Table 1. Reaction optimization ^a .

Entry	Mol% Cu(OTf)2	Ligand (mol%)	Solvent	Temp (°C)	Yield (%)
1 b	20	3a (25)	DCE	105	78
2	20	3a (25)	DCE	105	84
3	5	3a (6)	DCE	105	71
4	10	3a (12)	DCE	105	71
5	—	—	DCE	105	51
6	20	3a (25)	PhCH3	120	48
7	20	3a (25)	PhCF3	120	82
8	20	3a (25)	Dioxane	120	71
9	20	3b (25)	DCE	105	62
10	20	3c (25)	DCE	105	84
11	20	3d (25)	DCE	105	77
12	20	3e (25)	DCE	105	66
13	20	4a (25)	DCE	105	71
14	20	—	DCE	105	54
15 c	20	3a (25)	DCE	105	67
16 d	20	3a (25)	DCE	105	35
17 e	20	3a (25)	DCE	105	73

^aAll reactions were run in a sealed tube under argon with 0.125 mmol BnBF₃K and 1.5 equiv. of acid 1a in DCE (0.125 mM) unless otherwise noted.

^bReaction run with 1 equiv. of acid 1a.

^cReaction run with Ag₂CO₃ (1.3 equiv.) instead of MnO₂.

^dReaction run with K₂S₂O₈ (2.6 equiv.) instead of MnO₂.

^eReaction run with 1 mmol BnBF₃K.