Table 5.

Chemoselectivity obtained by selection of catalyst and solvent.^a

Entry	Substrate	Catalyst	Solvent	Yield 19 (%)b	Yield 20 (%)b
1	18a	CuI	DMSO	0	61
2	18a	FeCl2·4H2O	DMSO	57	0
3	18a	CuI	n-BuOAc	78c	0
4	18bd	CuI	DMSO	0	62
5	18bd	FeCl2·4H2O	DMSO	85	0
6	18b	CuI	n-BuOAc	64	0

^aReactions were performed on a 0.5 mmol scale in 1 mL of solvent using 1 atmosphere of O₂ (balloon). ^bIsolated yields. ^c48 h. ^dReported in our communication, see [25].