Table 1.

Solvent optimization for the synthesis of 1.

Entry	Solvent	Temperature (°C)	Yield (%)
1	Toluene	100	5
2	Toluene/H2O 4:1	100	40
3	Dioxane	100	39
4	Dioxane/H2O 4:1	100	74
5	DMF	100	22
6	Diglyme	100	42
7	MeCN	65	42
8	iPrOH	65	42
9	EtOH	65	11
10	THF	65	27
11	Dioxane/H2O 9:1	100	53
12a	Dioxane/H2O 4:1	100	72
13a,b	Dioxane/H2O 4:1	100	72
14c	Dioxane/H2O 4:1	100	52
15b,c	Dioxane/H2O 4:1	100	77
16	Dioxane/H2O 1:1	100	71
17	Dioxane/H2O 1:4	100	10
18	Dioxane/H2O 1:9	100	14

Note: Reaction conditions: PyFluor (0.3 mmol), 2-thiopheneboronic acid pinacol ester (0.45 mmol), Pd(dppf)Cl₂ (0.03 mmol), Na₃PO₄ (0.9 mmol), biphenyl (internal standard, 0.06 mmol), and solvent 1 mL in a closed 1 dram vial. Yield calculated using biphenyl as internal standard (HPLC/UV).

^aReaction performed in a 0.5 dram vial.

^bN₂ was bubbled through the reaction mixture during 15 min before heating.

^cReaction performed in a 3 dram vial.