb) of the invention and prior art catalysts (c) and (d) Catalyst loading Conversion (%) Substrate [ppm] (c) (d) IIb 50 58 54 78 Reaction conditions: Toluene solvent, 0.5 M substrate, T = 50° C., reaction time 15 minutes, conversions detected by GC, average of two runs.

Comparative Tests with Prior Art Catalysts

(44) In the RCM of N,N-diallyltosylamide at 0° C. catalysts of formula (IIb) and (IIf) are significantly faster than the prior art catalyst (a). At low temperatures fast initiation translates into excellent catalytic activities compared to catalyst (a) known from the art, which initiate considerably more slowly. FIG. 1 shows the results of the RCM reaction. After 120 min a complete conversion is almost obtained for catalysts (IIb) and (IIf), while it takes much longer for the less rapidly initiating catalyst (a). The faster activation of catalysts (IIb) and (IIf) is evident from the faster initial transformation of the substrate to the respective RCM product.

(45) The fast initiation and substrate conversion is also evident from FIG. 2, which gives a detailed view on the conversion (in %) of N,N-diallyltosylamide within the first 20 minutes for catalysts (IIb) and (IIf). Accordingly, a conversion of more than 20% is obtained even within 9 minutes at 0° C. Figure also shows that catalyst (IIb) initiates faster than catalyst (IIf).

(46) The increased catalytic activity of the catalysts according to the present invention compared with prior art catalyst (a) is also confirmed in Table 1. According to Table 1, the catalysts of the present invention show a considerably higher activity in RCM reactions with different substrates.

(47) Furthermore, a strong influence of temperature on the catalyst performance is noted. In order to obtain about 85% yield in the RCM of N,N-diallyltosylamide at 0° C., about 250 ppm of the catalyst of formula (IIf) are required at a reaction time of about 180 min. At 50° C. a yield of 96% is obtained within 15 min using only 15 ppm of the catalyst of formula (IIf) (ref to Table 1).

(48) Still further, from Table 2 it is evident that catalyst (IIb) enables superior conversion rates of important and more critical substrates such as diethylallyl-(2-methylallyl)malonate compared with the N-chelated catalysts known from the prior art. Considering the more complicated synthesis of N-chelated catalysts as well as the stability of N-chelated Grubbs-Hoveyda-type catalysts, which is usually limited, the Ru-based catalysts according to the present invention provide exceptional advantages in view of the catalysts already known.