Suzuki coupling agents

Recently, synthesis of the 4-arylindole portion of the antitumor agent diazonamide has been achieved starling from 3-bromo-2-methylnitrobenzene via Suzuki coupling and the Batcho reaction.67b... 

A synthesis of the immunosuppressive agent undecylprodigiosine involved a Suzuki coupling between 57 and triflate 62 to give tripyrrole 63 [57]. The corresponding Stille reaction was unsuccessful... 

The Suzuki coupling of 44 was utilized to prepare 5-substituted uracils as potential antiviral agents [21, 22]. Adduct 45, derived from 44 and 2-bromo-3-methylthiophene, was transformed to the corresponding uracil 46 via acidic hydrolysis. Conveniently, reversal of the coupling partners also resulted in formation of adduct 45, assembled from the Suzuki coupling of 5-bromo-2,4-di-f-butoxypyrimidine (43) and 3-methyl-2-thiopheneboronic acid. 

Suzuki, Y., Maekawa, Z., Hamada, H., Yokoyama, A. and Sugihara, T. (1993). Influence of silane coupling agents on interlaminar fracture in glass fiber fabric reinforced unsaturated polyester laminates. J. Mater. Sci. 28, 1725-1723. 

Milkiewicz et al. <2003TL4257> prepared a series of novel tetrasubstituted furo[3,2-/ ]pyrroles from the methyl or ethyl 3-bromo-2-phenylfuro[3,2-3]pyrrole-5-carboxylate 336. The compounds 336 were subjected to a Suzuki coupling with 4-chlorophenylboronic acid to form 337, which was treated with a variety of alkylating agents to afford the corresponding esters 338. The esters were then saponified to acids 339 (Scheme 34). 

The Hiyama Coupling is the palladium-catalyzed C-C bond formation between aryl, alkenyl, or alkyl halides or pseudohalides and organosilanes. This reaction is comparable to the Suzuki Coupling and also requires an activating agent such as fluoride ion or a base. 

Keywords Oxazolines Direct Stille and Suzuki coupling Diisopropylcarbo-diimide cyclization Chemotherapeutic agent Anti-HIV activity... 

The 2-aryloxazolines (v) have been synthesized under microwave activation by the direct Stille and Suzuki cross coupling reactions of l,3-oxazolidine-2-thiones (OZT) (iv) using (vi) as the coupling agent [14]. 

Suzuki and other couplings. This Suzuki coupling has been applied to preparation of 2- and 4-arylpyridines. For a synthesis of styrenes the coupling of arenediazonium salts with potassium vinyltrifluoroborate has been developed. The latter is a. stable and efficient vinylating agent. 

Maekawa er al. reported that a series of co-oxazolylalkanoic acid derivatives as antidiabetic agents, promoting the glucose-dependent secretion of insulin. (o-(5-Oxazolyl)alka-noates 27, the key intermediates for the synthesis of target compounds, were prepared via Suzuki coupling of substituted 2-chlorooxazole with phenylboronic acid [34]. 

Reaction of chloromethyl-PS with the alkoxide of Solketal followed by hydrolysis of the aeetonide affords a diol linker 5y [252,253] to which aldehydes can be anchored in the presence of acid and a dehydrating agent. An application of this resin involved anchored bromobenzoic acids that were subjected to Suzuki couplings and products cleaved by heating in 3 M HCl-dioxane (1 1) [254],... 

Instead of aryl halides, arenediazonium salts are also excellent arylating agents in the Suzuki coupling, although more hindered arylboronic acids did not react The reaction is catalysed by several sources of ligand-free palladium such as Pd(OAc)2, Pd2(dba)3 and Pd/C at room temperature in dioxane without any added base [98]. Use of potassium aryl trifluoroborate salts also allowed the introduction of more sterically hindered aryl groups [99]. 

The antiviral bromoindole alkaloid dragmacidin F and the potent natural antitumor agent (-f-)-dynemicin A involve a Suzuki coupling in one of the key carbon-carbon bond-forming steps (Figure 10.1) [8, 9). Further examples of industrially prepared fine chemicals involving palladium-catalyzed cross-coupling... 

Hu has shown that Suzuki couplings can take place at ambient temperature. Here, air-sensitive Ni(COD)2 can be used with either PPhs or PCys (Equation 2.7). Alternatively, air-stable [Ni(PPh3)2Cl2] may be employed as catalyst, although the use of n-BuLi as reducing agent is required (16). 

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