Optimization of reaction condition^a.

Entry	Oxidant (equiv.)	PhI (equiv.)	Additive (3 equiv.)	Solvent	% yieldb
1	Oxone (3)	3	—	1,4-Dioxane	n.d.
2	NaIO4 (3)	3	—	1,4-Dioxane	n.d.
3	K2S2O8 (3)	3	—	1,4-Dioxane	n.d.
4	TBHP (3)	3	—	1,4-Dioxane	n.d.
5	NaBO3·H2O (3)	3	—	1,4-Dioxane	n.d.
6	mCPBA (3)	3	—	1,4-Dioxane	38
7	mCPBA (3)	3	—	Toluene	45
8	mCPBA (3)	3	AcOH	1,4-Dioxane	50
9	mCPBA (3)	3	AcOH	Toluene	70
10	mCPBA (3)	3	TsOH	Toluene	n.r.
11	mCPBA (3)	3	TFA	Toluene	60
12	mCPBA (3)	3	K2CO3	Toluene	n.r.
13	mCPBA (3)	3	PivOH	Toluene	90
14	mCPBA (3)	3	PivOH	CH3CN	16
15	mCPBA (3)	3	PivOH	MeOH	37
16	mCPBA (3)	3	PivOH	DCE	48
17	mCPBA (3)	3	PivOH	DMF	n.d.
18	mCPBA (3)	3	PivOH	DMSO	n.d.
19	mCPBA (1)	1	PivOH	Toluene	45
20	mCPBA (1.5)	1.5	PivOH	Toluene	68
21	mCPBA (2)	1.5	PivOH	Toluene	88
22	mCPBA (2)	1.5	AcOH	Toluene	70

^aReaction conditions: a mixture of oxidant and iodobenzene was heated at 50 °C for 5 h in a sealed tube. Then, 2a was added and the reaction mixture was refluxed.

^bGC yield.