Table 1.

HBC of 1-[¹⁸F]fluoro-4-iodobenzene ([¹⁸F]4) and piperazine. Total RCY is related to coupling yields based on [¹⁸F]4.

Entry	Catalyst System	Base	Solvent	Radiochemical Conversion Yield/Reaction Time
1	Pd2(dba)3/DavePhos	NaO tBu	Toluene	70%/15 min
2	Pd2(dba)3/RuPhos	NaO tBu	Toluene	73%/15 min
3	[CinnamylPdCl]2/BrettPhos	NaO tBu	Toluene	25%/30 min
4	Pd(OAc)2/RuPhos	NaO tBu	Toluene	60%/5 min 74%/10 min
5	Pd2(dba)3/DavePhos	NaO tBu	1,4-dioxane	40%/30 min
6	Pd2(dba)3/DavePhos	NaO tBu	DMF	0%/60 min
7	Pd(OAc)2/RuPhos	NaO tBu	DMF	0%/60 min
8	[P(tBu)3PdBr]2	K3PO4	DMF	0%/60 min
9	[P(tBu)3PdBr]2	K2CO3	DMF	0%/60 min
10	Pd2(dba)3/RuPhos	K3PO4	DMF	50%/6 min 88%/15 min
11	Pd[P(tBu)3]2	K3PO4	DMF	31%/15 min
12	Pd2(dba)3/JohnPhos	K3PO4	DMF	67%/15 min
13	Pd2(dba)3/JohnPhos	Cs2CO3	DMF	51%/15 min
14	Pd2(dba)3/XPhos	K3PO4	DMF	28%/15 min
15	Pd2(dba)3/XPhos	Cs2CO3	DMF	11%/15 min
16	Pd2(dba)3/RuPhos	K3PO4	DMSO	60%/15 min
17	Pd2(dba)3/RuPhos	Cs2CO3	DMSO	~95%/15 min
18	Pd2(dba)3/JohnPhos	K3PO4	DMSO	82%/15 min
19	Pd2(dba)3/XPhos	K3PO4	DMSO	77%/15 min