Optimization of the reaction conditions^a.

Entry	Catalyst	Additive	Yieldb (%)
1	None	NaOAc	15
2	FeCl2	NaOAc	41
3	Fe(acac)3	NaOAc	32
4	CuBr	NaOAc	11
5	CuBr2	NaOAc	Trace
6	PdCl2	NaOAc	36
7	Pd(OAc)2	NaOAc	35
8	Pd2(dba)3	NaOAc	40
9	Pd(PPh3)2Cl2	NaOAc	60
10	Pd(PCy3)2Cl2	NaOAc	43
11	Pd(PPh3)2Cl2	None	10
12	Pd(PPh3)2Cl2	PivONa	35
13	Pd(PPh3)2Cl2	PhCO2Na	13
14	Pd(PPh3)2Cl2	NaOAc	Tracec
15	Pd(PPh3)2Cl2	NaOAc	67d

^aReaction conditions: 1b (0.3 mmol), 4a (0.2 mmol), catalyst (0 or 10 mol%), additive (0 or 1 equiv.), MeCN (2 mL), 60 °C, 12 h, in a sealed tube, under Ar.

^bIsolated yields; dr > 19 : 1.

^cReaction was run at 40 °C.

^dNaOAc (0.5 equiv.) was used.