Suzuki reaction coupling reaction

Suzuki Coupling Reaction Suzuki reaction is palladium-catalyzed cross-couphng between organoboronic acid and halides. Recently, newly developed catalysts and methods have broadened possible applications enormously, so that the scope of the reaction partners is not restricted to aryls but includes alkyls, alkenyls, and alkynyls. Potassium trifluoroborates and organoboranes or boronate esters may be used instead of boronic acids. Some pseudohaUdes (e.g., triflates) may also be used as coupling partners. 

Transition metal-catalysed reactions have emerged as powerful tools for carbon-carbon (C-C) bond formation [1], Cross-coupling reactions (Suzuki-Miyaura, Mizoroki-Heck, Stille, etc.) are recognised to be extremely reliable, robust and versatile. However, some other catalysed arylation reactions have been studied and have been reported to be very efficient [2]. In recent years, A -heterocyclic carbenes (NHC) have been extensively studied and their use as ligands for transition-metal catalysis has allowed for the significant improvement of many reactions [3]. This chapter highlights the use of NHC-bearing complexes in those arylation reactions. 

HCR Homogeneous catalytic reaction including hydrogenation, Heck coupling, and Suzuki reaction. 

Diazonium salts are another useful source of free radicals, and the formation of the reactive species can be achieved by reductive electrolysis or direct treatment with diazonium tetrafluoroborate salts [39]. By this route, several aryl derivatives could be introduced onto the nanotube sidewalls [40]. Aryl groups bearing halogen or alkyne functionalities are particularly interesting as they can be further reacted in Pd-catalyzed coupling reactions (Suzuki, Heck) or in click chemistry reactions to create products with great potential in materials science [41]. 

The arylation of support-bound arenes has mainly been performed using the Suzuki and Stille coupling reactions. Both reactions proceed smoothly with arenes and het-eroarenes such as furans, thiophenes, or pyridines. Examples of the arylation of het-eroarenes are presented in Chapter 15. 

Pizzirani D, Robert M, Recanatini M (2007) Domino Knoevenagel/Diels-Alder sequence coupled to Suzuki reaction a valuable synthetic platform for chemical biology. Tetrahedron Lett 48 7120-7124... 

Epoxidation, palladium-catalyzed cross-coupling (Stille, Suzuki reaction), peptide synthesis. 

Solid phase bromination of indole-2-carboxylic acids linked to Merrifield resin by pyridinium bromide perbromide gives 3-bromo derivatives that were subsequently coupled via Suzuki reactions [58]. 

Claisen-Schmidt condensation, and acetonylacetone cyclization Aryl coupling reactions (Suzuki, Heck, and Pd-exchanged mesoporous catalysts High activity and reusability avoiding the usual problem of Pd [184]... 

Suzuki A (2004) Organoborane Coupling Reactions (Suzuki Coupling) ProcJpn Acad 80 359. 

In 2006, be Gall et al. [67] presented a conceptually different approach for the synthesis of pulvinic acids, starting from commercial tetronic acid 87 (Scheme 1.12). The protocol involves application of Pattenden s arylidenylation by aroyl formates, iodination, and aryl coupling by Suzuki reaction. The utility of be Gall s method was exemplified by the synthesis of vulpinic (24) and pinastric (26) acid. 

The known approaches to perfluoroarylbenzothiophenes are generally based on the cross-couplings and reactions with organometallic reagents. For example, benzo[l,2-b 4,5-fe ]dithiophene 235 and -diselenophene 236, which are known p-channel semiconducting materials, were modified via palladium-catalyzed Suzuki-Miyaura coupling reaction. The reaction proceeded in moderate yields and gave compounds 237, 238 which can act as n-semiconductors [120]. 

Scheme 8 Boscalid synthesis via decarboxylative coupling and Suzuki reaction...

The Suzuki-Miyaura reaction involves the palladium-catalyzed cross-coupling between organoboron compounds and halides. In most cases, aryl halides are used as electrophiles, but recent developments have broadened the scope and alkyl, alkenyl, and alkynyl halides can be successfully used as reaction partners. Among C—C coupling reactions, Suzuki-Miyaura reaction has become one of the most appealing because the reactants are air stable, nontoxic and tolerant of a variety of functional groups. 

Vinylation can also be done by Pd-catalysed cross-coupling in which one component is used as a halide or triflate and the other as a stannane (Stille reaction) or boronic acid (Suzuki reaction). Entry 9, Table 11.3, is an example of the use of a vinylstannane with a haloindole. lndole-3-boronic acids, which can be prepared by mcrcuration/boration, undergo coupling with vinyl triflates (Entry 10). 

To date a number of reactions have been carried out in ionic liquids [for examples, see Dell Anna et al. J Chem Soc, Chem Commun 434 2002 Nara, Harjani and Salunkhe Tetrahedron Lett 43 1127 2002 Semeril et al. J Chem Soc Chem Commun 146 2002 Buijsman, van Vuuren and Sterrenburg Org Lett 3 3785 2007]. These include Diels-Alder reactions, transition-metal mediated catalysis, e.g. Heck and Suzuki coupling reactions, and olefin metathesis reactions. An example of ionic liquid acceleration of reactions carried out on solid phase is given by Revell and Ganesan [Org Lett 4 3071 2002]. 

In one case, an unpurified sample of pyrrolyl-bisboronic ester 78, synthesized using conditions described by Masuda and coworkers (2000JOC164), was readily engaged in a Suzuki cross-coupling reaction (95JOC7508) with 5-bromoquinoline 77, giving the desilylated product 79 in 29% overall yield (2002JCS(Pl) 1320). 

The mechanism " of the Suzuki reaction is closely related to that of the Stille coupling reaction, and is also best described by a catalytic cycle ... 

Of particular synthetic importance is the coupling of aryl- and hetarylboronic acids to aryl- and hetaryl halides (or triflates), allowing for a convenient synthesis of biphenyls, even sterically demanding derivatives such as 14, hetaryl phenyls and Zj/ -hetaryls. With appropriately disubstituted aromatic substrates, the Suzuki coupling reaction can be applied in the synthesis of polyphenylene materials. 

Heck, Suzuki, Stille, and Negishi coupling reactions... 

Scheme 5.2-18 Pd-catalyzed Suzuki cross-coupling reaction in a [BMIM][BF4] ionic liquid.

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