Optimization of the reaction parameters.

Entry	Deviation from standard conditions	Yield (%)a
1	None	82 (80)b
2	1.5 equiv. of 2	74
3	1.1 equiv. of 2	63
4	Reaction at 70 °C	54
5	DCM instead of DCE	32
6	1,2-Dichlorobenzene instead of DCE	25
7	CH3CN, THF, 1,4-dioxane, and MeOH instead of DCE	n.r.
8	AgOAc (1 equiv.) instead of Cu(OAc)2	44
9	AgOPiv (1 equiv.) instead of Cu(OAc)2	42
10	Without AgOTf	n.r.
11	Without Cu(OAc)2	n.r.
12	1 equiv. of Cu(OAc)2	80
13	Reaction under O2	82
14	Reaction under N2	20

^{a 1}H NMR of the crude reaction mixture was obtained with 1,3,5-trimethoxybenzene as an internal standard.

^bIsolated yield.