Ni-catalyzed reductive amination of veratraldehyde: activity and selectivity of Ni-complexes^a.

Entry	Ligand	Conv. (%)	Yield (%)
			2	3	4	5
1a	L1	>99	96	—	3	—
2a	L2	15	—	—	13	—
3a	L3	23	—	—	21	—
4a	L4	20	—	—	18	—
5a	L5	12	—	—	10	—
6a	L6	5	—	—	3	—
7a	L7	5	—	—	3	—
8b	L1	>99	92	—	6	—
9c	L1	>99	91	—	7	—
10d	L1	>99	93	—	5	—
11a	—	10	—	—	8	—

^aReaction conditions: 0.5 mmol veratraldehyde, 4 mol% Ni(BF₄)₂·6H₂O, 4 mol% ligand, 5 bar NH₃, 40 bar H₂ 2 mL trifluoroethanol (TFE), 100 °C, 15 h, and GC yields using n-hexadecane as the standard.

^bSame as ‘a’ with 20 bar H₂.

^cSame as ‘a’ at 80 °C.

^dSame as ‘a’ with 3 mol% catalyst.