Optimization of reaction conditions^ab.

Entrya	PC	PC (mol%)	Additive	Solvent	LED	Yieldb (%)
1	Xanthone	5.0	—	MeCN	365 nm	15
2	Thioxanthone	5.0	—	MeCN	365 nm	—
3	fac-Ir(ppy)3	5.0	—	MeCN	365 nm	—
4	PC 1	5.0	—	MeCN	365 nm	79
5	PC 2	5.0	—	MeCN	365 nm	88
6	PC 3	5.0	—	MeCN	365 nm	—
7	PC 4	5.0	—	MeCN	365 nm	—
8	PC 2	5.0	—	MeCN	385 nm	90
9	PC 2	5.0	—	MeCN	Blue LED (100 W)	88
10	PC 2	1.0	—	MeCN	385 nm	83
11	PC 2	2.0	—	MeCN	385 nm	91 (90) c
12	PC 2	3.0	—	MeCN	385 nm	81
13	PC 2	4.0	—	MeCN	385 nm	83
14	PC 2	2.0	—	THF	385 nm	<5
15	PC 2	2.0	—	DMF	385 nm	—
16	PC 2	2.0	—	DCM	385 nm	51
17d	PC 2	5.0	DIPEA	MeCN	385 nm	29
18d	PC 2	5.0	Hantzsch ester	MeCN	385 nm	—
19	—	—	—	MeCN	385 nm	—
20e	PC 2	2.0	—	MeCN	385 nm	—
21f	PC 2	2.0	—	MeCN	385 nm	82c

^aReaction conditions: 1a (0.1 mmol) and PC (x mol%) were added to degassed MeCN (2.0 mL) under an Ar atmosphere for 12.0 h, in a sealed tube using LED light irradiation.

^bNMR yield using 1,3,5-trimethoxybenzene as an internal standard.

^cYield of the isolated products.

^dAdditive (0.2 mmol) was used.

^eUnder dark conditions.

^fA scale-up reaction with 1.0 mmol of 1a.