Table 1.

Reaction development and optimization.

Entry	PC (1 mol%)	Solvent	Concentration [M]	1 (%)[a]	2 (%)[a]	3 (%)[a]
1	[Ir‐1]	MeCN	0.10	56	5	–
2	[Ir‐1]	MeCN	0.03	92 (90)[e]	2	–
3	[Ru‐1]	MeCN	0.03	4	–	–
4	[Ir‐2]	MeCN	0.03	18	–	–
5	[Ir‐3]	MeCN	0.03	88	–	–
6	[Cu‐1]	MeCN	0.03	80	4	–
7	[Ir‐1]	MeCN[b]	0.10	32	13	–
8 [c]	[Ir‐1]	MeCN	0.03	64	10	–
9	[Ir‐1][d]	MeCN	0.03	83	6	–
10	[Ir‐1]	DCM	0.03	–	30	53
11	[Ir‐1]	DMF	0.03	–	80	3
12	[Ir‐1]	DMF	0.17	–	86 (81)[e]	3
13	[Ir‐1]	DMA	0.03	–	6	–
14	[Ir‐1]	CHCl3	0.03	–	56	28
15	[Ir‐1]	Dry Et2O	0.03	–	9	75
16	[Ir‐1]	Toluene	0.03	–	16	76
17	[Ir‐1]	Toluene	0.17	–	14	81 (75)[e]
18	[Ir‐1]	THF : CHCl3 (1 : 1)	0.03	–	44	14

[a] General conditions: 4‐tert‐butylstyrene (0.5 mmol, 1 equiv), catalyst (1.0 mol %), and CDFAA (2 equiv), solvent (x M), 350 W blue LEDs, rt, 12 h. Yields of 1, 2, and 3 were determined by GC‐MS against an internal standard of n‐decane. [b] H₂O (1 equiv) was added. [c] Reaction was performed with 2‐bromo‐2,2‐difluoroacetic anhydride. [d] 2.5 mol % of fac‐Ir(ppy)₃. [e] Yields in parentheses represent isolated yields. [f] E _1/2 values were taken from refs. [5, 61, 62].