Table 1:

Development of iron-catalyzed decarboxylative protonation^[a]

entry	Fe (a mol%)	ligand (b mol%)	disulfide (c mol%)	Na2CO3 (d mol%)	yield of 2 (%)
1	2.5	2.5	5	10	95
2	1	1	5	10	88
3	0.5	0.5	5	10	59
4	-	2.5	5	10	4
5	2.5	2.5	-	10	6
6[b]	2.5	2.5	5	10	25
7	2.5	2.5	5	-	38
8[c]	2.5	2.5	5	10	53
9[d]	2.5	2.5	5	10	N.R.
10[e]	2.5	2.5	5	10	77
11	2.5	-	5	10	72
12	2.5	-	15	10	81

^[a]All reactions were conducted on a 0.4 mmol scale and the yields were determined by ¹H NMR spectroscopy using trimethoxybenzene as an internal standard. TRIP disulfide = Bis(2,4,6-triisopropylphenyl) disulfide.

^[b]Diphenyl disulfide was used instead of TRIP disulfide.

^[c]427 nm LED light was used instead of 390 nm light.

^[d]No light; N.R. = no reaction.

^[e]DCE (0.1 M) was used as the solvent; Trace amount of α,β-unsaturated ketone was observed.