Table 3. Treatment of CuI, NaBPh₄, and Different Ligands with CO₂ in MeOH^a.

entry	CuI [μmol]	ligand	t [h]	13C NMR (C2O42–)	CE (C2O42– (?)) [%]b
1	123	L2	120	n.d.	<0.5
2	124	L3	120	n.d.	<0.5
3	151	dpa	120	n.d.	2
4	184	dien	119	n.d.	28
5	409	dien	119	n.d.	10
6c	180	dien	120	n.d.	26
7	53	L4	114	n.d.	5
8d	63	L4	118	n.d.	29
9d	187	L4	119	n.d.	19
10d,e	187	L4	119	n.d.	28
11d,f	94	L4	118	n.d.	32
12c,d	63	L4	124	n.d.	3
13c,d	94	L4	118	n.d.	<0.5

^aReaction conditions: CuI/ligand/NaBPh₄ (1:1:1) was utilized in degassed MeOH under constant CO₂ atmosphere, unless stated otherwise. n.d. = not detected.

^bOxalate yields were calculated for signals coinciding with Na₂C₂O₄ added as internal standard after initial measurement and were found to overlap with the signal of iodide.

^cReaction conducted under Ar.

^dA total of 0.5 equiv of L4 was utilized.

^eReaction conducted with ¹³CO₂.

^fReaction conducted without NaBPh₄.