Table 1. Optimization of reaction conditions ^a .

Entry	Ligand	Additive (mol%)	Yield b [%]
1	X-Phos	CuI (30%)	41
2	P(4-CF3C6H5)3	CuI (30%)	50
3	P(C6F5)3	CuI (30%)	39
4	C-Phos	CuI (30%)	32
5	P(4-CF3C6H4)3	CuI (10%)	5
6	P(4-CF3C6H4)3	CuI (50%)	56
7	P(4-CF3C6H4)3	CuI (100%)	72
8	P(4-CF3C6H4)3	CuI (200%)	80
9	P(4-CF3C6H4)3	CuI (250%)	80
10	P(4-CF3C6H4)3	CuBr·Me2S (200%)	83
11	P(4-CF3C6H4)3	CuTc (200%)	31
12	P(4-CF3C6H4)3	CuOAc (200%)	29
13 c	P(4-CF3C6H4)3	CuBr·Me2S (200%)	85
14 c , d	P(4-CF3C6H4)3	CuBr·Me2S (200%)	99
15 c , e	P(4-CF3C6H4)3	CuBr·Me2S (200%)	95 (92) f

^aReaction conditions (unless otherwise specified): 3a (0.1 mmol, 1.0 equiv.), PhB(OH)₂ (2.0 equiv.), Pd(PPh₃)₄ (10 mol%), ligand (20 mol%), additive (30 mol%), K₂CO₃ (2.0 equiv.), 1,4-dioxane (1 mL), 80 °C, and 20 h.

^bYields determined by ¹⁹F-NMR spectroscopy using trifluoromethylbenzene as an internal standard.

^cCs₂CO₃ instead of K₂CO₃.

^d5 Å molecular sieve (100 mg).

^ePd(PPh₃)₄ (1 mol%) and P(4-CF₃C₆H₄)₃ (2 mol%).

^fIsolated yield.