Table 1. Optimization of the sp³ C–H carbonylation ^a .

Entry	Oxidant	Base	Solvent	Yield b (%)
1		K2HPO4	MeNO2	0
2		K2HPO4	1,4-Dioxane	8
3		K2HPO4	MeCN	Trace
4		K2HPO4	tBuOH	11
5		K2HPO4	tAmOH	10
6		K2HPO4	iPrOH	14
7	O2	K2HPO4	iPrOH	Trace
8	AgOAc	K2HPO4	iPrOH	Trace
9	(tBuO)2	K2HPO4	iPrOH	18
10	Na2S2O8	K2HPO4	iPrOH	19
11	K2S2O8	K2HPO4	iPrOH	24
12	K2S2O8	Na2HPO4	iPrOH	26
13	K2S2O8	NaOAc	iPrOH	31
14	K2S2O8	PhCO2Na	iPrOH	39
15	K2S2O8	PhCO2Na	iPrOH/1,4-dioxane (0.45 : 0.55)	54
16 c	K2S2O8	PhCO2Na	iPrOH/1,4-dioxane (0.45 : 0.55)	65
17 c , d	K2S2O8	PhCO2Na	iPrOH/1,4-dioxane (0.45 : 0.55)	71(68)
18 c , d , e	K2S2O8	PhCO2Na	iPrOH/1,4-dioxane (0.45 : 0.55)	0
19 c , d , f	K2S2O8	PhCO2Na	iPrOH/1,4-dioxane (0.45 : 0.55)	0

^aReaction conditions: 1a (0.3 mmol), Cu(OAc)₂ (1 eq.), oxidant (2 eq.), base (1 eq.), solvent (2 mL), 165 °C, 24 h.

^bYields are based on 1a, determined by ¹H NMR using dibromomethane as the internal standard. Isolated yield is in parenthesis.

^cAl₂O₃ (60 mg).

^dDMPU (2 eq.).

^eNo MeNO₂.

^fNo Cu(OAc)₂.