Optimization of the second step: solid-state ligand exchange of 3a with 2-phenylpyridine (2a) in the presence of silver salt^a.

Entry	Silver salt (2.0 equiv.)	Time (min)	Internal temp.b (°C)	Yield (%) of 4ac
1	AgOTf	60	135	73
2	None	60	135	12
3	AgOTf	60	30	5
4	AgOTf	30	135	70
5	Ag2O	60	135	10
6	Ag2CO3	60	135	14

^aConditions: 3a (0.05 mmol), silver salt (0.10 mmol), 2a (0.25 mmol), 2-methoxyethan-1-ol (0.20 μL mg⁻¹) in a stainless-steel milling jar (1.5 mL) with a stainless-steel ball (5 mm).

^bThe reaction temperature was controlled using a heat gun (for details, see the ESI). The internal temperature was confirmed by thermography immediately after opening the milling jar.

^cIsolated yields are shown.