Table 1. Selectivities among hydrogenation products (S1_2H and S1_4H) for the hydrogenation of S1 (20 bar, 60 °C, 16 h) with catalyst 1 at 1.8 mol% Cu_total loading. All reactions lead to complete conversion (>99%) of S1.

Entry	Ligand	L/S1 ratio	Sel. S12H (Z/E) (%)	Sel. S14H (%)
1	—	—	<1	>99
2	IMes	1 : 50	97 (99 : 1)	3
3	IMes	1 : 100	95 (98 : 2)	5
4	IMes	1 : 500	12 (58 : 42)	88
5	PCy3	1 : 50	66 (89 : 11)	34