Suzuki crosscoupling reaction

Zheng, Y., Stevens, P.D. and Gao, Y. (2006) Magnetic nanopartides as an orthogonal support of polymer resins applications to solid-phase Suzuki crosscoupling reactions. Journal of Organic Chemistry, 71 (2), 537-542. 

Beilina F, Carpita A, Rossi R (2004) Palladium catalysts for the Suzuki Crosscoupling reaction an overview of recent advances. Synthesis 2419-2440 Bhattacharyya SJ (2000) Polymer-supported reagents and catalysts recent advances in synthetic applications. Comb Chem High Throughput Screening 3 65-92... 

Leadbeater NE, Pillsbury SJ, Shanahan E, Williams VA (2005) An assessment of the technique of simultaneous cooling in conjunction with microwave heating for organic synthesis. Tetrahedron 61 3565-3585 Lee CKY, Holmes AB, Ley SV, McConvey IF, Al-Duri B, Leeke GA, Santos RCD, Seville JPK (2005) Efficient batch and continuous flow Suzuki crosscoupling reactions under mild conditions, catalysed by polyurea-encapsulated palladium (II) acetate and tetra-n-butylammonium salts. J Chem Soc Chem Commun 2175-2177... 

The imidoyl chloride moiety of 5-chloro-l-alkyl-1,4-benzodiazepin-2-ones participates in Pd-catalyzed, Suzuki crosscoupling reactions, reacting with a range of functionalized aromatic boronic acids to provide an efficient and versatile approach to 5-aryl and 5-heteroaryl compounds (Scheme 19) <2003JOC2844>. This chemistry readily extends to 3-amino-substituted compounds that are orally bioavailable inhibitors of the aspartyl protease 7-secretase <2003BML4143>. 

Thus, for our present purposes a similar approach was followed using Suzuki cross-coupling reactions as the key steps in the synthesis of our target compounds. Symmetrically substituted compounds were synthesized in a twofold Suzuki crosscoupling reaction from commercially available p-substituted phenylboronic acids or esters and 4,4 -dibromobiphenyl or 4,4 -biphenyl-bis-boronic acid ester and a p-substituted arylhalide, respectively, using tetrakis (triphenylphosphino) palladium as catalyst together with cesium fluoride as base in dry tetrahydrofurane as shown in Scheme 8.1. The desired products were obtained in respectable yields after heating at reflux for 50 h. 

Arylboronic acids are readily available via transmetalation between ArSnMe3 and borane in THF. Consequently, a variety of arylpolyboronic acids is achievable from the stannanes previously synthesized by the SRN1 mechanism from ArCl or ArOH in around 80% yields [50, 51]. These arene di- and tri-boronic acids can be used as starting materials for the synthesis of polycyclic aromatic systems via double or triple Suzuki crosscoupling reactions [50, 51], as shown in Scheme 10.34 [51],... 

Many 6-alkylaminopurine nucleosides are important adenosine receptor antagonists, and acyclic nucleotide analogues derived from 6-dialkylaminopurines are strong antivirals, anti-neoplastic agents, and immunomodulators. Recently, several 6-(arylalkynyl)-, 6-(arylalkenyl)-, and 6-(arylalkyl)purines have been reported to exhibit cytokinine activity. Suzuki crosscoupling reactions of 9-benzyl-6-chloropurine with boronic acids have recently been reported to provide 6-substituted purines in moderate to excellent yields (Eq. (46)) [77]. 

Bis(pyrazolyl)borate copper complex 902 has been employed as a catalyst in homogeneous and heterogeneous styrene epoxidation reactions <2000CC1653>. Pyrazole palladacycles 903 have proved to be stable and efficient catalysts for Heck vinylations of aryl iodides <2000CG2053>. A hemilabile pyrazolyl-functionalized N-heterocyclic carbene complex of palladium(ll) such as 904 has been found to be an excellent catalyst for Heck and Suzuki crosscoupling reactions in ionic liquids <2006JOC426>. 

In one case, an unpurified sample of pyrrolyl-bisboronic ester 86, synthesized using conditions described by Masuda et al. [30], was readily engaged in a Suzuki crosscoupling reaction [29] with 5-bromoquinoline 85, giving the desilylated product 87 in 29% overall yield [39]. 

A -unsubstituted 4,5-dichloropyridazin-3(277)-one (109) fails to undergo Suzuki crosscoupling reactions. In order to synthesize N-2, unsubstituted 4,5-diarylpyridazin-3(2//)-ones (112) by Suzuki reaction, the temporary protection of the lactam moiety of 109 is essential. To achieve this a simple and efficient retro-ene-assisted Suzuki methodology has been developed by Ravina and co-workers which is based on 4,5-dichloro-2-(hydroxymethyl)pyridazin-3(277)-one (110) [61]. This pyridazin-3(2//)-one is easily available from 109 via reaction with formaldehyde. Interestingly, 110 reacts smoothly with arylboronic acids to afford directly the deprotected 4,5-diarylated pyridazin-3(2//)-ones (112) in high yields. The mechanism probably involves the formation of 4,5-diarylated-2-(hydroxymethyl)pyridazin-3(277)-ones (111), which subsequently lose formaldehyde by a retro-ene reaction induced by base or heat [62]. 

Table 2 Alkyl bromides and aryl-, vinyl-, and alkylboronic acids used in Suzuki crosscoupling reactions...

A mild TFA decumylation initiates the concluding transformations to obtain theiV-substituted saccharins. The sequence leading to 4,7-disubstituted saccharins is initiated by a BuLi/iodination protocol to give the required intermediate for a Suzuki crosscoupling reaction toward the final compound (eq 52). ... 

R. C. D. Santos, J. P. K. Seville, EfEdent batch and continuous flow Suzuki crosscoupling reactions under mild conditions, catalyzed by polyurea-encapsulated palladium(II) acetate and tetra-ti-butylammonium salts, Chem. Commun. 2005, 2175-2177. 

McNulty J, Capretta A, Wilson J, Dyck J, Adjabeng G, Robertson A (2002) Suzuki crosscoupling reactions of aryl halides in phosphonium salt ionic liquid under mild conditions. Chem Commun 2002 1986... 

The use of thallium(i) carbonate in palladium(0)-catalysed couplings was first investigated by Suzuki and coworkers for the preparation of iso-flavones. In the presence of aqueous thallium(i) carbonate, the desired product was formed in a shorter reaction time compared with use of other bases. Under anhydrous conditions the reaction time was increased fourfold, but the yield was only improved from 85% to 91%. In Scheme 20.19, representative examples of the application of thallium(i) carbonate to accelerate the Suzuki crosscoupling reactions are shown. ... 

Berree, F Girard-Le Bleis, P., and Carboni, B. (2002) Synthesis of the marine sponge alkaloid oroidin and its analogues via Suzuki crosscoupling reactions. Tetrahedron Lett., 43,4935-4938. 

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