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Latent, high-activity olefin metathesis catalysts containing an N-heterocyclic carbene ligand

a technology of olefin metathesis and ligand, which is applied in the field of olefin metathesis catalysts, can solve the problems of limited lifetime, modest degree of latency control, and lower activity of bisphosphine complexes

Inactive Publication Date: 2005-11-24
CALIFORNIA INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While such complexes are capable of catalyzing a considerable number of olefin metathesis transformations, these bisphosphine complexes can exhibit lower activity than desired and, under certain conditions, can have limited lifetimes.
However, only a modest degree of control of the latency can be achieved by varying the identity of the substituent groups of the vinylidene ligand and such vinylidene complexes are often not efficient metathesis catalysts for unstrained olefins.
Although these catalysts do initiate more slowly than their bis-phosphine counterparts, they lack the high activity of the NHC catalyst systems.
These observations suggest that it is difficult to achieve latency with the high-activity catalysts comprising NHC ligands.

Method used

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  • Latent, high-activity olefin metathesis catalysts containing an N-heterocyclic carbene ligand
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  • Latent, high-activity olefin metathesis catalysts containing an N-heterocyclic carbene ligand

Examples

Experimental program
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Effect test

example 1

Synthesis of Catalyst 2a: Method A

[0111] A 250 mL round bottom Schlenk flask equipped with a stir bar was charged with complex 1, (sIMes)(PCy3)(Cl)2Ru═CHPh, (10.0 g; 11.8 mmol). The flask was capped, sparged with argon for 15 minutes, and charged with anhydrous CH2Cl2 (118 mL) via cannula. 2-(3-butenyl)pyridine (2.4 g, 17.7 mmol) was then added via syringe and the reaction mixture was heated to 40° C. for 5-6 hours. The reaction mixture was concentrated to dryness and the residue triturated with degassed, chilled methanol. The solid was collected on a frit and washed with chilled methanol (2×25 mL) to give catalyst 2a, (sIMes)(Cl)2Ru(CH(CH2)2—C,N-2-C5H4N)—Cs, (5.6 g; 9.4 mmol) as a pale green solid upon drying. Yield: 80%.

example 2

Synthesis of Catalyst 2a: Method B

[0112] In the glove box a vial was charged with 2-(3-butenyl)pyridine (24 mg, 0.18 mmol) and CH2Cl2 (2 mL). Complex 3, (sIMes)(py)2(Cl)2Ru═CHPh, (86 mg; 0.12 mmol) was then added as a solid and the reaction allowed to stir at room temperature for 30 minutes. The volatiles were removed under vacuum and the residue triturated with hexanes. The solid was collected, washed with hexanes (2×1 mL) and dried under vacuum to give catalyst 2a, (sIMes)(Cl)2Ru(CH(CH2)2—C,N-2-C5H4N)—C, (60 mg; 0.10 mmol) as a pale green solid upon drying. Yield: 85%. 1H NMR (CD2Cl2): δ 18.46 (t, 3JHH=2.7 Hz, 1 H, Ru═CH), 7.64 (d, 3JHH=4.8 Hz, 1 H, Py), 7.52 (t, 3JHH=7.2 Hz, 1 H, Py), 7.14 (d,3JHH=7.8 Hz, 1H, Py), 7.07 (s, 4 Mes), 6.99 (t, 3JHH=6.9 Hz, 1 H, Py), 4.09 (s, 4 H, sIMes), 3.55 (t, 3JHH=5.7 Hz, 2H, CH2-Py), 2.50 (s, 12 H, Mes-CH3), 2.41 (s, 6 H, Mes-CH3), 1.70 (m, 2 H, Ru═CH—CH2). 13C{1H} NMR (CD2Cl2): δ 339.18 (Ru═CHCH2), 216.52 (Ru—C(N)2), 162.64, 158.34, 149.54, 13...

example 3

Conversion of Catalyst 2a to Catalyst 2b

[0113] In the glove box, a 0.1 M solution of catalyst 2a in CD2Cl2 was prepared and transferred to an NMR tube, which was capped and taken out of the glove box. The NMR tube was left in an oil bath at 40° C. and the reaction was monitored by 1H NMR spectroscopy. The ratio of 2b to 2a in the mixture was 30 / 70 after 24 hours; 60 / 40 after 48 hours; 70 / 30 after 72 hours; and 78 / 22 after 96 hours.

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Abstract

The invention provides novel organometallic complexes useful as olefin metathesis catalysts. The complexes have an N-heterocyclic carbene ligand and a chelating carbene ligand associated with a Group 8 transition metal center. The molecular structure of the complexes can be altered so as to provide a substantial latency period. The complexes are particularly useful in catalyzing ring closing metathesis of acyclic olefins and ring opening metathesis polymerization of cyclic olefins.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119(e)(1) to Provisional U.S. Patent Applications Ser. No. 60 / 557,742, filed Mar. 29, 2004, and Ser. No. 60 / 604,158, filed Aug. 23, 2004. The disclosures of the aforementioned provisional patent applications are incorporated by reference herein.TECHNICAL FIELD [0002] This invention relates generally to olefin metathesis catalysts, and more particularly pertains to new Group 8 transition metal complexes that are useful as latent olefin metathesis catalysts. The invention has utility in the fields of catalysis, organic synthesis, and organometallic chemistry. BACKGROUND OF THE INVENTION [0003] Olefin metathesis catalysis is a powerful technology, which in recent years has received tremendous attention as a versatile method for the formation of carbon-carbon bonds and has numerous applications in organic synthesis and polymer chemistry (R. H. Grubbs, Handbook of Metathesis, Vol. 2 and 3; Wi...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C07F15/00C08F4/80C08G61/06
CPCC07F15/0046C08F132/08C07C67/333C08G61/06C07D493/10C08G61/02C08G2261/11C08G2261/3325C08G2261/418
Inventor UNG, THAYSCHRODI, YANNTRIMMER, MARK S.HEJL, ANDREWSANDERS, DANIELGRUBBS, ROBERT H.
Owner CALIFORNIA INST OF TECH
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