The palladium-catalysed cross-coupling reaction of lithium polyfluorophenyltrimethoxyborates with 4-fluoroiodobenzene

Li[C6F5B(OMe)3], Li[C6HF4B(OMe)3] (all three isomers) and Li[3,4,5-C6H2F3B(OMe)3] are the first examples of polyfluorophenyltrimethoxyborate salts which have been applied as reagents to Pd-catalysed cross-coupling reactions. A series of polyfluorinated biphenyls C6H5−nFn-C6H4F-4′ were obtained from Li[C6H5−nFnB(OMe)3] and the model substrate 4-FC6H4I in the presence of Pd catalysts. The influence of the number and the position of fluorine atoms in the polyfluorophenyltrimethoxyborate salts on the reactivity in the coupling reaction was elucidated.