Cross-coupling Of Grignard Reagents Research Articles

Iron-Catalyzed Cross-Coupling Reactions of Alkyl Grignards with Aryl Chlorobenzenesulfonates.

Aryl sulfonate esters are versatile synthetic intermediates in organic chemistry as well as attractive architectures due to their bioactive properties. Herein, we report the synthesis of alkyl-substituted benzenesulfonate esters by iron-catalyzed C(sp2)–C(sp3) cross-coupling of Grignard reagents with aryl chlorides. The method operates using an environmentally benign and sustainable iron catalytic system, employing benign urea ligands. A broad range of chlorobenzenesulfonates as well as challenging alkyl organometallics containing β-hydrogens are compatible with these conditions, affording alkylated products in high to excellent yields. The study reveals that aryl sulfonate esters are the most reactive activating groups for iron-catalyzed alkylative C(sp2)–C(sp3) cross-coupling of aryl chlorides with Grignard reagents.

Copper-catalyzed oxidative homo- and cross-coupling of Grignard reagents using diaziridinone.

Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)–C(sp3) coupling.

Oxidative Coupling Reactions of Grignard Reagents with Nitrous Oxide

Catalysis with laughing gas: N2O in combination with transition-metal catalysts allow the oxidative homo- and cross-coupling of Grignard reagents. The reactions can be performed under mild conditions despite the inert character of N2O.

Transition-metal-free Oxidative Coupling Reactions for the Formation of C–C and C–N Bonds Mediated by TEMPO and its Derivatives

The application of nitroxides for the development of new synthetic methods and their implementation in polymer chemistry, material science and beyond is one of the major research topics in our laboratory in the institute of organic chemistry at the WWU Münster. This short review focuses on our recent progress towards nitroxide-based transition-metal-free oxidative coupling reactions. The demand for organic surrogates for transition metals in such transformations is in our eyes unquestionable, since environmental and economic issues have become progressively more important in recent years. For this purpose, the 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO) is shown to be a highly efficient oxidant for the homo- and cross-coupling of Grignard reagents. This powerful C-C bond forming strategy allows the generation of conjugated polymers from bifunctional Grignard reagents. Moreover, cross-coupling of alkynyl Grignard compounds and nitrones can be accomplished under aerobic atmosphere with catalytic amounts of TEMPO. It is also shown that TEMPO-derived N-oxoammonium salts can act as suitable oxidants for formation of C-N bonds between non-preactivated benzoxazoles and secondary amines under metal-free conditions.

ChemInform Abstract: Catalytic Double C—Cl Bond Activation in CH2Cl2 by Iron(III) Salts with Grignard Reagents.

AbstractA dinuclear amine‐bis(phenolate) iron complex (I) or FeCl3 are used in the cross‐coupling of Grignard reagents with dichloromethane to give diarylmethanes and diarylethanes.

Catalytic Double C-Cl Bond Activation in CH2Cl2 by Iron(III) Salts with Grignard Reagents

Cross-coupling of Grignard reagents with dichloromethane is achieved using iron(III) catalysts. Aryl- and benzylmagnesium bromides show a range of activity toward double C―Cl bond activation resulting in the insertion of methylene fragments between two equivalents of the nucleophilic partner.

Cross-coupling of Grignard reagents with alkyl halides or tosylates by the use of nickel or palladium containing perovskite

Nickel and palladium-containing perovskites, LaFe 0.8Ni 0.2O 3 (LFNO) and LaFe 0.95Pd 0.05O 3 (LFPO), could be employed as effective catalyst sources for the cross-coupling of nonactivated alkyl halides and tosylates with Grignard reagents in the presence of conjugated dienes. The reaction proceeded efficiently at room temperature or below using only ca. 1 mol % of catalysts with respect to Ni or Pd and the perovskites were reused without considerable loss of activity.

ChemInform Abstract: Nickel-Mediated Cross-Coupling of Unactivated Neopentyl Iodides with Organozincs.

(dppf)NiCl 2 catalyzes the cross-coupling of unactivated primary neopentyl iodides with diorganozinc regents. The zinc nucleophiles are formed by the treatment of ZnCl 2 .dioxane with 2 mol equiv of a Grignard reagent in an ethereal solvent. The cross-coupling works optimally for diorganozincs formed from aryl chlorides or CH 3 MgCl. Use of aryl bromides can cause reduction and/or reductive dimerization of the electrophile. The analogous reaction with (CH 3 ) 2 CuMgCl in either the presence or the absence of Group 10 metal catalysts filed to afford reasonable yields of cross-coupled products. The diorganozinc methodology overcomes many of the side reactions observed with the (dppf)NiCl 2 -mediated cross-coupling of Grignard reagents

Palladium-catalysed Grignard cross-coupling using highly concentrated Grignards in methyl-tetrahydrofuran

The cross-coupling of Grignard reagents at 5 molar concentration in methyl-tetrahydrofuran with no added reaction solvents can be achieved with the appropriate matching of catalyst to substrate, significantly reducing solvent use when compared to a typical protocol in tetrahydrofuran. Me-THF was also used in an improved microwave accelerated synthesis of the [Pd(L)Cl2] pre-catalysts from sodium tetrachloropalladate in very high yield.

Cross-coupling of alkyl halides with Grignard reagents using nickel and palladium complexes bearing η3-allyl ligand as catalysts

The cross-coupling of Grignard reagents with alkyl bromides and tosylates has been achieved by the use of eta(3)-allylnickel and eta(3)-allylpalladium complexes as catalysts.

Iron-Containing Ionic Liquid as Catalyst for Cross-Coupling of Grignard Reagents with Alkyl Halides

Iron-Containing Ionic Liquid as Catalyst for Cross-Coupling of Grignard Reagents with Alkyl Halides

Palladium‐Catalyzed Cross Coupling of Grignard Reagents with in situ‐Derived Enol Phosphates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Palladium-catalyzed cross coupling of Grignard reagents with in situ-derived enol phosphates

A useful, one-pot protocol has been developed for the conversion of enolizable ketones to alkylated or arylated olefins by Pd-catalyzed cross coupling of in situ-generated enol phosphate intermediates with Grignard reagents.

A General Strategy for the Synthesis of Conjugated Polymers Based upon the Palladium-Catalysed Cross-Coupling of Grignard Reagents with Unsaturated Halides

Palladium-catalysed cross-coupling between aromatic bis-organomagnesium reagents and aromatic dihalides has been experimentally evaluated as a general methodology for the synthesis of soluble conjugated polymers such as poly(p-phenylene)s 6 and 7, poly(p-terphenylenevinylene) 8, poly(phenylenethiophene) 9 and poly(phenylenepyridine) 10. Appropriate experimental conditions were first found in model reactions and then applied to the synthesis of polymers. Molecular mass values were determined both by GPC and by MALDI-TOF spectrometry. The latter technique also permitted accurate determination of the terminal groups of the polymeric chains. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Homo coupling, disproportionation and cross coupling of alkyl groups. Role of the transition metal catalyst

Silver is an effective catalyst for the homo coupling of the Grignard reagent and alkyl halide when both alkyl groups are the same. Copper(I) catalyzes the cross coupling of Grignard reagents and alkyl bromides when carried out in tetrahydrofuran solutions at low temperatures. Facile vinylation of the Grignard reagent can be achieved with alkenyl bromides using an iron catalyst. Oxidation–reduction concepts are important in the formulation of these catalytic processes.

Reactions of organic halides with organometallic compounds and terminal acetylenes catalyzed by palladium complexes

The results of the investigation of the cross-coupling of organometallic compounds and terminal acetylenes with organic halides catalyzed by transition metal complexes are generalized and analyzed. The influence of different factors on the rate and selectivity of catalytic cross-coupling is discussed. A detailed mechanism of the cross-coupling of Grignard reagents with organic halides is suggested. The cross-coupling reaction involving organotin compounds proceeds under very mild conditions in the presence of a ligand-free Pd catalyst. Examples of using catalytic cross-coupling of organic halides with organomagnesium, organozinc, and organotin compounds are presented.

Recent Developement of Polymerization Using Transition Metal Complexes as Catalyst

Recent studies on polymerization using transition metal complexes as catalyst are reviewed. Ti, W, and Ru complexes catalyze ring opening metathesis polymerization of cyclic olefins such as norbornene and cyclooctene to give the corresponding polymers. Living polymerization is achieved in many cases. Structures and reactivities of cyclopentadienyl complexes of Ti, Zr, and Hf are investigated in order to elucidate reaction mechanism of olefin polymerization catalyzed by Kaminsky system. Transition metal complex catalyzed synthetic organic reactions such as carbonylation of organic halides, arylation of olefins as well as cross-coupling of Grignard reagents with organic halides have been applied to preparation of various polymers. Coupling reaction of aryl halides promoted by Ni complex is developed to preparation of π-conjugated polymers which show interesting electrical and optical properties.

Synthesis of unsaturated sulfides via cross-coupling of Grignard reagents with allylic electrophiles with simultaneous incorporation of sulfur into the metal-carbon bond

Two-component catalysts based on Pd(acac)2 or PdCl2 and Ph2P permit one to carry out the regioselective cross- coup ling of isoprenylmagnesium bromide with allyl ethers and esters, allyl halogenides, involving the simultaneous insertion of elemental sulfur into the metal-carbon bond, which results in the formation of higher order allyl sulfides, which are not easily accessible (by other means).

Synthesis of 2-Substituted Oxazoles by Cross-Coupling of Grignard Reagents with 2-(Methylthio)-oxazoles Employing Transition Metal-Phosphine Catalysis

Synthesis of 2-Substituted Oxazoles by Cross-Coupling of Grignard Reagents with 2-(Methylthio)-oxazoles Employing Transition Metal-Phosphine Catalysis

Nickel-complex-catalyzed cross-coupling of grignard reagents with 2-halogenobenzothiazoles

2-Halogenobenzothiazoles undergo C-C cross-coupling reaction with Grignard reagents in the presence of Ni(II)-phosphine complexes. The reaction is considerably influenced by the nature of the phosphine bonded to Ni(II) and the halogen in the halogenobenzothiazole. Particularly efficient catalysts are 2-chlorobenzothiazole coordinated nickel-complexes, NiBr 2(H 2O)(2-Cl-BT), NiBr 2(2-Cl-BT)PMe 3, NiBr 2,(2-Cl-BT)PCy 3 and complex NiBr 2(DMSO)PMe 3, which all are here reported for the first time. A possible mechanism for the catalytic activity exhibited by the nickel-complexes in the C-C cross-coupling of 2-halogenobenzothiazoles with Grignards is also reported.