Fig. 3: Scope of alkyl amines.

a Scope of primary alkylpyridinium salts. b Scope of benzylpyridinium salts. c Scope of secondary alkylpyridinium salts. d Scope of amino acid and peptide-derived pyridinium salts. Reaction conditions: 1 (0.3 mmol), 2a (0.45 mmol), NiCl2·6H2O (10 mol%), L4 (10 mol%), K3PO4 (1.3 equiv), THF (1.5 mL), 80 °C. Isolated yields. For 4g, 4h, 4p, 4q, 4r, 4s, 4t, 4u, 4v, 4w, 4y, 4z, and 4aa, reactions were conducted in DMF (1.5 mL). For 4m, 4n, and 4o, reactions were conducted at 50 °C.