Table 1.

Optimization of Reaction Conditions.^[a]

Entry	T, °C	Time, h	Solvent	Cooxidant	Ratio 2/1
1[b,c]	150	12	DMF	AgOPiv	<1/99
2[b,c]	150	12	o-Cl2C6H4	AgOPiv	1/2 (33%)[h]
3[b,c]	150	12	CF3CH2OH	AgOPiv	>99/1 (63%)[h]
4	60	12	CF3CH2OH	AgOPiv	>99/1 (65%)[h]
5[b]	25	12	CF3CH2OH	AgOPiv	1/4 (16%)[h]
6	60	12	CF3CH2OH	K2S2O8	<1/99
7[d]	60	2	CF3CH2OH	PhI(OAc)2	1/1 (11%)[h]
8	60	16	CF3CH2OH	Mn(OAc)2	5/1 (79%)[h]
9[e]	80	2	CF3CH2OH	Mn(OAc)2	1/2 (63%)[h]
10[e,f]	80	12	CF3CH2OH	Mn(OAc)2	<1/99
11[g]	80	18	CF3CH2OH	O2	1/1 (50%)[h]
12[d]	80	2	CF3CH2OH	Mn(OAc)2	10/1 (87%)[h]

^[a]Amide 0.1 mmol, solvent 0.7 mL. Conversions were determined by ¹H NMR analysis.

^[b]Co(OAc)₂ catalyst.

^[c]Cooxidant: 0.8 equiv.

^[d]Cooxidant: 1 equiv.

^[e]Cooxidant: 0.5 equiv.

^[f]Deoxygenated solvent.

^[g]Reaction vessel pressurized with O₂.

^[h]NMR yield of 2 using 1,1,2-trichloroethane as internal standard in parentheses.