Nature Communications

Table 1 Optimization of the reaction conditions^a.

From: Nickel-catalyzed deaminative Sonogashira coupling of alkylpyridinium salts enabled by NN₂ pincer ligand


Entry	Catalyst	Ligand	Base	Yield (%)^b
1	NiCl₂(glyme)	pybox	K₃PO₄	4
2	NiCl₂(glyme)	ttbtpy	K₃PO₄	53
3	NiCl₂(glyme)	L1	K₃PO₄	87
4	NiCl₂(glyme)	L2	K₃PO₄	83
5	NiCl₂(glyme)	L3	K₃PO₄	40
6	NiCl₂(glyme)	L4	K₃PO₄	96
7	Ni(acac)₂	L4	K₃PO₄	7
8	NiCl₂·6H₂O	L4	K₃PO₄	99 (97)^c
9	NiCl₂·6H₂O	L4	K₂CO₃	95
10	NiCl₂·6H₂O	L4	Et₃N	0
11^d	NiCl₂·6H₂O	L4	K₃PO₄	91
12^e	NiCl₂·6H₂O	L4	K₃PO₄	68
13	–	L4	K₃PO₄	0
14	NiCl₂·6H₂O	–	K₃PO₄	0
15	NiCl₂·6H₂O	L4	–	0

pybox pyridine bisoxazoline, ttbtpy 4,4′,4″-tri-tert-butyl terpyridine.
^aConditions: 1a (0.3 mmol), 2a (0.45 mmol), catalyst (10 mol%), ligand (10 mol%), base (1.3 equiv), THF (1.5 mL), 80 °C.
^bDetermined by ¹H NMR using 1,3,5-trimethoxybenzene as an internal standard.
^cIsolated yield.
^d5 mol% NiCl₂·6H₂O and L4 were used.
^eReaction was conducted at 60 °C.

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