Table 1.

Oxidative amination optimization.^[a]

Entry	CuX2·ligand	Base	Solvent	T [°C]	Yield [%][b]
1	Cu(OTf)2·2,2’-bipyridine	K2CO3	CF3Ph	120	65
2	Cu(eh)2	K2CO3	CF3Ph	120	70
3[c]	Cu(eh)2	K2CO3	CF3Ph	120	50
4	Cu(OTf)2·7	k2co3	CF3Ph	120	90[d]
5	Cu(OTf)2·7	–	CH3Ph	120	90[d]
6[e]	Cu(OTf)2·7	–	CH3Ph	120	80
7[f]	Cu(OTf)2·7	–	CH3Ph	120	25
8	Cu(OTf)2·7	–	DCE	105	65
9	Cu(OTf)2·7	k2co3	DCE	105	65
10	Cu(OTf)2·7	8	DCE	105	85[d]
11[g]	–	–	CH3Ph	120	20
12[h]	–	–	CH3Ph	120	n.r.
13[i]	Cu(OTf)2·7	–	CH3Ph	120	60
14[j]	Cu(OTf)2·7	–	CH3Ph	120	70
15[k]	Cu(OTf)2·7	–	CH3Ph	120	67
16	Cu(0Tf)2·1,10-phenanthro- line	–	CH3Ph	120	85
17[l]	Cu(OTf)2·7	8	DCE	105	15
18[m]	Cu(OTf)2·7	–	CH3Ph	120	50
19[n]	Cu(OTf)2·7	–	CH3Ph	120	trace

^[a]Conditions: Cu(X)₂ (0.04 mmol) and ligand (0.05 mmol) in solvent (1 mL) were heated for 2 h at 60 °C under Ar. Sulfonamide 5a (0.20 mmol), MnO₂ (0.60 mmol), solvent (1 mL), base (0.20 mmol), and flame-dried 4 Å molecular sieves (40 mg) were added. The solution was heated for 24 h in a sealed tube, then filtered through SiO₂ and concentrated.

^[b]onversion [%] based on crude NMR analysis.

^[c]Used copper(II) 2-ethylhexanoate [Cu(eh)₂] (3 equiv) and no oxidant.

^[d]Isolated yield following flash chromatography on silica gel.

^[e]Run with 15 mol% Cu(OTf)₂ and 18mol% 7.

^[f]Run with 50mol% Cu(OTf)₂·7 in the absence of MnO₂.

^[g]Run in then absence of a copper salt.

^[h]Run in the absence of MnO₂ and CuX₂.

^[i]Run with 2b (1 equiv).

^[j]Run with 2b (2 equiv).

^[k]Run with 2b (1 equiv), Cu(OTf)₂ (30 mol%), and 7 (38 mol%). N.r. = no reaction.

^[l]O₂ (1 atm, balloon) was used instead of MnO₂.

^[m]Run with MnO₂ (60 mol%) under O₂ (1 atm, balloon).

^[n]Run with 60 mol% MnO₂.