Table 1. Calculated pK_eq values and Cu-catalyzed oxidation reaction for structurally different substrates.

Entry	Substrate	Product	pKeq	Yield a (%)
1			11.5	92 d
2			20.4	0 d
3			11.0	89 d
4			21.7	0 d
5			15.9	0 d
6			13.0	27 (60) b
7			6.2	23 (83) c
8			18.8	0
9			13.9	34 (85) b
10			19.0	0
11			9.1	98
12			8.1	99

^aSubstrate (0.5 mmol), CuI (10 mol%) AcOH (1 eq.), DMSO (1 mL), O₂ (balloon), 100 °C, 24 h.

^bAt 120 °C.

^cIn n-BuOAc (1 mL) with addition of molecular sieves.

^dCompound reported in our communication, see ref. 11a.