Table 1. Optimization of Reaction Conditions^a.

entry	catalyst	Ag salt	Cu salt	solvent	yield (%) of 3a
1	[Cp*IrCl2] 2	AgSbF6	Cu(OAc)2·H2O	DCE	35
2	[Cp*RhCl2] 2	AgSbF6	Cu(OAc)2·H2O	DCE	41
3	(PPh3)3RuCl2	AgSbF6	Cu(OAc)2·H2O	DCE	trace
4	RuCl3	AgSbF6	Cu(OAc)2·H2O	DCE	NRb
5	[Ru(p-cymene)Cl2]2	AgSbF6	Cu(OAc)2·H2O	DCE	45
6	[Ru(p-cymene)Cl2]2	AgPF6	Cu(OAc)2·H2O	DCE	26
7	[Ru(p-cymene)Cl2]2	AgBF4	Cu(OAc)2·H2O	DCE	29
8	[Ru(p-cymene)Cl2]2	AgOTf	Cu(OAc)2·H2O	DCE	30
9	[Ru(p-cymene)Cl2]2	AgOAc	Cu(OAc)2·H2O	DCE	35
10	[Ru(p-cymene)Cl2]2	Ag2CO3	Cu(OAc)2·H2O	DCE	37
11	[Ru(p-cymene)Cl2]2	AgSbF6	CuCO3	DCE	40
12	[Ru(p-cymene)Cl2]2	AgSbF6	CuBr2	DCE	36
13	[Ru(p-cymene)Cl2]2	AgSbF6	CuO	DCE	39
14	[Ru(p-cymene)Cl2]2	AgSbF6	Cu(OAc)2·H2O	DCM	40
15	[Ru(p-cymene)Cl2]2	AgSbF6	Cu(OAc)2·H2O	PhMe	31
16	[Ru(p-cymene)Cl2]2	AgSbF6	Cu(OAc)2·H2O	MeOH	trace
17c	[Ru(p-cymene)Cl2]2	AgSbF6	Cu(OAc)2·H2O	DCE	66
18d		AgSbF6	Cu(OAc)2·H2O	DCE	NRb
19e	[Ru(p-cymene)Cl2]2		Cu(OAc)2·H2O	DCE	NRb
20f	[Ru(p-cymene)Cl2]2	AgSbF6		DCE	52

^aReaction conditions: 1a (0.2 mmol), 2a (0.3 mmol, 1.5 equiv), catalyst (2.5 mol %), silver salt (10 mol %), and copper salt (20 mol %) in 3 mL solvent at 100 °C for 12 h.

^bNo reaction.

^c3.5 mol % [Ru(p-cymene)Cl₂]₂ in combination of 30 mol % AgSbF₆ were used. Reaction time was extended to 21 h.

^dNo Ru catalyst was used.

^eNo silver salt was used.

^fNo copper salt was used, while 3.5 mol % [Ru(p-cymene)Cl₂]₂ in combination of 30 mol % AgSbF₆ were used for 21 h.