Table 1.

Optimization of polysulfide reagents^a,b

Entry	CuSO4 (mol%)	Ligand (mol%)	PhI(OPiv)2 (equiv)	Temp (°C)	Time (h)	Yields (%)
1c	10	bpy (10)	2.5	25	11	31
2d	10	bpy (10)	2.5	25	11	ND
3	10	bpy/ phen (10)	2.5	25	11	50/53
4	10	L1 (10)	2.5	25	11	77
5	10	L2/L3/L4 (10)	2.5	25	11	70/63/68
6	10	L1 (10)	2.5	20	13	86
7	5	L1 (10)	2.5	20	13	86
8	2.5	L1 (10)	2.5	20	13	79
9	5	L1 (5)	2.5	20	13	76
10	5	L1 (10)	2.2	20	13	88
11	5	L1 (10)	1.9	20	13	65

^aConditions: 1d (0.2 mmol, 1 equiv), CuSO₄·5H₂O, Ligand, Li₂CO₃ and PhI(OPiv)₂ were added to MeOH (2 mL) at 20 °C for 13 h

^bIsolated yields

^cPhI(OAc)₂ was instead of PhI(OPiv)₂

^dPhI(OTFA)₂ was instead of PhI(OPiv)₂