Grubbs/hoveyda olefin metathesis

October 4 th

Grubbs/hoveyda olefin metathesis

R5 and R6 are each mesityl; R7 and R8 are each H. CH3 SO2— ; Calkylsulfinyl radicals e. The novel compounds of the general formula 1 are obtained by reacting preligands of the formula 2 with ruthenium complexes of the formula 3: In a preferred embodiment of the reaction, ruthenium complexes of the formula 3 in which the radicals R9 and R10 form a ring system for example an indenylidene system are used.

In a further preferred embodiment of the reaction, compounds of the general formula 2 in which the substituents a, b, c and d have the meanings given in claim 9 are used. The invention therefore further provides a compound of the formula 2 where, in a particular embodiment, R3, a, b, c and d have the meanings given in claim 1; and R1 is Calkyl, Ccycloalkyl, Caralkyl, aryl; R2 is H, Calkyl, Ccycloalkyl, Caralkyl, aryl; R11 and R12 are each, independently of one another, H, Calkyl, if appropriate substituted by one or more halogens, or aryl, if appropriate substituted by one or more halogens or Calkyl.

Preference is given here to the compounds of the formula 2, in which R1 is Calkyl, Ccycloalkyl, Caralkyl, aryl; R2 is H, Calkyl, Ccycloalkyl, Caralkyl, aryl; R11 and R12 are each, independently of one another, H, Calkyl, if appropriate substituted by one or more halogens, or aryl, if appropriate substituted by one or more halogens or methyl.

Particular preference is given to the compounds of the formula 2 in which R1 is methyl, cyclohexyl, benzyl, phenyl; R2 is H, methyl, cyclohexyl, benzyl, phenyl; R11 is H; R12 is H or methyl.

Furthermore, the invention also encompasses, in further preferred embodiments, compounds of the formula 2 in which R3 has the meanings given in claim 1 and R1, R2, R11 and R12 have the meanings given in claim 8 and a, b, c, d can each be, independently of one another, H, —NO2, Calkyl, Calkoxy or phenyl, where phenyl may be substituted by a radical selected from the group consisting of Calkyl and Calkoxy; halogen; cyano; aryl or heteroaryl; monohalogenated or polyhalogenated aryl radicals or heteroaryl radicals e.

The ligands and complexes disclosed can occur as pure enantiomers or enantiomer pairs.

Ring-closing metathesis | Totally Microwave

The invention therefore encompasses not only any racemates but likewise the pure enantiomers which can transfer their asymmetry to a substrate during catalysis as a result of the asymmetric center.

An additional aspect of the invention is a process for carrying out metathesis reactions in which two compounds which each contain an olefinic double bond or one of the compounds contains at least two olefinic double bonds are reacted and in which one of the abovementioned compounds of the formula 1 is used as catalyst, and also a process for carrying out a ring-closing metathesis RCM or a cross methathesis CM in which a compound containing two olefinic double bonds as substrate and one of the compounds of the formula 1 as catalyst participate.

Examples which may be mentioned are halogens such as fluorine, chlorine, bromine or iodine. Examples which may be mentioned are tertiary phosphines containing aliphatic, cycloaliphatic and aromatic hydrocarbon radicals, e.

Preference is given to alkyl groups having from 1 to 6 carbon atoms, particularly preferably from 1 to 4 carbon atoms. Examples which may be mentioned are: Unless indicated otherwise, in the case of propyl, butyl, pentyl and hexyl, the definitions encompass all conceivable isomeric forms of the respective radicals.

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Thus, for example, propyl encompasses n-propyl and isopropyl, butyl encompasses isobutyl, sec-butyl and tert-butyl, etc. Preference is given to alkenyl groups having from 2 to 6 carbon atoms, particularly preferably from 2 to 4 carbon atoms.

Unless indicated otherwise, in the case of propenyl, butenyl, pentenyl and hexenyl, the definitions encompass all conceivable isomeric forms of the respective radicals.

Grubbs/hoveyda olefin metathesis

Thus, for example, propenyl encompasses 1-propenyl and 2-propenyl, butenyl encompasses 1- 2- and 3-butenyl, 1-methylpropenyl, 1-methylpropenyl, etc. Preference is given to alkynyl groups having from 2 to 6 carbon atoms, particularly preferably from 2 to 4 carbon atoms.

Unless indicated otherwise, in the case of propynyl, butynyl, pentynyl or hexynyl, the definitions encompass all conceivable isomeric forms of the respective radicals.

Thus, for example, propynyl encompasses 1-propynyl and 2-propynyl, butynyl encompasses 1- 2- and 3-butynyl, 1-methylpropynyl, 1-methylpropynyl, etc. Preference is given to alkoxy groups having from 1 to 6 carbon atoms, particularly preferably from 1 to 4 carbon atoms. Unless indicated otherwise, in the case of propoxy, butoxy and pentoxy, the definitions encompass all conceivable isomeric forms of the respective radicals.

Thus, for example, propoxy encompasses n-propoxy and isopropoxy, butoxy encompasses isobutoxy, sec-butoxy and tert-butoxy, etc. Unless indicated otherwise, the cyclic alkyl groups can be substituted by one or more radicals selected from the group consisting of methyl, ethyl, isopropyl, tert-butyl, hydroxy, fluorine, chlorine, bromine and iodine.

Unless indicated otherwise, the aromatics can be substituted by one or more radicals selected from the group consisting of methyl, ethyl, isopropyl, tert-butyl, hydroxy, fluorine, bromine and iodine.

It is advantageous to add CuCl to the reaction mixture. The reactants are generally used in stoichiometric amounts, but the more valuable component in each case can be used in a substoichiometric amount to increase the yield.

It can also be advantageous to generate the complex of the formula 3 in situ from other ruthenium compounds and ligand precursors, e. The metathesis catalysts of the formula 1 prepared by the ligand exchange reaction can be separated off from other reaction products which are insoluble in the reaction mixture by filtration of their solution and, after evaporation of the solution, obtained in pure form by chromatography or crystallization.

However, it is also possible to use the crude products or the catalysts generated in situ directly for carrying out metathesis reactions. The alkylation of phenols to form alkyl phenyl ethers is well known to those skilled in the art; it is usually carried out in solvents in the presence of basic substances by reaction with nucleophilic reagents.

Possible solvents are, for example, alcohols such as ethanol or aprotic polar solvents such as dimethylformamide.Advanced Fine-Tuning of Grubbs/Hoveyda Olefin Metathesis Catalysts: A Further Step toward an Optimum Balance between Antinomic Properties M.

The potential energy surfaces for the activation of Grubbs–Hoveyda-type precatalysts with the substrates ethene, propene, 1-hexene, and ethyl vinyl ether (EVE) have been probed at the density functional theory (DFT) (ML) level. Several new C–H-activated ruthenium catalysts for Z-selective olefin metathesis have been synthesized. Both the carboxylate ligand and the aryl group of the N-heterocyclic carbe. Highly active olefin metathesis catalysts were prepared by thermal spreading MoO and/or MoO(acac) on MWW zeolites (MCM, delaminated MCM) and on two-dimensional MFI (all in NH form). The catalysts' activities were tested in the metathesis of neat 1-octene (as an example of a longer chain olefin.

Bieniek, R. Bujok, M. Cabaj, N. Lugan, G. Lavigne, An Olefin Metathesis/Double Bond Isomerization Sequence Catalyzed by an In Situ Generated Ruthenium Hydride Species B. Schmidt, Eur.

J. Org. Chem.

Grubbs/hoveyda olefin metathesis

Read "Fast Olefin Metathesis at Low Catalyst Loading, Chemistry – A European Journal" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

Olefin Metathesis Grubbs Reaction. Olefin Metathesis allows the exchange of substituents between different olefins - a transalkylidenation.

Synthesis and characterization of Ru(II) phenylindenylidene olefin metathesis type complexes By YALEZO Ntsikelelo () B. Sc., B. Sc. (Honours) Chemistry (UFH) Being a dissertation submitted to the Faculty of Science and Agriculture in fulfilment of the requirements for the award of the degree of Master of Science in Chemistry of the. Olefin Metathesis Grubbs Reaction Organic Chemistry Portal Ring Opening Metathesis requires a strained ring to proceed Follows cross metathesis An example reaction of a . Advanced Fine-Tuning of Grubbs/Hoveyda Olefin Metathesis Catalysts: A Further Step toward an Optimum Balance between Antinomic Properties, Michał Bieniek, Robert Bujok, Maciej Cabaj, Noël Lugan, Guy Lavigne, Dieter Arlt, Karol Grela.

This reaction was first used in petroleum reformation for the synthesis of higher olefins (Shell higher olefin process - SHOP), with nickel catalysts under high pressure and high temperatures.

Tetrahedron 60 () – Olefin metathesis Robert H. Grubbs* The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA , USA.

Olefin metathesis has emerged as a key organometallic reaction for forming C¼C bonds to yield alkenes as well as alkynes.[1] second generation Grubbs-Hoveyda precatalysts bearing a che-lating aryloxide alkylidene unit were studied in detail.

It is known . FULL PAPER DOI: /chem Fast Olefin Metathesis at Low Catalyst Loading Lars H. Peeck, Roman D. Savka, and Herbert Plenio*[a] Abstract: Reactions of the Grubbs 3rd tive, conventional, O-Grubbs–Hoveyda plexes.

Ring Closing Metathesis