Table 1.

Screening of different metal catalysts for reacting p-iodotoluene with benzeneboronic acid.

Entry	Metal catalysts	Solvent	Base	Yielda (%)
1	Ni(NO3)2⋅6H2O	H2O	K2CO3	6
2	Ni(SO4)2⋅6H2O	H2O	K2CO3	3
3	NiCl2⋅6H2O	H2O	K2CO3	5
4	Ni(OAc)2	H2O	K2CO3	12
5	Co(OAc)2⋅6H2O	H2O	K2CO3	N.R
6	CoCl2⋅6H2O	H2O	K2CO3	N.R
7	FeCl3⋅6H2O	H2O	K2CO3	10
8	Ni-EDA-β-CD complex	H2O	K2CO3	79

Reaction status: phenylboronic acid, p-iodotoluene, base (with the ratio: 0.75:0.5:0.75), metal catalyst (5 mol%), and solvent (1 mL) undergo Argon.

^aYield determined by GC.