Example 7
Catalysis of the Suzuki Reaction
The coupling of bromobenzene and benzeneboronic acid (dihydroxyphenylborane) to biphenyl was investigated. The typical reaction conditions were based on studies of the Suzuki reaction which were taken from the current literature.
To carry out the Suzuki cross-coupling, a mixture of bromobenzene and 1.2 equivalents of benzeneboronic acid in toluene was admixed with 2 equivalents of bis(N-pivaloyl-N′-butyl-benzamidine)palladium(II) chloride auxiliary base and as the catalyst. The reactions were carried out at from 85 to 110° C. To monitor the progress of the reaction, samples were taken regularly for was chromatography (GC). After from 1 to 72 hours, the reactions were terminated. The product yields were determined by GC using the internal standard diethylene glycol di-n-butyl
Table 2 summarizes the coupling experiments of bromobenzene and benzeneboronic acid to give biphenyl under bis(N-pivaloyl-N′-butylbenzamidine)palladium(II) chloride catalysis.
