In an argon-filled glovebox, a flame-dried 4 mL sealing tube equipped with a Teflon septum and magnetic stir bar was charged with Cp2ZrHCl (139.3 mg, 0.5 mmol, 2.7 equiv), the reaction vial was sealed tightly and removed from the glovebox, anhydrous THF (1.0 mL), alkenyl boronates (0.5 mmol, 2.5 equiv.) were added by a syringe under an argon atmosphere. The mixture was stirred at 50 o C for 1 h until a clear yellow solution was obtained. Another flame-dried 4 mL vial equipped with a Teflon septum and magnetic stir bar was charged with Ni(BF4)•6H2O (6.8 mg, 0.02 mmol, 20 mol%), L6 (10.0 mg, 0.024 mmol, 24 mol%). The vial was sealed, and then evacuated and back-filled with argon (3 times). Then anhydrous THF (1.0 mL) was added under argon. Then the mixture was stirred for 1h at room temperature. Another flame-dried 4 mL sealing tube equipped with a Teflon septum and magnetic stir bar was charged with NHPI ester (0.2 mmol, 1.0 equiv.), the tube was sealed, and then evacuated and back-filled with argon (3 times). The previous clear alkyl zirconium boronates reagent and the nickel catalyst were successively transferred via syringe over 1 min to this reaction vial under an argon atmosphere. The reaction mixture was then stirred and irradiated with 0.5 W blue LEDs in the photoreactor at 4 o C. After 24 h, the reaction mixture was concentrated in vacuum. Purification of the crude product by flash chromatography on silica gel afforded the desired product.