Homocoupling and Oxidation of the Carbon Nucleophile

Transfer of Aryl Croups from the Phosphine Ligand 

This unwanted side reaction can be suppressed by keeping the amount of catalyst as small as possible, by using sterically demanding trialkyl phosphine ligands, by conducting the reaction in solvents of low polarity, such as CH2CI2 (instead of THF or DMF), or by using phosphine-free catalysts [23, 38, 62,132-134], 

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