Table 1. Optimization of the Reaction Condition of Benzo[a]phenazin-5-ol with Diphenyl Acetylene^a.

entry	catalyst	oxidant	solvent	yield (%)b
1	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	toluene	14c, 30
2	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	Cl-benzene	40
3	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,4-dioxane	10
4	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	t-AmOH	20
5	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	CH3OH	18
6	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	DMF	30
7	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,2-DCE	72
8	[RuCl2(p-cymene)]2	Cu(OAc)2	1,2-DCE	68
9	[RuCl2(p-cymene)]2	AgOAc	1,2-DCE	45
10	[RuCl2(p-cymene)]2	Ag2CO3	1,2-DCE	25
11	[RuCl2(p-cymene)]2	K2S2O8	1,2-DCE	18
12	[RuCl2(p-cymene)]2	PhI(OAc)2	1,2-DCE	trace
13d	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,2-DCE	28
14	[RuCl2(p-cymene)]2	−	1,2-DCE	0
15e	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,2-DCE	65
16f	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,2-DCE	50
17g	[RuCl2(p-cymene)]2	Cu(OAc)2·H2O	1,2-DCE	10
18	RuCl2·5H2O	Cu(OAc)2·H2O	1,2-DCE	trace
19	[RhCp*Cl2]2	Cu(OAc)2·H2O	1,2-DCE	60
20g	Pd(OAc)2	Cu(OAc)2	DMF	trace

^aReaction conditions: 1a (0.3 mmol), 2a (0.3 mmol), catalyst (5.0 mol %), additive AgSbF₆ (20 mol %), and oxidant (1 equiv) in the indicated solvent (2.0 mL) at reflux or 110 °C for 12 h under air.

^bIsolated yield.

^cUnder nitrogen.

^dOxidant (0.5 equiv).

^eKPF₆ was employed instead of AgSbF₆.

^fAgBF₄ was employed instead of AgSbF₆.

^gWithout additive.