Table 1. Development of C(sp³)-H-Functionalized 5-Annulation^a.

entry	catalyst	solventb	time (h)	yield (%)c
1	triflic acid	toluene	15	48
2	CSA	toluene	15	57
3	I2	toluene	2	79
4d	I2	EtOH	1.5	58
5	I2	EDC	1.5	70
6	I2	DMF	1.5	75
7	I2	DME	1.5	78
8	I2	dioxane	1	98
9d	I2	dioxane	6	95
10e	I2	dioxane	24	22
11f	I2	dioxane	12	79
12g	I2	dioxane	1	94
13		dioxane	24	NDh

^aReaction conditions: 1a (0.5 mmol), 2a (0.5 mmol), catalyst (20 mol %).

^bVolume of solvent: 2 mL.

^cYield of pure 4a after silica gel column chromatography using ethyl acetate in petroleum ether as an eluent.

^dUnder reflux (∼80 °C for EtOH and ∼100 °C for dioxane).

^eUnder argon.

^fCatalyst (15 mol %).

^gCatalyst (25 mol %).

^hNot detected.