Table 1.

Optimization studies for Paternò–Büchi cycloaddition.^a

entry	photocatalystb	solvent	yield
1	[Ir(dF(CF3)ppy)2(dtbbpy)]BArF (61)	MeCN	74%
2	[Ir(Fppy)2(dtbbpy)]PF6 (53)	MeCN	40%
3	[Ir(ppy)2(dMeObpy)]PF6 (51)	MeCN	5%
4	[Ir(ppy)2(dtbbpy)]PF6 (51)	MeCN	6%
5	[Ir(dF(CF3)ppy)2(dtbbpy)]BArF	CH2Cl2	81%
6	[Ir(dF(CF3)ppy)2(dtbbpy)]BArF	toluene	92%
7c	[Ir(dF(CF3)ppy)2(dtbbpy)]BArF	toluene	97%
8d	[Ir(dF(CF3)ppy)2(dtbbpy)]BArF	toluene	0%
9	none	toluene	15%

^aReactions conducted using 0.1 mmol 1, 0.5 mmol 2, 1 mol% photocatalyst, and 5 mL solvent and irradiated with a 16 W LED lamp (465 nm) for 16 h unless otherwise noted. Yields were determined by ¹H NMR analysis.

^bValues in parentheses represent the photocatalyst triplet energies in kcal/mol.

^cReaction conducted in 1.5 mL toluene.

^dReaction conducted in the dark.