Evaluation of reaction conditions.

Entry	Variation from the standard condition	Yielda (%)
1	Other solvent instead of 1,4-dioxane	59–68
2	With 20 mol% Cu(OAc)2·H2O without CuCl	74
3	With 20 mol% CuCl without Cu(OAc)2·H2O	(54b)
4	Without [RuCl2(p-cymene)]2	(90b)
5	Without TEMPO	8 + (33b)
6	With 20 mol% TEMPO	24c
7	Replace O2 with air	22 + (24b)
8	No	86

^aIsolated yield of 3a.

^bIsolated yield of 4.

^c36 h.