Table 1. Effect of Deviation from Standard Reaction Conditions^a.

entry	variation from standard conditions	yieldb (%)
1	none	83 (82)c
2	no light	0
3	air atmosphere	28
4	no photocatalyst	0
5	0.5% [Ru] loading	52
6	(Ir[dF(CF3)ppy]2(dtbbpy))PF6 (1 mol %)	28
7	[Ir(dtbbpy)(ppy)2]PF6 (1 mol %)	16
8	no AscH2	0
9	AscH2 (2 equiv)	18
10	AscH2 (3 equiv)	79
11	Na-ascorbate instead of AscH2	0
12	30 min reaction time	36
13	MeOH	29
14	MeOH/H2O (10:1)	41
15	MeOH/H2O (6:1)	62
16	MeOH/H2O (2:1)	71
17	EtOH/H2O (1:1)	81
18	AcOH additive (10 vol %)	58
19	DMF	11
20	MeCN	0

^aFull reaction optimization in Tables S1–S7.

^bGC yield: average of two runs.

^cIsolated yield by SiO₂ column chromatography