Table 2.

Optimization of Reaction Conditions for the Preparation of Potassium 4-Azidophenyltrifluoroborate (1b)^a

entry	CuX	ligand	base	reaction time (h)	conversion yield (%)b
1	CuI	a	K2CO3	24	66
2	CuI	b	K2CO3	5	98
3	CuI	c	K2CO3	16	100
4	CuI	d	K2CO3	24	81
5	CuI	e	K2CO3	15	100
6	CuI	f	K2CO3	1	100 (88)c
7	CuI	g	K2CO3	24	trace
8	CuI	h	K2CO3	48	68
9	CuId	f	K2CO3	2	100 (89)c
10	CuBr	f	K2CO3	1	100 (92)c
11	CuBr	f	Cs2CO3	0.5	100 (94)c
12e	CuBr	f	Cs2CO3	2.5	100

^aAll reactions were performed on a 0.05 mmol scale in 0.5 mL of DMSO-d₆ in an NMR tube.

^bPercent conversions were determined by ¹H NMR of the reaction mixtures. The conversion yield was based on the integration of peaks at 7.14 (1a-I) ppm and 6.85 (1b) ppm, respectively.

^cReactions were performed on a 0.1 mmol scale and isolated yields are reported.

^d5 mol % of CuI was used.

^eReaction was performed in DMF-d₇.