Table 1. Screening of the Effect of Catalysts and Solvents^a.

entry	catalyst	solvent	time (h)	yield (%)
1	I2	toluene	5	85
2		toluene	12	nr
3b	I2	toluene	7	83
4c	I2	toluene	7	70
5d	I2	toluene	7	85
6e	I2	toluene	7	65
7f	I2	toluene	7	85
8	KI	toluene	12	nr
9	I2	DCM	7	67
10	I2	MeCN	7	72
11	I2	1,4-dioxane	7	78
12	I2	DMSO	10	nr
13	I2	DMF	10	nr
14	I2	H2O	7	nr
15	I2	MeOH	7	nr
16	I2	EtOH	7	nr

^aReaction conditions: 1a (1.2 equiv), 2a (1 equiv), catalyst (5 mol %), solvent (2 mL), temp (40 °C), time (5 h), in air.

^bTemp (60 °C).

^cCatalyst (2 mol %).

^dCatalyst (10 mol %).

^eRoom temperature.

^fN₂ atmosphere.