Table 1. Optimization of the Reaction Conditions^a.

entry	changes from the standard conditions	yield (%)b
1	none	78
2	KI (0.2 equiv) as the catalyst	trace
3	NaI (0.2 equiv) as the catalyst	trace
4c	I2 (0.2 equiv) as the catalyst	52
5	TBAI (0.2 equiv) as the catalyst	27
6	NIS (0.2 equiv) as the catalyst	47
7	I2 (0.1 equiv) as the catalyst	49
8	I2 (0.3 equiv) as the catalyst	53
9	DMF as the solvent	15
10	MeCN as the solvent	20
11	NMP as the solvent	43
12	toluene as the solvent	trace
13	temp = 100 °C	45
14	temp = 140 °C	50
15	TBHP (2 equiv)	52
16	TBHP (4 equiv)	60
17	no catalyst	trace
18	no oxidant	trace

^aReactions were performed on a 0.3 mmol scale, 1a (0.3 mmol) and 2a (0.54 mmol.).

^bIsolated yield.

^c2 equiv of TBHP was used.