Table 2. Selective oxidation of aliphatic amides ^a .

^aUnless otherwise noted, the reaction conditions were as follows: 2a (0.1 mmol), TBAB (0.5 equiv.), Br₂ (1.2 equiv.), DCM 1.0 mL, rt, 15 min; then CuI (20 mol%), PhI(OTFA)₂ (2.2 equiv.), 100 °C, 5 h.

^b8 h.

^cPhI(OTFA)₂ (2.5 equiv.), 8 h.

^dAgOAc (20 mol%) instead of CuI (20 mol%), PhI(OTFA)₂ (2.5 equiv.), 8 h.

^ePhI(OTFA)₂ (3.0 equiv.), 8 h.

^fBRSM: based on recovered starting materials; isolated BRSM yield in parentheses.

^gND: not detected. Determined by crude ¹H NMR.

^hdr: determined by crude ¹H NMR.

ⁱCuI (20 mol%) instead of AgOAc (20 mol%).