Carbon coupling reactions

I 8 Pincer Complexes with Saturated Frameworks Synthesis and Applications 

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Polymerization by G—G Goupling. An aromatic carbon—carbon coupling reaction has been employed for the synthesis of rigid rod-like polyimides from imide-containing dibromo compounds and aromatic diboronic acids ia the presence of palladium catalyst, Pd[P(CgH )2]4 (79,80). 

Carbon-carbon and non-carbon-carbon coupling reactions... 

A zinc-mediated carbon-carbon coupling reaction can be carried out on the metallated form of (t-butyldimethylsilyl)(2-pyridylmethyl)amine, formed in reaction with dimethylzinc. The isolated dimeric species can be reacted with further dimethyl zinc to give bis(methylzinc)-l,2-dipyridyl-l,2-bis(t-butyldimethylsilylamido)ethane, which contains two N3C coordinated zinc centers.89... 

Scheme 1.3 Pd(0) NP-catalyzed carbon-carbon coupling reactions in ILs A[36,94, 102, 103,113,...

The first examples of the use of palladium as a catalyst for carbon-carbon coupling reactions were reported almost thirty years ago [14], and over recent decades a massive effort has been devoted to the extension of the scope of palladium-catalyzed reactions. Organic and organometallic chemists have received extensive input from palladium-coordination chemistry in the task of understanding the mechanisms behind these efficient synthetic procedures [14]. 

Cyanation of aromatic hydrocarbons, also a carbon-carbon coupling reaction, is achieved in the case of anthracene in MeCN-Et4NCN to yield 54% 9,10-dicyanoanthracene [165]. The cyanation is simplified when it is carried out in an emulsion system (aqueous sodium cyanide, dichloromethane, and TBAHSO4). Its synthetic utility in this mode has been demonstrated for the preparation of 4-alkoxy-4-cyanobiphenyls, a class of liquid crystals [166]. 

The Kolbe electrolysis has been used by Schafer and coworkers to synthetize substituted furans or pyrrolidines in good yields by a carbon-carbon coupling reaction after co-oxidations of 6-alkenoic acids and various carboxylic acids [4, 5, 20, 21] (Schemes 2 and 15). In Scheme 15, the... 

The reduction of the bis(phenylethynyl)silanes 245a-f into a two-fold radical anion, followed by an /wtramolecular carbon-carbon coupling reaction, was introduced by Tamao and coworkers to generate variously substituted 2,5-dilithio-3,4-diphenylsiloles of type... 

As the last example of C-C bond-formation reactions catalyzed by alkaline earth hydroxides, we mention the recently reported a-arylation of diethyl malonate in the presence of a palladium catalyst and a base in a separate phase 299). The arylation of carbonyl compounds is a carbon-carbon coupling reaction between an aryl halide and an enolate, which is usually catalyzed by palladium salts in the presence of an appropriate base (300,301). The arylation of diethyl malonate with bromobenzene (Scheme 48) was performed with tetrachloropalladate as the... 

The expected compound in the carbon-carbon coupling reaction of 279 with 1-hexyne was found in only minor amounts (Equation 100). The major product of this reaction is the bicyclic compound 280 (no yield given) <2000TL8741>. 

Reactions other than Lewis acid-base associations/dissociations are frequently observed wit donor molecules, leading notably to solvolysis, oxygen or sulfur abstraction, insertion reaction and carbon-carbon coupling reactions. The tendency to form metal-element multiple bonds i remarkable in this respect the activation of dinitrogen by tantalum or niobium is unique. Th formation and chemistry of constrained reactive metallacycles open another promisin fast-developing area, on the frontier with organometallic chemistry. 

The aerobic oxidation of methane in water catalyzed by [Pt(Mebipym)Cl2] [PV2Mo1004o]5 (Mebipym = N-methy-2,2 -bipyrimidine) complex supported on Si02 was reported [149]. The conjugation of [PV2Mo1004o]5 to a known Pt2 + -bipyrimidine complex by electrostatic interaction could fadlitate the oxidation of the Pt2 + intermediate to a Pt4 + intermediate by 02, resulting in the catalytic aerobic oxidation of methane to methanol in water and then surprisingly further to acetaldehyde via a carbon-carbon coupling reaction. 

Directed coupling reactions, where no cross-coupling may occur, requires the reagents derived from the appropriate synthons to be ionically different at the reactive site. The carbon-carbon coupling reaction to form hept-l-ene (Expt 5.8), illustrates the importance of selecting the reactive, and readily available, allyl bromide (cationic site) with butylmagnesium bromide (anionic site) (A), rather than the other alternative (B). 

Transition-metal-catalyzed synthesis of poly(arylene)s via carbon-carbon coupling reactions was started by Yamamoto et al. three decades ago [52,53] since then various carbon-carbon bond formation processes with transition-metal catalysts have been applied to polycondensation [54-57]. In recent years, Buchwald et al. and Hartwig et al. developed Pd-catalyzed amination and etherification of aromatic halides by using bulky, electron-rich phosphine ligands [58-60], and this chemistry has been applied to polycondensation for... 

Essentially, two types of unsaturated bifunctional compound display the capability of being condensed in high yield, via a transition metal-catalysed carbon-carbon coupling reaction, into their requisite generic high molecular weight polymers plus a small molecule non-conjugated acyclic dialkenes and haloaromatic derivatives. 

Polycondensation via Carbon-Carbon Coupling Reactions Involving Haloarene Derivatives... 

Marcetta Darensbourg, Texas A M University Looking at carbon-carbon coupling reactions as mediated by transition metals. The nickel sites serve as the catalyst. 

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