Cross-Coupling of ArN₂BF₄ with ArB(OH)₂

Significance

The cross-coupling reaction of arenediazonium tetrafluoroborate salts with boronic acids was achieved by using palladium(0)/barium carbonate as a catalyst. The reactions were carried out in the presence of 0.1-2.0 mol% of the catalyst to give the corresponding biaryl compounds in 77-98% yield (12 examples). The authors also reported the synthesis of unsymmetrical terphenyl in a one-pot process. The cross-coupling reaction of 4-iodobenzenediazonium tetrafluoroborate salt with phenyl boronic acid proceeded under base-free conditions to give 4-iodo­biphenyl. The subsequent cross-coupling reaction of 4-iodobiphenyl with (3,4-dimethoxyphenyl)boronic acid took place smoothly in refluxing meth­anol in the presence of aqueous Na₂CO₃ to afford unsymmetrical terphenyl in 92% yield.